Mastering Biology Review #3

To survive, all animals must _____. See Concept 41.1
digest plant material
hibernate
balance consumption of food with use and storage of nutrients
ingest nutrients from the environment every day of their lives
have a complete digestive system

balance consumption of food with use and storage of nutrients

The "essential nutrients" for proper human nutrition include _____. See Concept 41.1 (Page 897)

calcium, sodium, potassium, and other minerals
active enzymes from plants and/or animals
glucose
all of the amino acids
cellulose

calcium, sodium, potassium, and other minerals

Birth defects of the neural tube in humans _____. See Concept 41.1 (Page 899)

are typically seen in 10-20% of male babies born in well-developed countries
are not affected by nutritional considerations during pregnancy
result from excess sodium in the pregnant woman's diet
can be prevented by ingestion of more vitamin A during the periconception interval
are reduced from about 6% without folic acid supplements in the periconception interval to about 1% when the supplements were taken

are reduced from about 6% without folic acid supplements in the periconception interval to about 1% when the supplements were taken

The following table shows the contents of a multivitamin supplement and its percentage of recommended daily values (%DV).

The most likely reason that some of the vitamins and minerals in this supplement are found at less than 100% is that _____.

The following table shows the contents of a multivitamin supplement and its percentage of recommended daily values (%DV).

Dietary Supplement % DV
Vitamin A 70
Vitamin C 100
Vitamin D 100
Vitamin E 150
Vitamin K 13
Vitamin B1 100
Vitamin B2 100
Folic acid 100
Vitamin B12 41.7
Calcium 20
Phosphorus 5
Iodine 100
Magnesium 25
Zinc 100
Copper 100
Chromium 125
Molybdenum 100
Iron 0

The most likely reason that some of the vitamins and minerals in this supplement are found at less than 100% is that _____.
it is too easy to overdose on minerals such as phosphorus and calcium
it is dangerous to overdose on fat-soluble vitamins such as A and K
it would be chemically impossible to add more
these vitamins and minerals are too large in size to reach 100%

it is dangerous to overdose on fat-soluble vitamins such as A and K

Animals that migrate great distances would obtain the greatest energetic benefit of storing chemical energy as _____.
fats
minerals
proteins
carbohydrates

fats

There is much discussion in the media about protecting biodiversity. But does biodiversity really matter? Canadian and Swiss researchers wanted to know if the diversity of arbuscular mycorrhizal fungi (AMF) was important to the productivity of grasslands (M.G.A. van der Heijden, J. N. Klironomos, M. Ursic, P. Moutoglis, R. Streitwolf-Engel, T. Boler, A. Wiemken, and I. R. Sanders. 1998. Mycorrhizal fungal diversity determines plant biodiversity, ecosystem variability, and productivity. Nature 396:69-72). Specifically, they wanted to know if it mattered which specific AMF species were present, or just that some type of AMF was present. They grew various plants in combination with one of four AMF species (A, B, C, and D), no AMF species (O), or all four AMF species together (A + B + C + D); and they measured plant growth under each set of conditions. All plant species were grown in each plot, so they always competed with each other, with the only difference being which AMF species were present.
On the graphs, the x-axis labels indicate the number and identity of AMF species (bar 0 = no fungi; bars A - D = individual AMF species; bar A + B + C + D = all AMF species together). The y-axis indicates the amount (grams) of plant biomass for the species shown in italics above each graph.

Examine all four graphs and choose the plant species that grows best with a combination of AMF species.
Centaurium erythrea (graph d)
Carex flacca (graph a)
Lotus corniculatus (graph b)
Sanguisorba officinalis (graph c)

Lotus corniculatus (graph b)

If a mammal did not obtain enough iodine in its diet, you might expect ________.

a decrease in enzyme function
the animal to have weak bones
a decrease in muscle function
a decreased ability to produce thyroid hormones

a decreased ability to produce thyroid hormones

Lysine is an essential amino acid for animals. If an animal did not consume lysine in its diet, you might expect that the animal ________.

could not effectively make many necessary proteins
was a carnivore
would make lysine from other amino acids
would be very healthy

could not effectively make many necessary proteins

Which of the following is a difference between vitamins and minerals?

Minerals are obtained by an animal through dietary sources, but vitamins are made by the animal.
Vitamins and minerals are only obtained by digesting plants.
Vitamins are organic molecules, but minerals are inorganic molecules.
Vitamins are involved in regulating enzyme activity, but minerals are not.

Vitamins are organic molecules, but minerals are inorganic molecules.

Folic acid supplements have become especially important for pregnant women because ________.

the fetus makes high levels of folic acid
folic acid supplies vitamins that only pregnant women can use
folic acid deprivation is associated with neural tube defects in a fetus
folic acid deprivation is a cause of heart abnormalities in a newborn

folic acid deprivation is associated with neural tube defects in a fetus

Three groups of cyclists consumed three different types of diets: high-carbohydrate; a diet mixed in carbohydrates, fat, and protein; or a diet higher in protein and fat. The average time each group could spend cycling over a six-hour period is shown in the accompanying graph. What conclusion from the data would help an athlete or trainer improve performance?

Maintaining elevated blood sugar improves performance.
Endurance is entirely related to diet.
An early 50 percent drop in blood glucose is associated with improved endurance.
Diet is not at all related to endurance.

Maintaining elevated blood sugar improves performance.

Choose the list that presents the four stages of food processing in the order in which they naturally occur. See Concept 41.2 (Page 900)

absorption → digestion → ingestion → elimination
ingestion → absorption → elimination → digestion
ingestion → digestion → elimination → absorption
ingestion → digestion → absorption → elimination
digestion → ingestion → absorption → elimination

ingestion → digestion → absorption → elimination

The gastrovascular cavity differs from the alimentary canal in that only the gastrovascular cavity _____. See Concept 41.2 (Page 902)

absorbs food molecules but does not produce hydrolytic enzymes
functions in digestion but not absorption
has only a single opening
stores food but does not digest it
is capable of extracellular digestion

has only a single opening

An advantage of a complete digestive system over a gastrovascular cavity is that the complete system _____.

excludes the need for extracellular digestion
allows extensive branching
allows for specialized regions with specialized functions
facilitates intracellular digestion

allows for specialized regions with specialized functions

Because the foods eaten by animals are often composed largely of macromolecules, animals need to have mechanisms for _____.

regurgitation
enzymatic hydrolysis
dehydration synthesis
demineralization

enzymatic hydrolysis

Fat digestion yields fatty acids and glycerol, whereas protein digestion yields amino acids; both digestive processes _____.

use water molecules when breaking bonds (hydrolysis)
are catalyzed by the same enzyme
require adenosine triphosphate (ATP) as an energy source
require the presence of hydrochloric acid to lower the pH

use water molecules when breaking bonds (hydrolysis)

Ticks are parasites that obtain nutrients by ingesting blood from a host animal. Ticks would be classified as ________.
filter feeders
substrate feeders
fluid feeders
bulk feeders

fluid feeders

The process of obtaining food is known as ________ and requires specialized feeding mechanisms.

excretion
absorption
ingestion
digestion

ingestion

In a hydra, digestion is completed ________.

extracellularly
in the gastrovascular cavity
intracellularly
in the alimentary canal

intracellularly

The process by which digested dietary substances cross cell membranes to be used by the body is known as ________.

absorption
digestion
ingestion
hydrolysis

absorption

Mechanical digestion, the process of breaking down large chunks of food into smaller pieces, is important because smaller pieces of food ________.

are more easily stored in the stomach than are larger pieces of food
are easier to excrete than are larger pieces of food
do not taste as good as larger pieces of food
have more surface area for chemical digestion than do larger pieces of food

have more surface area for chemical digestion than do larger pieces of food

When digested, proteins are broken down into _____.

glycerol only
fatty acids only
monosaccharides
amino acids
both glycerol and fatty acids

amino acids

When digested, fats are broken down into _____.

glycerol only
fatty acids only
monosaccharides
amino acids
both glycerol and fatty acids

both glycerol and fatty acids

Starch is a type of _____.
a. disaccharide
b. nucleotide
c. polysaccharide
d. fatty acid
e. monosaccharide

polysaccharide

Your small intestine can absorb ____ without their being further digested.

starches
fats
proteins
fructoses
nucleic acids

fructoses

Which of these enzymes begins the breakdown of starch?
bile
disaccharidases
lipase
amylase
nucleases

amylase

Starch can be broken down into the disaccharide known as _____.
lactose
glucose
sucrose
fructose
maltose

maltose

Protein digestion begins in the _____.
mouth
esophagus
stomach
small intestine
large intestine

stomach

What is the main component of gastric juice?
inactive pepsin
amylase
hydrochloric acid
water
bile

water

_____ is secreted by the _____ and acts to emulsify _____ in the _____.
Lipase ... small intestine ... fats ... small intestine
Trypsin ... pancreas ... fats ... small intestine
Nucleases ... pancreas ... nucleic acids ... stomach
Amylase ... salivary glands ... starch ... stomach
Bile ... liver ... fats ... small intestine

Bile ... liver ... fats ... small intestine

What acid is responsible for stomach acidity?
hydrochloric acid
carbonic acid
sulfuric acid
acetic acid
sodium hydroxide

hydrochloric acid

Which structure is not part of the alimentary canal?
Mouth.
Esophagus.
Salivary glands.
Stomach.

Salivary glands.

Which process is not required for an animal to obtain energy from food?

Ingestion.
Secretion.
Digestion.
Excretion.

Excretion

True or false? One advantage of having a tube-like digestive tract is that digestion of all compounds can take place simultaneously down the tract.
True
False

False

True or False? The liver is a component of the alimentary canal.

False

Choose the correct statement from the list below.

Mechanical digestion of proteins is more important than chemical digestion.
Proteins that are consumed in the diet are absorbed as individual amino acids following digestion.
Protein digestion begins in the small intestine with the activation of trypsinogen to trypsin
The stomach has a high pH which allows for the activation of digestive enzymes.

Proteins that are consumed in the diet are absorbed as individual amino acids following digestion.

Choose the correct statement from the list below.

Bile salts from the gall bladder are essential to the digestion of carbohydrates.
Carbohydrate digestion begins in the mouth with salivary amylase.
Carbohydrate absorption occurs primarily in the large intestine.
Carbohydrates are fully digested after passage through the stomach .

Carbohydrate digestion begins in the mouth with salivary amylase.

Choose the correct statement from the list below.

Bile salts from the pancreas are essential to the digestion of fats
Fats are fully digested after passage through the mouth and stomach.
Fat digestion begins in the stomach with the activation of trypsinogen to trypsin.
Free fatty acid absorption occurs in the small intestine.

Free fatty acid absorption occurs in the small intestine.

1. A fat molecule is composed of two types of smaller molecules, including only one molecule of .

Glycerol

2. A fat molecule also includes one, two, or three fatty acid molecules.

fatty acid

3. A fat molecule with only one fatty acid is called a monoglyceride.

monoglyceride

4. A fat molecule with three fatty acids is called a triacylglycerol, or a triglyceride.

triglyceride

5. A fatty acid includes a carboxyl group (-COOH) at one end as well as a long hydrocarbon chain.

hydrocarbons

6. The hydrocarbon chains found in fats store a lot of energy. They also make fats hydrophobic, or insoluble in water.

hydrophobic

Calculate the surface area of the cylinder that forms the "sides" of the microvillus rod. Use 3.14 for

0.30 μm2

Now calculate the surface area of the hemispherical top of the microvillus rod. Use 3.14 for

0.02 μm2

Now use your answers from Parts A and B to calculate the entire surface area of one microvillus (in

0.32 μm2

Suppose there are 2.0 x 109 microvilli per cm2 of intestinal epithelium. Calculate the total surface area of the microvilli in one cm2 of intestinal epithelium.

6.4 cm2

What is the percent increase in absorptive surface of the intestine due to the microvilli?

540%

Which of the following is an example of positive feedback in the lumen of the stomach?

Pepsin digests molecules of pepsinogen, producing more pepsin.
Pepsin works best in the acidic environment produced by hydrochloric acid.
Chief cells secrete pepsinogen, which is a precursor to pepsin.
Hydrochloric acid converts pepsinogen to pepsin.

Pepsin digests molecules of pepsinogen, producing more pepsin.

How do hydrogen ions (H+) and chloride ions (Cl-) get into the lumen of the stomach?

H+ is actively transported from parietal cells into the lumen, while Cl- diffuses from parietal cells into the lumen.
Parietal cells actively transport hydrochloric acid (HCl) into the lumen, and HCl then dissociates into H+ and Cl-.
Both H+ and Cl- diffuse from parietal cells into the lumen.
Parietal cells actively transport both H+ and Cl- into the lumen.

H+ is actively transported from parietal cells into the lumen, while Cl- diffuses from parietal cells into the lumen.

A researcher added a mixture of animal proteins to a physiological buffer solution (pH 7.4) in a test tube incubated at 37°C. The researcher then added purified pepsin to the mixture, but even after several hours, the proteins were not digested. Which of the following would explain this result?

The temperature was too low.
Pepsin doesn't digest animal proteins.
The pH was too high.
Pepsin must be converted to its active form, pepsinogen, which digests proteins.

The pH was too high.

What is one function of mucus in the lumen of the stomach?

It protects the epithelium from being digested by gastric juice.
It prevents H+ secreted by parietal cells from entering the lumen.
It prevents pepsinogen from digesting proteins inside chief cells.
It neutralizes HCl in the lumen.

It protects the epithelium from being digested by gastric juice.

The epithelium that lines the stomach has many deep infoldings, or pits. In what way do these pits function as glands?

They secrete the hormone pepsinogen into the blood.
They secrete food into the main chamber of the stomach.
They secrete a mixture of gastric juice and partially digested food into the small intestine.
They secrete gastric juice into the main chamber of the stomach.

They secrete gastric juice into the main chamber of the stomach.

Choose the correct anatomical sequence that presents the order in which food in the digestive system passes through. See Concept 41.3 (Page 903)

pharynx → esophagus → stomach → small intestine → large intestine
pharynx → small intestine → large intestine → stomach
esophagus → stomach → pharynx → small intestine
pharynx → stomach → esophagus → small intestine
esophagus → pharynx → stomach → small intestine

pharynx → esophagus → stomach → small intestine → large intestine

For ingested foods, the first opportunity for enzymatic digestion occurs in the _____. See Concept 41.3 (Page 903)

large intestine
stomach
pancreas
mouth
small intestine

mouth

The lower esophageal sphincter surrounds the upper opening into the stomach. If this sphincter failed to properly constrict, there might be a problem with _____. See Concept 41.3 (Page 905)

the movement of swallowed food into the trachea rather than into the esophagus
too rapid emptying from the stomach into the small intestine
too rapid emptying of the small intestine into the large intestine
regurgitation of acidic stomach contents into the esophagus, commonly called "heartburn"
the control of defecation

regurgitation of acidic stomach contents into the esophagus, commonly called "heartburn"

The large surface area in the gut directly facilitates _____.

absorption
temperature regulation
secretion
filtration

absorption

In the digestive system, peristalsis is _____.

smooth muscle contractions that move food along the esophagus
the transport of nutrients to the liver through the hepatic portal vessel
voluntary control of the rectal sphincters regulating defecation
a process of fat emulsification in the small intestine

smooth muscle contractions that move food along the esophagus

Among mammals, it is generally true that _____.

the epiglottis prevents swallowed food from entering the trachea
after leaving the oral cavity, the bolus enters the larynx
all types of foods begin their enzymatic digestion in the mouth
the trachea leads to the esophagus and then to the stomach

the epiglottis prevents swallowed food from entering the trachea

Stomach cells are moderately well adapted to the acidity and protein-digesting activities in the stomach by having _____.

Stomach cells are moderately well adapted to the acidity and protein-digesting activities in the stomach by having _____.
a thick, mucous secretion and active mitosis of epithelial cells
a sufficient colony of H. pylori
a high level of secretion of enzymes by chief cells
a cell wall impermeable to acid

a thick, mucous secretion and active mitosis of epithelial cells

Upon activation by stomach acidity, the secretions of the parietal cells _____.

initiate the mechanical digestion of lipids in the stomach
initiate the chemical digestion of lipids in the stomach
delay digestion until the food arrives in the small intestine
initiate the chemical digestion of protein in the stomach

initiate the chemical digestion of protein in the stomach

Jahasz-Pocsine and co-workers found a correlation between gastric bypass surgery and neurological complications. Surgeons performed gastric bypass surgery on 150 patients at the University of Arkansas for Medical Sciences Neurology Clinic. Of the 150 patients, 26 experienced neurological complications related to the surgery. What is the most likely cause for the neurological complications?

sudden weight loss and caloric deficiency interfering with neurological function
nutrient (for example, vitamin and mineral) deficiencies
infections following surgical intervention
sloppy surgical technique of physicians performing the bypass surgery

nutrient (for example, vitamin and mineral) deficiencies

Over-the-counter medications for acid reflux or heartburn block the production of stomach acid. Which of the following cells are directly affected by this medication?

Over-the-counter medications for acid reflux or heartburn block the production of stomach acid. Which of the following cells are directly affected by this medication?
chief cells
parietal cells
goblet cells
smooth muscle cells

parietal cells

The bile salts _____.
emulsify fats in the duodenum
are enzymes
are manufactured by the pancreas
are normally an ingredient of gastric juice

emulsify fats in the duodenum

The absorption of fats differs from that of carbohydrates in that _____.

carbohydrates need to be emulsified before they can be digested, whereas fats do not
fats, but not carbohydrates, are digested by bacteria before absorption
fat absorption primarily occurs in the stomach, whereas carbohydrates are absorbed from the small intestine
most absorbed fat first enters the lymphatic system, whereas carbohydrates directly enter the blood

most absorbed fat first enters the lymphatic system, whereas carbohydrates directly enter the blood

Constipation can result from the consumption of a substance that _____.

speeds up movement of material in the large intestine
decreases water reabsorption in the small intestine
stimulates peristalsis
promotes water reabsorption in the large intestine

promotes water reabsorption in the large intestine

After surgical removal of an infected gallbladder, a person must be especially careful to restrict dietary intake of _____.

water
fat
sugar
protein

fat

If you place a small piece of a cracker on your tongue, what would you expect to happen?

Salivary amylase degrades the starch from the cracker into maltose.
The vitamins in the cracker are immediately absorbed.
The proteins in the cracker begin to be digested.
The flavor becomes less noticeable because the sugars are digested.

Salivary amylase degrades the starch from the cracker into maltose.

Examine the digestive system structures in the figure. The agents that help emulsify fats are produced in location ________.

9 (Liver)

Examine the digestive system structures in the figure. The highest rate of nutrient absorption occurs at location ________.

4

Examine the digestive system structures in the figure. Most of the digestion of fats occurs in structure(s) ________.

4 only (small intestine)

Which of the following organs is correctly paired with its function?

large intestine: bile production
small intestine: polysaccharide digestion
stomach: fat digestion
pancreas: starch digestion

small intestine: polysaccharide digestion

The function of chylomicrons is to ________.

transport lipids from the intestine to other organs
digest nucleic acids in the intestine
move proteins across plasma membranes of cells
break down carbohydrates in the mouth

transport lipids from the intestine to other organs

What is the importance of the mucus that are released by salivary glands?

They aid in degradation of triglycerides to fatty acids and monoglycerides.
They are hormonal molecules that stimulate the release of gastric juice by the stomach in anticipation of receipt of the contents of the mouth.
They are glycoproteins that make food slippery enough to slide easily through the esophagus.
They are beginning the process of starch digestion.

They are glycoproteins that make food slippery enough to slide easily through the esophagus.

Why do the cells of the digestive system secrete proteolytic enzymes, such as pepsin, in their inactive forms?

Inactive pepsin and trypsin are more easily transported across the cell membrane
These proteolytic enzymes, in active form, would digest the very tissues that synthesize them.
By secreting inactive enzymes, the catalytic activity of the enzymes is maintained for a longer time.
The stomach is too acidic to maintain these enzymes in their active form.

These proteolytic enzymes, in active form, would digest the very tissues that synthesize them.

The active ingredient orlistat acts to decrease the amount of fat that is absorbed by attaching to enzymes that digest fat. Which of the following are potential targets of orlistat?

salivary amylase
pepsidase
pancreatic lipase
secretin

pancreatic lipase

The digestion of ________ begins in the stomach.

fat
carbohydrates
nucleic acids
protein

protein

Nutrient-rich blood from the intestine is carried through the ________ to the liver.
lacteal vessels
lymphatic system
hepatic portal vein
hepatic portal artery

hepatic portal vein

Pepsinogen is converted to its active form in the stomach by ________.

HCl
parietal cells
chief cells
high pH conditions

HCl

Different types of food are eaten by various groups of animals, but it is usually true that _____. See Concept 41.4 (Page 909)

the teeth of herbivores tend to be sharper than the teeth of carnivores
animals typically produce enzymes that hydrolyze cellulose
the intestines of carnivores tend to be longer than the intestines of herbivores of similar overall body size
many carnivorous vertebrates house large populations of symbiotic bacteria and protists in special fermentation chambers in their stomachs
cellulose digestion in ruminant mammals occurs before the ingested foods reach the small intestine

cellulose digestion in ruminant mammals occurs before the ingested foods reach the small intestine

A relatively long cecum is characteristic of animals that are_____.

autotrophs
omnivores
herbivores
carnivores

herbivores

Cattle are able to survive on a diet consisting almost entirely of plant material because cattle _____.

are autotrophic
re-ingest their feces
manufacture all fifteen amino acids out of sugars in the liver
have cellulose-digesting, symbiotic microorganisms in chambers of their stomachs

have cellulose-digesting, symbiotic microorganisms in chambers of their stomachs

Coprophagy is important for the nutritional balance of _____.

rabbits and their relatives
insects and arthropods
ruminants such as cows
squirrels and some rodents

rabbits and their relatives

If you found a vertebrate skull in the woods and the teeth were sharp and scissor-like, what type of food would you expect this animal to eat?

flesh of another animal
nectar
blood
grass

flesh of another animal

Examine the digestive system structures in the figure. Bacteria that produce vitamins are found in the greatest concentration in location ________.

5 (large intestine)

Animals cannot produce enzymes to digest cellulose, yet many termite species consume cellulose from plant material as a main part of their diet. How do termites access the nutrients contained in cellulose?

Cellulose is digested intracellularly in the termite hindgut.
Mutualistic bacteria in the hindgut of the termite digest the cellulose into sugars.
The ingested plant material also contains enzymes for cellulose digestion.
Termites have specialized mouthparts to mechanically break down the cellulose.

Mutualistic bacteria in the hindgut of the termite digest the cellulose into sugars.

A zoologist analyzes the jawbones of an extinct mammal and concludes that it was an herbivore. The zoologist most likely came to this conclusion based upon the ________.

size of the mouth opening
position of muscle attachment sites
angle of the teeth in the mouth
shape of the teeth

shape of the teeth

What benefit is gained by intestinal bacteria living in a mutualistic relationship with an animal?

The bacteria can avoid the animal's immune system.
Temperature is always regulated.
The bacteria can easily infect the animal's intestinal cells.
The bacteria are provided with a regular source of nutrients.

The bacteria are provided with a regular source of nutrients.

When used appropriately, antibiotic treatment can effectively reduce bacteria populations and help fight infections. However, antibiotic treatments can have unintended effects. What is one concern when using antibiotics?

Antibiotics may also kill the beneficial bacteria of the microbiome, thereby disrupting digestive health.
Each antibiotic is only effective against one type of bacteria, so effects on infection are limited.
Antibiotics cause viruses to become more effective at infecting cells.
Antibiotics also damage animal cells, so they can be more harmful than a bacterial infection.

Antibiotics may also kill the beneficial bacteria of the microbiome, thereby disrupting digestive health.

A significant contribution of intestinal bacteria to human nutrition is the benefit of bacterial ________.

recovery of water from fecal matter
production of vitamins A and C
production of vitamin K
absorption of organic materials

production of vitamin K

Locate the pie chart showing the microbiome of a healthy adult's intestinal tract. Which statement best represents the bacterial community composition of a healthy adult's intestinal tract?

Firmicutes are the most abundant bacteria in the intestinal tract of healthy adults, followed by roughly equal amounts of Bacteroidetes and Proteobacteria. Actinobacteria are also present in small amounts.
Firmicutes are the most abundant bacteria in the intestinal tract of healthy adults, followed by roughly equal amounts of Bacteroidetes and Actinobacteria. Proteobacteria are also present in small amounts.
Bacteroidetes are the most abundant bacteria in the intestinal tract of healthy adults, followed by Firmicutes and Other bacterial phyla. Proteobacteria are also present in small amounts.
Firmicutes are the most abundant bacteria in the intestinal tract of healthy adults, followed by Bacteroidetes and a small amount of Actinobacteria and Proteobacteria

Firmicutes are the most abundant bacteria in the intestinal tract of healthy adults, followed by Bacteroidetes and a small amount of Actinobacteria and Proteobacteria.

The graph here shows a comparison of the stomach microbiomes of healthy adults versus adults infected with Helicobacter pylori, a type of bacteria that has been linked to the formation of stomach ulcers.

Which statement best represents the bacterial community composition of a healthy adult's stomach?

Proteobacteria and Actinobacteria are the most abundant bacteria in the stomach of healthy adults.
Proteobacteria are the most abundant bacteria in the stomach of healthy adults, followed by miniscule amounts of Firmicutes, Actinobacteria, and Bacteroidetes.
Actinobacteria are the most abundant bacteria in the stomach of healthy adults, followed by roughly equal amounts of Bacteroidetes and Proteobacteria.
Actinobacteria are the most abundant bacteria in the stomach of healthy adults, followed by Firmicutes, and roughly equal amounts of Bacteroidetes and Proteobacteria.

Actinobacteria are the most abundant bacteria in the stomach of healthy adults, followed by Firmicutes, and roughly equal amounts of Bacteroidetes and Proteobacteria.

Compare the relative abundance of Actinobacteria in the microbiome of a healthy adult's intestinal tract to that of a healthy adult's stomach. Which statement best represents the relative abundance of Actinobacteria in each?

Actinobacteria are rare in both the stomach and intestinal tract of healthy adults.
Actinobacteria are rare in the stomach, but abundant in the intestinal tract of healthy adults.
Actinobacteria are abundant in both the stomach and intestinal tract of healthy adults.
Actinobacteria are abundant in the stomach, but rare in the intestinal tract of healthy adults.

Actinobacteria are abundant in the stomach, but rare in the intestinal tract of healthy adults.

Secretin stimulates the _____ to secrete _____.

pancreas ... bicarbonate

Cholecystokinin (CCK) stimulates the _____ to secrete _____.

pancreas ... pancreatic enzymes

The acidity of the stomach contents triggers the small intestine to secrete a hormone known as _____.

secretin

The presence of fatty acids and amino acids in the chyme from the stomach triggers the small intestine to secrete a hormone known as _____.

cholecystokinin, or CCK

Bile is produced by the _____ and stored by the _____ until it is secreted into the small intestine.

liver ... gall bladder

What are the roles of the ob and db genes in appetite regulation?
In this experiment, mice of specific genotypes were paired together.
Which of the following statements about the genotype pairings is correct?
Which of the following statements about the genotype pairings is correct?

Pairing (b) joined two mice that were mutants for the ob gene but wild-type for the db gene.

In what way did pairing (a) serve as a unique experimental control?

Only in pairing (a) were both mice wild-type for both genes.

Based on the data shown in the table, which of the following is a reasonable conclusion about the wild-type gene products?

The ob+ gene product circulated between both mice in a pair, even when only one mouse was wild-type for that gene.

What effect does the ob+ gene product appear to have on appetite?

The ob+ gene product suppresses appetite.

Which of these hypotheses could explain the result for pairing (d)?

The db+ gene product is the receptor for the ob+ satiety factor; the db mutant in pairing (d) cannot receive this receptor through the circulation and therefore overproduces the ob+ satiety factor.

If the results had been identical for pairings (a) and (b), what conclusion would you have drawn?

Differences in ob genotype do not affect the change in body mass of the mice.

At point A on the graph, how would the body respond?
Take insulin into the body's cells.
Take glycogen into the body's cells.
Secrete insulin.
Break down glycogen in liver cells

Secrete insulin.

How do glucagon and insulin differ?

Insulin is secreted when the blood glucose level is low, whereas glucagon is secreted when the blood glucose level is high.
Insulin is secreted from the pancreas, whereas glucagon is secreted from the liver.
Insulin causes some cells to take up glucose, whereas glucagon causes some cells to secrete glucose.
Insulin acts only on skeletal muscle cells, whereas glucagon acts only on liver cells.

Insulin causes some cells to take up glucose, whereas glucagon causes some cells to secrete glucose.

Which of the following hypothetical situations might result in a blood sugar level that is too high?

An individual's insulin receptors are defective. An individual has an autoimmune disorder that destroys the beta cells of the pancreas.

Among humans, increased interest in food intake normally occurs _____. See Concept 41.5 (Page 915)

via chemical signals released when the stomach is empty
via chemical signals related to the amount of glucose stored in the liver and muscle cells
only after the production of glucose in the liver can no longer meet metabolic needs
when fewer calories are taken in than are expended, but only after the body depletes its reserves of fat in the liver
via chemical signals related to the amount of protein stores in the liver

via chemical signals released when the stomach is empty

Obesity in humans is most clearly linked to _____.

type 2 diabetes and cardiovascular disease
type 1 diabetes and prostate cancer
type 2 diabetes and muscle hypertrophy
type 2 diabetes and decreased appetite

type 2 diabetes and cardiovascular disease

If you were to jog one kilometer a few hours after lunch, which stored fuel would you probably tap?

muscle proteins
fat stored in adipose tissue
liver glycogen and muscle glycogen
blood proteins

liver glycogen and muscle glycogen

When the digestion and absorption of organic carbohydrates results in more energy-rich molecules than are immediately required by an animal, the excess is _____.

stored as glycogen in the liver and muscles
eliminated in the feces
oxidized and converted to ATP
stored as starch in the liver

stored as glycogen in the liver and muscles

Food being digested in the stomach is in a highly acidic environment. When the food is released from the stomach into the small intestine, why is the environment no longer acidic?

Trypsinogen is activated, thus neutralizing the stomach acid.
Secretin increases the flow of bicarbonate ions from the pancreas into the small intestine to neutralize the stomach acid.
When pepsinogen activates pepsin, one result is the neutralization of stomach acid in the stomach.
Bile salts from the gallbladder neutralize the stomach acid.

Secretin increases the flow of bicarbonate ions from the pancreas into the small intestine to neutralize the stomach acid.

The Pimas are a group of people living in the southwestern United States and Mexico. Although Pima Indians living in the United States and Mexico have a similar genetic background, a five-fold increase in the incidence of type II diabetes mellitus among U.S. Pima has been reported. The body mass index of Mexicans of non-Pima descent, Mexicans of Pima descent, and Pimas living in the United States is shown in the figure. Based on this information and the graph, what can you infer about the incidence of type II diabetes mellitus?

The incidence of type II diabetes mellitus has increased in the past ten years.
People who develop type II diabetes mellitus are typically diagnosed in childhood or adolescence.
If you maintain a normal body weight (body mass index less than 25), you will not get type II diabetes mellitus.
Obesity is a risk factor for development of type II diabetes mellitus.

Obesity is a risk factor for development of type II diabetes mellitus.

In a healthy person, after a carbohydrate-rich meal, the production of ________ will increase, causing the uptake of ________ from the blood into liver cells.
In a healthy person, after a carbohydrate-rich meal, the production of ________ will increase, causing the uptake of ________ from the blood into liver cells.
insulin; glucagon
glucagon; glucose
insulin; glucose
glucagon; protein

insulin; glucose

If there is a strong genetic link for type II diabetes mellitus in your family, how might you minimize your risk of developing the disorder?

take oral insulin daily
eat complex carbohydrates like starch instead of sweets
maintain a healthy weight, eat a balanced diet, and exercise
monitor your blood glucose levels daily

maintain a healthy weight, eat a balanced diet, and exercise

A fasting animal whose energy needs exceed those provided in its diet will draw on its stored resources in which order?

fat, then glycogen, then protein
liver glycogen, then muscle glycogen, then fat
muscle glycogen, then fat, then liver glycogen
glycogen, then protein, then fat

liver glycogen, then muscle glycogen, then fat

Feelings of hunger can be stimulated by the hormone ________, but suppressed by the hormone ________.

secretin; gastrin
pepsin; trypsin
insulin; glucagon
ghrelin; PYY

ghrelin; PYY

The body tissue that consists largely of material located outside of cells is

epithelial tissue.
connective tissue.
smooth muscle.
skeletal muscle.
nervous tissue.

connective tissue.

Which of the following would increase the rate of heat exchange between an animal and its environment?

feathers or fur
blubber or fat layer
vasoconstriction
countercurrent heat exchanger
wind blowing across the body surface

wind blowing across the body surface

Consider the energy budgets for a human, an elephant, a penguin, a mouse, and a snake. The __________ would have the highest total annual energy expenditure, and the __________ would have the highest energy expenditure per unit mass.

elephant; mouse

Compared with a smaller cell, a larger cell of the same shape has

a smaller cytoplasm-to-nucleus ratio.
a smaller average distance between its mitochondria and the external source of oxygen.
less surface area per unit of volume.
the same surface-to-volume ratio.
less surface area.

less surface area per unit of volume.

An animal's inputs of energy and materials would exceed its outputs
if it is hibernating.
if it is growing and increasing its mass.
if the animal is an endotherm, which must always take in more energy because of its high metabolic rate.
if it is actively foraging for food.
never; homeostasis makes these energy and material budgets always balance.

if it is growing and increasing its mass.

You are studying a large tropical reptile that has a high and relatively stable body temperature. How would you determine whether this animal is an endotherm or an ectotherm?
You note that its environment has a high and stable temperature. Because its body temperature matches the environmental temperature, you conclude that it is an ectotherm.
You know that it is an ectotherm because it is not a bird or mammal.
You know from its high and stable body temperature that it must be an endotherm.
You subject this reptile to various temperatures in the lab and find that its body temperature and metabolic rate change with the ambient temperature. You conclude that it is an ectotherm.
You measure the metabolic rate of the reptile, and because it is higher than that of a related species that lives in temperate forests, you conclude that this reptile is an endotherm and its relative is an ectotherm.

You subject this reptile to various temperatures in the lab and find that its body temperature and metabolic rate change with the ambient temperature. You conclude that it is an ectotherm.

Which of the following animals uses the largest percentage of its energy budget for homeostatic regulation?
a desert insect
a snake in a temperate forest
a hydra
a desert bird
a marine jelly (an invertebrate)

a desert bird

Select the correct statement describing feedback control in animals.
Ectotherms are regulators with respect to temperature.
Positive feedback loops contribute to homeostasis.
An animal may be a regulator for one environmental variable but a conformer for another.

An animal may be a regulator for one environmental variable but a conformer for another.

How do endotherms and ectotherms differ?
ndotherms are regulators and ectotherms are conformers.
Endotherms are warm-blooded and ectotherms are cold-blooded.
Endotherms and ectotherms differ in the means by which they regulate their body temperature.

Endotherms and ectotherms differ in the means by which they regulate their body temperature.

Look at the graphs and choose the correct statement describing the relationship between BMR (basal metabolic rate) and body mass of mammals. (Look carefully at the quantity being displayed on the y-axis of each figure.)
BMR is roughly proportional to body mass squared.
Large mammals have lower basal metabolic rates than small mammals.
Small mammals have lower BMR, but use more calories per kilogram than large mammals.

Small mammals have lower BMR, but use more calories per kilogram than large mammals.

Tunas, sharks, penguins, and dolphins all have a basic fusiform shape, tapered at both ends. What explains this similarity in shape?
All fast-swimming aquatic vertebrates have this shape.
The similarity is due to homology, based on shared ancestry.
The similarity is due to convergent evolution, because all these animals share similar environmental challenges.

The similarity is due to convergent evolution, because all these animals share similar environmental challenges.

Which statement about endotherms and ectotherms is correct?
Endothermy is a more successful strategy for thermoregulation than ectothermy.
Ectotherms are more abundant and diverse than endotherms.
Ectotherms are more primitive than endotherms.

Ectotherms are more abundant and diverse than endotherms.

Which of these is NOT one of the four major categories of tissue?

blood

What type of epithelium would you expect to find covering a surface subject to physical forces?
simple epithelium
squamous epithelium
stratified epithelium
simple cuboidal cells
columnar epithelium

stratified epithelium

What type of epithelial tissue, found in the intestines, absorbs nutrients?

simple columnar epithelium

Which of these tissues, found in the lungs, permits gas exchange by diffusion?

simple squamous epithelium

What type of epithelial tissue lines kidney tubules?

simple cuboidal cells

How does connective tissue differ from the other three major tissue types?

Connective tissue often consists of relatively few cells embedded in an extracellular matrix.

Which of these describes loose connective tissue?

It is a loose weave of fibers that functions as a packing material.

Cartilage is found _____.
surrounding organs such as the kidneys
in the heart
at the ends of bones such as the femur
covering the surface of your body
connecting one bone to another

at the ends of bones such as the femur

_____ is the connective tissue specialized for transport.
Bone
Blood
Adipose tissue
Muscle tissue
Cartilage

Blood

A neuron consists of _____.
a cell body only
dendrites only
axons only
dendrites, a cell body, and axons
striations

dendrites, a cell body, and axons

Nervous tissue functions _____.
as a physical barrier to the invasion of pathogens
to physically move the body
to sense stimuli
to physically support the body
in the absorption of nutrients

to sense stimuli

What type of muscle is responsible for contractions of the digestive tract and arteries?
smooth muscle
skeletal muscle
striated muscle
voluntary muscle
cardiac muscle

smooth muscle

Cardiac muscle is the only muscle composed of _____ fibers.

branched

_____ muscle is attached to bones.

Skeletal

Penguins, seals, and tuna have body forms that permit rapid swimming, because _____.

the shape is a convergent evolutionary solution, which reduces drag while swimming

Much of the coordination of vertebrate body functions via chemical signals is accomplished by the _____.
integumentary system
respiratory system
endocrine system
excretory system

endocrine system

Compared with a smaller cell, a larger cell of the same shape has _____.
a smaller average distance between its mitochondria and the external source of oxygen
a smaller cytoplasm-to-nucleus ratio
less surface area per unit of volume
less surface area

less surface area per unit of volume

All animals, whether large or small, have _____.
most of their cells in contact with an aqueous medium
an external body surface that is dry
a basic body plan that resembles a two-layered sac
a body surface covered with hair to keep them warm

most of their cells in contact with an aqueous medium

Most of the exchange surfaces of multicellular animals are lined with _____.

epithelial tissue
connective tissue
neural tissue
smooth muscle cells

epithelial tissue

Connective tissues typically have _____.

little space between the membranes of adjacent cells
the ability to shorten upon stimulation
relatively few cells and a large amount of extracellular matrix
the ability to transmit electrochemical impulses

relatively few cells and a large amount of extracellular matrix

Blood is best classified as connective tissue because _____.

it contains more than one type of cell
it is found within all the organs of the body
its cells are separated from each other by an extracellular matrix
its cells can move from place to place

its cells are separated from each other by an extracellular matrix

Most types of communication between cells utilize _____.

the exchange of cytosol between the cells
the exchange of DNA between the cells
chemical or electrical signals
the movement of the cells

chemical or electrical signals

All types of muscle tissue have _____.

cells that lengthen when appropriately stimulated
a response that can be consciously controlled
interactions between actin and myosin
striated banding patterns seen under the microscope

interactions between actin and myosin

Cardiac muscle cells are both _____.

smooth and under involuntary control
smooth and under voluntary control
striated and interconnected by intercalated disks
striated and under voluntary control

striated and interconnected by intercalated disks

Food moves along the digestive tract as the result of contractions by _____.

striated muscle
cardiac muscle
smooth muscle
skeletal muscle

smooth muscle

Which of the following is a true statement about body size and physiology?

The rate at which an animal uses nutrients and produces waste products is independent of its volume.
Small and large animals face different physiological challenges because an animal's body mass increases cubically while its surface area increases as a squared function.
The amount of food and oxygen an animal requires and the amount of heat and waste it produces are inversely proportional to its mass.
The wastes produced by an animal double as its volume doubles and triple as its surface area triples.

Small and large animals face different physiological challenges because an animal's body mass increases cubically while its surface area increases as a squared function.

An elephant and a mouse are running in full sunlight, and both overheat by the same amount above their normal body temperatures. When they move into the shade and rest, which animal will cool down faster?

The elephant will because it has the higher surface-area-to-volume ratio.
The mouse will because it has the higher surface-area-to-volume ratio.
They will cool at the same rate because they overheated by the same amount.
The elephant will because it has the lower surface-area-to-volume ratio.

The mouse will because it has the higher surface-area-to-volume ratio.

You have a cube of modeling clay in your hands. Which of the following changes to the shape of this cube of clay will decrease its surface area relative to its volume?

Stretch the cube into a long, shoebox shape.
Flatten the cube into a pancake shape.
Round the clay up into a sphere.
Pinch the edges of the cube into small folds.

Round the clay up into a sphere.

Part A Part complete
Which of the following is a correct statement about an organism and its environment? See Concept 40.1 (Page 872)
View Available Hint(s)

The gastrovascular cavity provides the nutrient exchange surface in mammals.
An animal is a closed system that is separate and distinct from its environment.
Animals isolated from their environments live longer than those exchanging matter with the environment.
The interstitial fluid is the exchange medium between body cells and the circulatory system in vertebrate animals.
None of the choices is correct.

The interstitial fluid is the exchange medium between body cells and the circulatory system in vertebrate animals.

The four major categories of tissues are _____. See Concept 40.1 (Page 874)
View Available Hint(s)

blood, nervous, connective, and muscle
muscle, epithelial, bone, and cartilage
simple squamous, simple cuboidal, simple columnar, and stratified squamous
nervous, epithelial, connective, and muscle
bone, muscle, blood, and adipose

nervous, epithelial, connective, and muscle

As animals have evolved large body size, they have also evolved adaptations to improve exchange of energy and materials with the environment. For example, in many larger organisms, evolution has favored lungs and a digestive tract with ________.

increased thickness
decreased blood supply
larger cells
more branching or folds

more branching or folds

Both the endocrine and nervous systems transmit information around an animal's body. Which of the following is a characteristic of nervous system signals?

a voltage change must occur
allow gradual changes to take place in the body
travel quickly, allowing rapid transmission of signals
usually impact the entire body

travel quickly, allowing rapid transmission of signals

Some animals have no gills when young, but then develop gills that grow larger as the animal grows larger. What is the reason for this increase in gill size?

Relative to their surface area, the young have more body volume in which they can store oxygen for long periods of time.
The young of these animals are much more active than the adult, which leads to a higher BMR (basal metabolic rate) and, therefore, a higher need for oxygen.
Relative to their volume, the young have more surface area across which they can transport all the oxygen they need.
The young have a higher BMR.

Relative to their volume, the young have more surface area across which they can transport all the oxygen they need.

Evolutionary adaptations that help some animals directly exchange matter between the cells of their body and the environment include ________.

an unbranched internal surface, a small body size, and thick covering
a large body volume, a long, tubular body, and a set of wings
a gastrovascular cavity, a two-layered body, and a torpedo-like body shape
an external respiratory surface, a small body size, and a two-cell-layered body

an external respiratory surface, a small body size, and a two-cell-layered body

Interstitial fluid is ________.

identical to blood in composition.
found only in the lumen of the small intestine
the internal environment inside animal cells
a site of exchange between blood and body cells

a site of exchange between blood and body cells

Generally, epithelial cell layers are responsible for separating two fluids. For example, the epithelium of blood vessels in animals separates the blood from the interstitial fluid. What characteristic would you expect to see in an epithelium that was specialized for passive diffusion of materials from one fluid to another?

many layers of cells stacked together
a single layer of flattened cells
large, cube-shaped cells
loosely connected cells surrounded by an extracellular matrix

a single layer of flattened cells

In mammals, GH (growth hormone) is an endocrine signal that stimulates repair and growth of various tissues. Which of the following would be required for a tissue to respond to growth hormone?

a voltage change must occur
the presence of a growth hormone receptor on the responding tissue
nerve cells must attach to the responding tissue for growth hormone to work
the responding tissue must be muscle

the presence of a growth hormone receptor on the responding tissue

Muscle cells are organized to perform specific types of contractions within a tissue. Which of the following is a characteristic of smooth muscle?

spindle-shaped cells with a single nucleus
intercalated discs
striations with sarcomeres
many cells fused together

spindle-shaped cells with a single nucleus

In many animals, fat is stored in specialized cells in the ________.

muscle
adipose tissue
blood
bone

adipose tissue

Bone consists of ________.

many columnar epithelial cells packed together.
hardened fibrous connective tissue.
a mixture of hardened collagen and minerals.
chondroitin sulfate secreted by chondrocytes.

a mixture of hardened collagen and minerals.

What is the name of the epithelial cell surface that faces the outside of an organ?

lumen
interstitial
basal
apical

basal

Which organ system is responsible for protection against injury, infection, and dehydration?

Reproductive system
Excretory system
Integumentary system
Skeletal system

Integumentary system

The migratory eel, Anguilla rostrata, is born and lives the juvenile (immature) part of its life in a freshwater environment, but then migrates thousands of miles through the ocean as an adult in order to breed. These eels are known to regulate their internal water and salt balance. What adaptations would you expect this eel to have in order to transition from fresh water to salt water at these two life stages?

The juvenile eels would spend energy keeping water in their bodies.
The adult eels would spend energy keeping salt in their bodies.
The adult eels would be better at removing salt from their bodies compared to juveniles.
The juvenile eels would be better at removing salt from their bodies compared to adults.

The adult eels would be better at removing salt from their bodies compared to juveniles.

Which of these is an example of negative feedback?

As a blood clot begins to form, the process of its formation gets faster and faster.
After you eat, glucagon stimulates an increase in blood sugar levels.
After you eat, insulin stimulates the lowering of blood sugar levels.
The digestive enzyme pepsinogen is converted to pepsin by the action of hydrochloric acid; pepsin itself can then convert pepsinogen into pepsin.
Once labor begins, contractions increase in frequency and intensity.

After you eat, insulin stimulates the lowering of blood sugar levels.

Which term describes a steady state in which the internal conditions of an organism are kept within a narrow range without regard to the external conditions?
View Available Hint(s)

Regulatory homeostasis.
Negative feedback.
Thermoregulation.
Conformational homeostasis.

Regulatory homeostasis.

Which of the following actions is not a function of the epithelium?
View Available Hint(s)

Creates an internal environment that is different from the external environment.
Regulates the excretion of waste.
Controls the exchange of nutrients between the internal and external environments.
Allows the internal environment to alter its conditions to match those of the external environment.

Allows the internal environment to alter its conditions to match those of the external environment.

True or false? Organisms must maintain homeostasis because optimal enzyme activity is achieved within a very narrow range of conditions.
View Available Hint(s)

True
False

True

Which component of a homeostatic system compares sensory information to a target value?
View Available Hint(s)

Effector.
Integrator.
Set point.
Sensor.

Integrator.

Which component of a homeostatic system perceives changes in some parameter of the environment?
View Available Hint(s)

Set point.
Sensor.
Effector.
Integrator.

Sensor.

Which of the following actions acts to warm a homeothermic body?
View Available Hint(s)

Dilating blood vessels.
Panting.
Shivering.
Sweating.

Shivering.

Which of the following statements describes a negative feedback response?
View Available Hint(s)

The onset of contractions during childbirth stimulates the release of a hormone that stimulates further contractions.
After a meal, blood sugar levels in the body rise; insulin is secreted to lower blood sugar levels.
The arrival of platelets at a wound site stimulates the recruitment of more platelets to form a clot.
A person who loses 3 pounds continues to diet to lose an additional 10 pounds.

After a meal, blood sugar levels in the body rise; insulin is secreted to lower blood sugar levels.

When the body's blood glucose level rises, the pancreas secretes insulin and, as a result, the blood glucose level declines. When the blood glucose level is low, the pancreas secretes glucagon and, as a result, the blood glucose level rises. Such regulation of the blood glucose level is the result of _____.

positive feedback
protein-protein interactions
catalytic feedback
negative feedback

negative feedback

You discover a new species of bacteria that grows in aquatic environments with high salt levels. While studying these bacteria, you note that their internal environment is similar to the salt concentrations in their surroundings. You also discover that the internal salt concentrations of the bacteria change as the salt concentration in their environment changes. The new species can tolerate small changes in this way, but dies from large changes because it has no mechanism for altering its own internal salt levels. What type of homeostatic mechanism is this species using to regulate its internal salt levels?

regulation
integration
assimilation
conformation

conformation

Homeostasis is the _____. See Concept 40.2 (Page 879)
View Available Hint(s)

idea that all vertebrates are built in a similar way
correlation of structure and function
cooperation of body parts to form tissues, organs, and systems
exchange of materials with the surrounding environment
maintenance of a relatively constant and optimal internal environment

maintenance of a relatively constant and optimal internal environment

Negative feedback is a method of homeostatic control that _____. See Concept 40.2 (Page 879)
View Available Hint(s)

operates independently of most signaling mechanisms
ensures that conditions in an organism do not vary too much above or below their set points
produces a response by lowering the set point of an organism's metabolism
promotes decreases in metabolic rate rather than increases
increases the speed and rapidity of negative responses to environmental stimuli

ensures that conditions in an organism do not vary too much above or below their set points

In a physiological system operating with positive feedback, _____. See Concept 40.2 (Page 879)
View Available Hint(s)

a stimulus will initiate a response that returns the system to near its initial parameters
only an effector and control center are necessary to complete the control system
the range of acceptable values for a given parameter will be narrower than if the system were regulated by negative feedback
a change in a variable will amplify rather than reverse the change
a stimulus will prevent a small change from becoming too large

a change in a variable will amplify rather than reverse the change

The metamorphosis of a tadpole to an adult frog involves a thorough reconstruction of the animal's body. All of the structural and physiological changes must be complete or the frog will not survive this transformation. Which type of regulation would ensure that the animal completed its transformation?

enzymatic catalysis
positive feedback
feedback inhibition
negative feedback

positive feedback

The body's automatic tendency to maintain a constant and optimal internal environment is termed as ________.

static equilibrium
balanced equilibrium
homeostasis
physiological chance

homeostasis

An example of a properly functioning homeostatic control system is seen when ________.

the kidneys excrete salt into the urine when dietary salt levels rise
the core body temperature of a runner rises gradually from 37°C to 45°C
a blood cell shrinks when placed in a solution of salt and water
the blood pressure increases in response to an increase in blood volume

the kidneys excrete salt into the urine when dietary salt levels rise

a person were to travel to a time zone that was several hours ahead of their own, they may experience tiredness known as jet lag. Jet lag is due to a disruption of ________.

nerve impulses
homeostasis
circadian rhythm
body temperature

circadian rhythm

What would be an advantage for an animal that conforms to a changing environmental condition, such as temperature?

The animal's internal temperature would remain constant, even though the external temperature had changed.
The animal would spend less energy regulating its internal temperature.
The animal would spend more time looking for food.
The animal's internal temperature would change opposite to the change in the external temperature.

The animal would spend less energy regulating its internal temperature.

Chum salmon (Oncorhynchus keta) are born in freshwater environments and then migrate to the sea. Near the end of their lives, they return to the freshwater stream where they were born to spawn. In fresh water, water constantly diffuses into the body and ions are lost from the body. In salt water, body water diffuses out of the body and excess ions are gained from the water. A salmon's gills have special cells to pump salt in or out of the body to maintain homeostasis. In response to the salmon's moves between fresh water and salt water, some cells in the gills are produced and others are destroyed. These changes made in the cells of the gills during the lifetime of an individual salmon are an example of which of the following?

trade-off
evolution
acclimatization
adaptation

acclimatization

To prepare flight muscles for use on a cool morning, hawkmoths _____.

rapidly contract and relax these muscles to generate metabolic warmth
reduce the metabolic rate of the muscles to rest them before flight
relax the muscles completely until after they launch themselves into the air
decrease their standard metabolic rate

rapidly contract and relax these muscles to generate metabolic warmth

In a cool environment, an ectotherm is more likely to survive an extended period of food deprivation than would an equally sized endotherm because the ectotherm _____.

invests little energy in temperature regulation
expends more energy per kilogram of body mass than does the endotherm
has greater insulation on its body surface
maintains a higher basal metabolic rate

invests little energy in temperature regulation

An example of an ectothermic organism that has few or no behavioral options when it comes to its ability to adjust its body temperature is a _____.

honeybee in a hive on a rural farm
bass living in a farm pond
hummingbird flying through a prairie
sea star living deep in the ocean

sea star living deep in the ocean

The temperature-regulating center of vertebrate animals is located in the _____.

liver
thyroid gland
subcutaneous layer of the skin
hypothalamus

hypothalamus

Which of the following would increase the rate of heat exchange between an animal and its environment?

wind blowing across the body surface
feathers or fur
blubber or fat layer
vasoconstriction

wind blowing across the body surface

You are studying a large tropical reptile that has a high and relatively stable body temperature. How would you determine whether this animal is an endotherm or an ectotherm?

You note that its environment has a high and stable temperature. Because its body temperature matches the environmental temperature, you conclude that it is an ectotherm.
You know that it is an ectotherm because it is not a bird or mammal.
You know from its high and stable body temperature that it must be an endotherm.
You subject this reptile to various temperatures in the lab and find that its body temperature and metabolic rate change with the ambient temperature. You conclude that it is an ectotherm.

You subject this reptile to various temperatures in the lab and find that its body temperature and metabolic rate change with the ambient temperature. You conclude that it is an ectotherm.

A woman standing and watching the stars on a cool, calm night will lose most of her body heat by _____.

radiation
convection
conduction
evaporation

radiation

There are advantages and disadvantages to adaptations. Animals that are endothermic are likely to be at the greatest disadvantage in _____.

environments with a constant food source
very cold environments
environments with variable and limited food sources
very hot environments

environments with variable and limited food sources

Which principle of heat exchange is the most important explanation for why birds look larger in colder weather because they fluff their feathers?

Fluffing decreases the surface-area-to-volume ratio, thus decreasing the amount of heat lost to the environment.
Fluffing decreases the amount of heat lost by conduction when the bird makes contact with cold objects in its environment.
Fluffing creates a pocket of air near the bird that acts as insulation.
Fluffing feathers results in less cooling by radiation because feathers emit less infrared radiation than other tissues do.

Fluffing creates a pocket of air near the bird that acts as insulation.

What is the first thing that happens when body temperature increases above normal body temperature?

The thermostat in the hypothalamus activates cooling mechanisms.
Blood vessels in the skin constrict.
Sweat glands secrete sweat.
The thermostat in the blood vessels activates cooling mechanisms.

The thermostat in the hypothalamus activates cooling mechanisms.

Which of the following occurs when body temperature decreases below normal body temperature?

Skeletal muscles rapidly contract, cooling the body.
Sweat glands secrete sweat to cool the body.
Blood vessels in the skin constrict to help prevent heat loss.
Sweat glands secrete sweat to warm the body.

Blood vessels in the skin constrict to help prevent heat loss.

Which of the following primarily involves heat transfer by convection? See Concept 40.3 (Page 882)
View Available Hint(s)

The water in the lake is so cold that your legs become numb.
As you lie on the sand, you can feel the sun's warm rays on your skin.
You roll down the car window to allow the cool breeze to blow through.
After sunset, you can feel heat from the warm pavement.
You sweat profusely as you mow the lawn on a hot summer day.

You roll down the car window to allow the cool breeze to blow through.

A countercurrent heat exchanger enables an animal to _____. See Concept 40.3 (Page 883)
View Available Hint(s)

slow metabolism when food is not available
reduce the loss of body heat to the environment
produce more heat when needed
increase heat loss by evaporation
absorb heat from the environment

reduce the loss of body heat to the environment

Bats and hummingbirds are examples of _____. See Concept 40.3 (Page 882)
View Available Hint(s)

ectotherms that are also poikilotherms
endotherms that are also poikilotherms
endotherms that are also homeotherms
ectotherms that are also homeotherms
endotherms that are also ectotherms

endotherms that are also poikilotherms

Elephants can often be observed cooling off by spraying water over their bodies with their trunks. What type of heat exchange is occurring?

evaporation
conduction
convection
radiation

evaporation

The panting responses observed in overheated birds and mammals dissipate excess heat by ________.

countercurrent exchange
acclimation
evaporation
vasoconstriction

evaporation

Most land-dwelling invertebrates and all of the amphibians ________.

become more active when environmental temperatures drop below 15°C
alter their metabolic rates to maintain a constant body temperature of 37°C
are ectothermic organisms with variable body temperatures
are endotherms but become thermo-conformers when they are in water

are ectothermic organisms with variable body temperatures

Part A Part complete
The metabolic breakdown of specialized brown fat deposits in certain animals is substantially increased during ________.

torpor
shivering thermogenesis
acclimatization
nonshivering thermogenesis

nonshivering thermogenesis

The use of brown fat to generate metabolic heat is mostly limited to small mammals. What is the basis of this adaptation?

Large mammals have lost their brown fat through the course of their evolution.
Small mammals cannot grow enough fur to insulate their bodies.
Small mammals do not have enough muscle to generate heat by shivering.
Because of their large surface area to volume ratio, heat loss across the body surface is higher in small animals.

Because of their large surface area to volume ratio, heat loss across the body surface is higher in small animals.

The thin horizontal arrows in the figure above show that the ________.

arterial blood is always cooler in the abdomen, compared to the temperature of the venous blood in the feet of the goose
warmer arterial blood transfers heat to the cooler venous blood
warmer arterial blood can bypass the legs as needed, when the legs are too cold to function well
warmer venous blood transfers heat to the cooler arterial blood

warmer arterial blood transfers heat to the cooler venous blood

The countercurrent arrangement of blood vessels is an adaptation that allows the goose to ________.
Use the figure to answer the following question.

A diagram shows circulation in the leg of a Canada goose. Blood in an artery is at 35 degrees Celsius, moving downward to the bottom of the leg. The temperature decreases to 30, 20, then 10 degrees Celsius. The blood vessel then curves back upwards, such that the vein passes alongside the artery. Heat transfer is shown by thin horizontal arrows, transferring from the artery to the vein. The blood in the vein increases from 9 to 18 to 27 and finally 33 degrees Celsius in the diagram. The warmed blood returns to the body.

The countercurrent arrangement of blood vessels is an adaptation that allows the goose to ________.
minimize heat exchange between the feet and water
generate heat using shivering thermogenesis
conserve heat in its core when the goose is swimming in cold water
more effectively cool off in the summer

conserve heat in its core when the goose is swimming in cold water

Based on graph (a), one observer suggests that a group of 100 ground squirrels would consume the same amount of oxygen per hour as 1 dog because 100 ground squirrels have the same total body mass as 1 dog. A second observer disagrees.
Who is correct?

The first observer is correct; 100 ground squirrels consume about 10 liters of oxygen per hour, the same amount as 1 dog.
The second observer is correct; 100 ground squirrels will consume less oxygen per hour than 1 dog.
The first observer is correct; 1 dog consumes about 3 liters of oxygen per hour, the same amount as 100 ground squirrels.
The second observer is correct; 100 ground squirrels will consume more oxygen per hour than 1 dog.

The second observer is correct; 100 ground squirrels will consume more oxygen per hour than 1 dog.

You can estimate the contribution of each wedge in a pie chart by remembering that the entire circle represents 100%, half is 50%, and so on.
What percent of the mouse's energy budget goes to basal metabolism?

about 25%

What percent of the penguin's budget is for activity?
What percent of the penguin's budget is for activity?
about 10%
about 35%
almost 50%
almost 100%

almost 50%

Without considering the sizes of the wedges, how do the three pie charts differ in which functions they include?
Without considering the sizes of the wedges, how do the three pie charts differ in which functions they include?
The python chart is the only one that includes activity.
The penguin chart is the only one that includes thermoregulation.
Unlike the penguin and mouse charts, the python chart includes growth but does not include thermoregulation.
Unlike the mouse and python charts, the penguin chart does not include reproduction.

Unlike the penguin and mouse charts, the python chart includes growth but does not include thermoregulation.

Why does the pie chart for the python include growth but not thermoregulation?
Why does the pie chart for the python include growth but not thermoregulation?
The python grows throughout its life, and it is an ectotherm.
Only four variables can be shown in a pie chart, and growth is more important than thermoregulation in a python's energy budget.
Energy used for thermoregulation could not be measured for the python.
The python grows throughout its life, but it does not thermoregulate.

The python grows throughout its life, and it is an ectotherm.

Does the penguin or the mouse expend a greater proportion of its energy budget on thermoregulation? Why?
Does the penguin or the mouse expend a greater proportion of its energy budget on thermoregulation? Why?
The penguin expends a greater proportion of its energy budget on thermoregulation because of its extremely cold Antarctic habitat.
The mouse expends a greater proportion of its energy budget on thermoregulation because of its small size.
The penguin expends a greater proportion of its energy budget on thermoregulation because of its large size.
The mouse expends a greater proportion of its energy budget on thermoregulation because of its temperate habitat.

The mouse expends a greater proportion of its energy budget on thermoregulation because of its small size.

Now look at the total annual energy expenditures for each animal.
How much more energy does the penguin expend each year compared to the similarly sized python?
How much more energy does the penguin expend each year compared to the similarly sized python?
The penguin expends 2 times as much energy as the python.
The penguin expends 42.5 times as much energy as the python.
The penguin expends 85 times as much energy as the python.
The penguin expends 332,000 times as much energy as the python.

The penguin expends 42.5 times as much energy as the python.

Which animal expends the most kilocalories per year on thermoregulation?
Which animal expends the most kilocalories per year on thermoregulation?
the mouse
the python
the penguin

the penguin

Given that adult penguins don't grow from year to year, how would you explain this finding?
Given that adult penguins don't grow from year to year, how would you explain this finding?
At certain times, penguins store considerable energy as fat, putting on weight in the process.
For several months after hatching, penguin chicks use a large proportion of the energy available to them to grow.
During the breeding season, penguins produce new biomass when they lay eggs and feed their chicks.
At certain times, penguins use up their fat stores, losing considerable weight.

At certain times, penguins store considerable energy as fat, putting on weight in the process.

Snake behavior in Wisconsin changes throughout the year. For example, a snake is _____.
Snake behavior in Wisconsin changes throughout the year. For example, a snake is _____.
less active in winter because the food supply is decreased
more active in summer because it can gain body heat by conduction
less active in winter because it does not need to avoid predators
more active in summer because that is the period for mating

more active in summer because it can gain body heat by conduction

Standard metabolic rate (SMR) and basal metabolic rate (BMR) are _____.
both measured across a wide range of temperatures for a given species
used differently: SMR is measured during exercise, whereas BMR is measured at rest
both measured in animals in a resting and fasting state
used to compare metabolic rates during feeding and other active conditions

both measured in animals in a resting and fasting state

Consider the energy budgets for a human, an elephant, a penguin, a mouse, and a snake. The _____ would have the highest total annual energy expenditure, and the _____ would have the highest energy expenditure per unit mass.
mouse; snake
elephant; human
human; penguin
elephant; mouse

elephant; mouse

Which of the following animals most likely uses the largest percentage of its energy budget for homeostatic regulation?
a bird living year round in a desert
a snake in a tropical forest
a shark swimming in the open ocean
a marine jelly (an invertebrate) living deep in the ocean

a bird living year round in a desert

Hummingbirds are small birds that require a regular food supply. When hummingbirds are faced with a situation that decreases their food supply, such as a storm, which of the following adaptations would be most useful for the bird to survive such an unpredictable and short-term absence of food resources?
hibernation
shivering
torpor
burrowing into soil

torpor

Metabolic rate is _____. See Concept 40.4 (Page 888)
typically higher in an ectothermic animal than in an endothermic one
directly proportional to body size
the total amount of energy an animal uses in a unit of time
the amount of heat gained by an animal in a unit of time
determined when the organism is vigorously exercising after consuming a fatty meal

the total amount of energy an animal uses in a unit of time

Choose the list that correctly ranks metabolic rates per gram of body mass, from lowest to highest. See Concept 40.4 (Page 889)
gazelle, lion, elephant
human, cat, mouse, salamander
fish, dog, mouse
human, rabbit, snake
hummingbird, dog, mouse

fish, dog, mouse

The metabolic rate of an animal is most accurately determined by ________.
the amount of carbon dioxide produced by an animal in a given time.
the amount of energy used by an animal in a given time
the amount of work done by an animal
the amount of food consumed during a meal

the amount of energy used by an animal in a given time

Independent of whether an organism is an endotherm or ectoderm, the least reliable indicator of an animal's metabolic rate is the amount of ________.
water consumed in one day
food eaten in one day
heat generated in one day
oxygen used in mitochondria in one day

water consumed in one day

What can you determine from the graph?
A shrew uses more energy than an elephant.
A smaller animal would consume less food per gram of tissue.
An animal with a larger mass has a lower metabolic rate per gram of tissue relative to an animal with smaller mass.
An elephant uses more energy than a shrew.

An animal with a larger mass has a lower metabolic rate per gram of tissue relative to an animal with smaller mass.

A researcher is setting up an experiment to measure basal metabolic rate in prairie voles (Microtus ochrogastera small rodent). Which of the following would be the best set of conditions for the voles immediately before and during the measurement?
A researcher is setting up an experiment to measure basal metabolic rate in prairie voles (Microtus ochrogastera small rodent). Which of the following would be the best set of conditions for the voles immediately before and during the measurement?
House the animals in a cage with no food for a few hours before measurement; conduct measurements in a room the same temperature as the room where housed.
House the animals in a cage with plenty of food and water to avoid stress; conduct measurements in a room the same temperature as the room where housed.
House the animals in a cage with no food for a few hours before measurement; conduct measurements in a colder room than the room where housed, and exercise the voles.
House the animals in a cage with plenty of food and water to avoid stress; conduct measurements in a warmer room than the room where housed.

House the animals in a cage with no food for a few hours before measurement; conduct measurements in a room the same temperature as the room where housed.

Organisms maintain dynamic homeostasis through behavioral and physiological mechanisms. Which of the following statements is an accurate explanation of a negative feedback mechanism used by animals to regulate body temperature?
Squirrels are able to cool themselves during warmer months by producing more brown fat, which contains abundant mitochondria and a rich blood supply.
Desert jackrabbits have unusually large ears that serve as solar heat collectors to enable them to maintain their body temperatures.
A ground squirrel's hypothalamus detects changes in environmental temperatures and responds by activating or suppressing metabolic heat production.
A goldfish slows its movements when the water temperature is lower.

A ground squirrel's hypothalamus detects changes in environmental temperatures and responds by activating or suppressing metabolic heat production.

An emergent property belongs to
An emergent property belongs to
the parts of something but not the whole.
both the parts and the whole of something.
the newest part of something.
the whole of something but not its parts.

the whole of something but not its parts.

Imagine you have two sets of 8 blocks, each measuring 1 cm along each edge. You arrange one set into a large cube, 2 blocks × 2 blocks × 2 blocks. You arrange the other set into a straight beam, 1 block × 8 blocks. Compared with the beam, the large cube has
Imagine you have two sets of 8 blocks, each measuring 1 along each edge. You arrange one set into a large cube, 2 blocks 2 blocks 2 blocks. You arrange the other set into a straight beam, 1 block 8 blocks. Compared with the beam, the large cube has
the same volume and surface area.
the same volume but a smaller surface area.
a smaller volume and surface area.
a greater volume and surface area.

the same volume but a smaller surface area.

Natural selection refers to
the evolution of an individual organism.
the outcome of evolution.
a goal of evolution.
a mechanism of evolution.

a mechanism of evolution.

According to the hypothesis of serial endosymbiosis, which of the following was a key initial step in the origin of mitochondria?

A prokaryotic host cell engulfed an aerobic, photosynthetic bacterium.
A eukaryotic host cell engulfed an aerobic, photosynthetic bacterium.
A eukaryotic host cell engulfed an aerobic, heterotrophic bacterium.
A prokaryotic host cell engulfed an aerobic, heterotrophic bacterium.

A prokaryotic host cell engulfed an aerobic, heterotrophic bacterium.

Which of the following domains consists of all the organisms whose cells have true nuclei?

Bacteria
Animalia
Eukarya
Archaea

Eukarya

A diploid (2n) cell divides by meiosis, producing four daughter cells. Next, each daughter cell divides by mitosis, producing a total of eight granddaughter cells. Which of the following statements about the granddaughter cells is true?

Each granddaughter cell is haploid (n).

According to the endosymbiotic theory, why was it adaptive for the larger (host) cell to keep the engulfed cell alive, rather than digesting it as food?

The engulfed cell provided the host cell with carbon dioxide.
The engulfed cell allowed the host cell to metabolize glucose.
The engulfed cell provided the host cell with adenosine triphosphate (ATP).
The host cell was able to survive anaerobic conditions with the engulfed cell alive.

The engulfed cell provided the host cell with adenosine triphosphate (ATP).

The chloroplasts of land plants are thought to have been derived according to which evolutionary sequence?

cyanobacteria → red algae → green algae → land plants
cyanobacteria → green algae → fungi → land plants
cyanobacteria → green algae → land plants
red algae → brown algae → green algae → land plants

cyanobacteria → green algae → land plants

A particular species of protist has obtained a chloroplast via secondary endosymbiosis. You know this because the chloroplasts _____.

are exceptionally small
have only a single pigment
have nuclear and cyanobacterial genes
have three or four membranes

have three or four membranes

All protists are _____.

eukaryotic
symbionts
mixotrophic
unicellular

eukaryotic

An individual mixotroph loses its plastids, yet continues to survive. Which of the following most likely accounts for its continued survival?

It engulfs organic material by phagocytosis or by absorption.
It relies on photosystems that float freely in its cytosol.
It has an endospore.
It must have gained extra mitochondria when it lost its plastids.

It engulfs organic material by phagocytosis or by absorption.

Which process could have allowed the nucleomorphs of chlorarachniophytes to be reduced, without the net loss of any genetic information?

conjugation
horizontal gene transfer
meiosis
phagocytosis

horizontal gene transfer

Why has the kingdom Protista been abandoned? See Concept 28.1 (Page 592)
View Available Hint(s)

Some protists are multicellular.
The kingdom Protista is not monophyletic.
Some protists are more closely related to plants, animals, or fungi than they are to other protists.
Some protists are as small as prokaryotes.
The second and third answers are correct.

The second and third answers are correct.

Which of the following is true of secondary endosymbiosis? See Concept 28.1 (Page 593)
View Available Hint(s)

It is indicated by the presence of a double membrane surrounding the endymbiont.
An organism containing one endosymbiont engulfs another organism, and that organism becomes an endosymbiont.
It is indicated by the presence of a nucleomorph.
An organism containing an endosymbiont is engulfed by another organism and becomes an endosymbiont.
It is indicated by the presence of a mixotroph.

An organism containing an endosymbiont is engulfed by another organism and becomes an endosymbiont.

Use the following information to answer the question.

Paulinella chromatophora is one of the few cercozoans that is autotrophic, carrying out aerobic photosynthesis with its two elongated "chromatophores." The chromatophores are contained within vesicles of the host cell, and each is derived from a cyanobacterium, though not the same type of cyanobacterium that gave rise to the chloroplasts of algae and plants.

The closest living relative of P. chromatophora is the heterotroph P. ovalis. P. ovalis uses threadlike pseudopods to capture its prey, which it digests internally. Which of the following, if observed, would be the best reason for relabeling P. chromatophora as a mixotroph instead of an autotroph?

a pigmented central vacuole, surrounded by a nucleomorph
a vacuole with food inside
a contractile vacuole
a secretory vesicle

a vacuole with food inside

Use the following information to answer the question.

Giardia intestinalis is an intestinal parasite of humans and other mammals that causes intestinal ailments in most people who ingest the cysts. Upon ingestion, each cyst releases two motile cells, called trophozoites. These attach to the small intestine's lining via a ventral adhesive disk. The trophozoites anaerobically metabolize glucose from the host's intestinal contents to produce ATP. Reproduction is completely asexual, occurring by longitudinal binary fission of trophozoites, with each daughter cell receiving two haploid nuclei (n = 5). A trophozoite will often encyst as it passes into the large intestine by secreting around itself a case that is resistant to cold, heat, and dehydration. Infection usually occurs by drinking untreated water that contains cysts.

Given its mode of reproduction and internal structures, which of the following should be expected to occur in Giardia at some stage of its life cycle?

meiosis
crossing over
synapsis
separation (segregation) of daughter chromosomes

separation (segregation) of daughter chromosomes

Use the following information to answer the question(s) below.

Giardia intestinalis is an intestinal parasite of humans and other mammals that causes intestinal ailments in most people who ingest the cysts. Upon ingestion, each cyst releases two motile cells, called trophozoites. These attach to the small intestine's lining via a ventral adhesive disk. The trophozoites anaerobically metabolize glucose from the host's intestinal contents to produce ATP. Reproduction is completely asexual, occurring by longitudinal binary fission of trophozoites, with each daughter cell receiving two haploid nuclei (n = 5). A trophozoite will often encyst as it passes into the large intestine by secreting around itself a case that is resistant to cold, heat, and dehydration. Infection usually occurs by drinking untreated water that contains cysts.

If the mitosomes of Giardia contain no DNA, yet are descendants of what were once free-living organisms, then where are we likely to find the genes that encode their structures, and what accounts for their current location there?

plasmids; conjugation
plasmids; transformation
nucleus; S phase
nucleus; horizontal gene transfe

nucleus; horizontal gene transfer

Part A Part complete
Plasmodium exhibits consumption in its interactions with mosquitoes and humans. Which process is not an example of consumption?
Plasmodium exhibits consumption in its interactions with mosquitoes and humans. Which process is not an example of consumption?
Parasitism.
Herbivory.
Commensalism.
Predation.

Commensalism.

Which form of Plasmodium is the immediate cause of anemia in humans?
View Available Hint(s)
Which form of Plasmodium is the immediate cause of anemia in humans?
Merozoites.
Diploid zygote.
Sporozoites.
Gametocytes.

Merozoites

Which of the following statements about the Plasmodium parasite is true?
Which of the following statements about the Plasmodium parasite is true?
The diploid zygote undergoes meiosis and mitosis to produce haploid merozoites.
The diploid zygote moves from the infected human to the mosquito as part of the mosquito's blood meal.
Plasmodium cells in the mosquito's saliva target red blood cells in a human and produce offspring that infect liver cells.
Merozoites live off the hemoglobin and nutrients in red blood cells and divide to produce more merozoites, destroying red blood cells in the process.

Merozoites live off the hemoglobin and nutrients in red blood cells and divide to produce more merozoites, destroying red blood cells in the process.

How do humans combat infection by the Plasmodium parasite?
View Available Hint(s)
How do humans combat infection by the Plasmodium parasite?
Cytotoxic T cells secrete anticoagulant to kill infected red blood cells.
Cytotoxic T cells destroy infected liver cells by recognizing a Plasmodium protein bound to an HLA protein on the surface of those cells.
Plasmodium cells bind to liver cells that have the CP26 protein on their cell surface and form a complex that is targeted by cytotoxic T cells.
Liver cells secrete the HLA-B53 protein, which binds to and inactivates Plasmodium cells in the bloodstream.

Cytotoxic T cells destroy infected liver cells by recognizing a Plasmodium protein bound to an HLA protein on the surface of those cells.

The video describes a coevolutionary arms race between the Plasmodium parasite and its human hosts.
True or false? One example of a coevolutionary arms race is when faster deer evolve and favor wolves and cougars that have stronger eyesight and senses of smell.

The video describes a coevolutionary arms race between the Plasmodium parasite and its human hosts.
True or false? One example of a coevolutionary arms race is when faster deer evolve and favor wolves and cougars that have stronger eyesight and senses of smell.

True
False

True

A sign on the beach states, "Beach Closed. Red Tide." The organisms interfering with your use of this beach are probably _____. See Concept 28.3 (Page 602)
View Available Hint(s)
A sign on the beach states, "Beach Closed. Red Tide." The organisms interfering with your use of this beach are probably _____. See Concept 28.3 (Page 602)
amoebas
ciliates
diatoms
dinoflagellates
species of red algae

dinoflagellates

When a mosquito infected with Plasmodium first bites a human, the Plasmodium _____.
When a mosquito infected with Plasmodium first bites a human, the Plasmodium _____.
gametes fuse, forming an oocyst
cells cause lysing of the human red blood cells
oocyst undergoes meiosis
cells infect the human liver cells

cells infect the human liver cells

You are given the task of designing an aquatic protist that is a primary producer. It cannot swim on its own, yet must stay in well-lit surface waters. It must be resistant to physical damage from wave action. It should be most similar to a(n) _____.
red alga
apicomplexan
dinoflagellate
diatom

diatom

Which of the following have chloroplasts (or structures since evolved from chloroplasts) thought to be derived from ancestral green algae?
apicomplexans
chlorarachniophytes
dinoflagellates
stramenopiles

chlorarachniophytes

A biologist discovers an alga that is marine, multicellular, and lives at a depth reached only by blue light. This alga is most likely a type of _____.
green algae
brown algae
golden algae
red algae

red algae

Green algae differ from land plants in that many green algae _____.
have cell walls containing cellulose
are unicellular
have plastids
have alternation of generations

are unicellular

_____ are eukaryotic autotrophs that float near the surface of water and are the basis of the food chain. See Concept 28.6 (Page 612)
Zooplankton
Slime molds
Phytoplankton
Cyanobacteria
Symbionts

Phytoplankton

Coral bleaching, which causes high coral mortality, has been occurring widely in coral reefs. Coral bleaching actually refers to the death of symbiotic dinoflagellates living within the corals. Why does coral bleaching cause the corals to die? See Concept 28.6 (Page 612)
Dinoflagellates attract zooplankton and other prey that the corals eat.
Dinoflagellates secrete the calcium carbonate that forms the "exoskeleton" of coral animals.
Dinoflagellates protect the corals from pathogenic bacteria.
Dinoflagellates protect the corals from UV radiation.
Dinoflagellates provide nutrients from the products of photosynthesis to the corals in exchange for a safe place to live.

Dinoflagellates provide nutrients from the products of photosynthesis to the corals in exchange for a safe place to live.

Use the following information to answer the question(s) below.

Healthy individuals of Paramecium bursaria contain photosynthetic algal endosymbionts of the genus Chlorella. When within their hosts, the algae are referred to as zoochlorellae. In aquaria with light coming from only one side, P. bursaria gather at the well-lit side, whereas other species of Paramecium gather at the opposite side. The zoochlorellae provide their hosts with glucose and oxygen, and P. bursaria provides its zoochlorellae with protection and motility. P. bursaria can lose its zoochlorellae in two ways: (1) if kept in darkness, the algae will die; and (2) if prey items (mostly bacteria) are absent from its habitat, P. bursaria will digest its zoochlorellae.

Which term most accurately describes the nutritional mode of healthy P. bursaria?
photoheterotroph
photoautotroph
chemoautotroph
mixotroph

mixotroph

Living diatoms contain brownish plastids. If global warming causes blooms of diatoms in the surface waters of Earth's oceans, how might this be harmful to the animals that build coral reefs?
The diatoms' photosynthetic output may over-oxygenate the water.
The coral animals' endosymbiotic dinoflagellates may get "shaded out" by the diatoms.
The coral animals may die from overeating the plentiful diatoms with their cases of silica.
The coral animals, which capture planktonic organisms, may be outcompeted by the diatoms.

The coral animals' endosymbiotic dinoflagellates may get "shaded out" by the diatoms.

Imagine that some members of an aquatic species of motile, photosynthetic protists evolve to become parasitic to fish. They gain the ability to live in the fish gut, absorbing nutrients as the fish digests food. Over time, which of the following phenotypic changes would you expect to observe in this population of protists?
gain of a rigid cell wall
loss of motility
loss of chloroplasts
gain of meiosis

loss of chloroplasts

Which of the following organisms is a producer?
ciliates
diatoms
kinetoplastids
apicomplexans

diatoms

Which of the following statements is accurate with regard to the observation that "income levels in countries hard hit by malaria are 33% lower than in similar countries free of the disease."
Which of the following statements is accurate with regard to the observation that "income levels in countries hard hit by malaria are 33% lower than in similar countries free of the disease."
The observation demonstrates that correlations provide excellent indications of causality.
This observation suggests that symptoms from malaria cause patients to lose pay because they miss work.
In order to understand the cause of this observation, scientists should eradicate malaria in ten countries but not in ten other comparable countries in order to experimentally test whether malaria caused the low income levels.
This observation is an example of a correlation and therefore causality cannot be inferred as confidently as if we have results from a manipulated experiment.

This observation is an example of a correlation and therefore causality cannot be inferred as confidently as if we have results from a manipulated experiment.

Which of the following results would be most likely if a layer of warm, light water caused by ocean surface warming blocks nutrient upwelling?
Which of the following results would be most likely if a layer of warm, light water caused by ocean surface warming blocks nutrient upwelling?
reduced populations of fish because they avoid warm water
increased populations of producers because fewer fish are produced, and they eat fewer producers
increased populations of producers because they have access to more CO2
reduced populations of producers because they have access to fewer nutrients

reduced populations of producers because they have access to fewer nutrients

Plastids that are surrounded by more than two membranes are evidence of
Plastids that are surrounded by more than two membranes are evidence of
budding of the plastids from the nuclear envelope.
secondary endosymbiosis.
origin of the plastids from archaea.
evolution from mitochondria.
fusion of plastids.

secondary endosymbiosis.

Biologists suspect that endosymbiosis gave rise to mitochondria before plastids partly because
mitochondrial proteins are synthesized on cytosolic ribosomes, whereas plastids utilize their own ribosomes.
the products of photosynthesis could not be metabolized without mitochondrial enzymes.
all eukaryotes have mitochondria (or their remnants), whereas many eukaryotes do not have plastids.
without mitochondrial CO2 production, photosynthesis could not occur.
mitochondrial DNA is less similar to prokaryotic DNA than is plastid DNA.

all eukaryotes have mitochondria (or their remnants), whereas many eukaryotes do not have plastids.

Which of the features below are found in all protist lineages?
Which of the features below are found in all protist lineages?
Plastids
Mitochondria
Organelles that arose by secondary endosymbiosis.

Mitochondria

Which of the following statements supports the hypothesis of an endosymbiotic origin of mitochondria?
Diplomonads have modified mitochondria called mitosomes.
Each mitochondrion has its own DNA molecule.
Some algae contain plastids surrounded by four membranes.

Each mitochondrion has its own DNA molecule.

Proteins consist of amino acids linked to

fatty acids.
phosphates.
other amino acids.
sugars.

Other amino acids

Which of the following is hydrophobic and therefore insoluble in water?

phospholipid
ribonucleotide
nucleotide
lipid

lipid

Animals obtain the energy they need for growth by

using ATP in food.
synthesizing macromolecules.
breaking down organic molecules.
recycling heat from the environment.

breaking down organic molecules.

The mammalian trachea and esophagus both connect to the

large intestine.
pharynx.
epiglottis.
rectum.
stomach.

pharynx

Which of the following organs is incorrectly paired with its function?
Which of the following organs is incorrectly paired with its function?
oral cavity-starch digestion
pancreas-enzyme production
small intestine-nutrient absorption
stomach-protein digestion
large intestine-bile production

large intestine-bile production

Which of the following is not a major activity of the stomach?
Which of the following is not a major activity of the stomach?
mucus secretion
enzyme secretion
nutrient absorption
HCl secretion
mechanical digestion

nutrient absorption

Consider the interior surface of the human stomach and its secretions, shown in the figure. Why doesn't gastric juice, composed of hydrochloric acid and a protease called pepsin, digest the cells that line the stomach?
The figure shows the interior surface of the human stomach and its secretions. Chief cells generate pepsinogen. Parietal cells generate Cl superscript minus sign and H superscript plus sign, which react to make HCl. HCl is used in a reaction with pepsinogen to produce pepsin, or the active enzyme.
Consider the interior surface of the human stomach and its secretions, shown in the figure. Why doesn't gastric juice, composed of hydrochloric acid and a protease called pepsin, digest the cells that line the stomach?

Digestion doesn't begin until the small intestine.
The stomach lining secretes mucus, a mixture of glycoproteins, cells, salts, and water.
Chief cells release pepsin in an inactive form. HCl in the stomach converts pepsin to an active form of the enzyme called pepsinogen by clipping off a small portion of the molecule to expose its active site.

The stomach lining secretes mucus, a mixture of glycoproteins, cells, salts, and water.

Select the correct statement about essential nutrients.
Essential nutrients must be obtained from diet.
Due to their biochemical sophistication, humans have to ingest fewer essential nutrients than do other animals.
All animals require an identical set of essential nutrients.

Essential nutrients must be obtained from diet.

Identify the roles played by human gut bacteria.
Ulcers are caused by the acid-tolerant bacterium Helicobacter pylori.
Human gut bacteria synthesize all essential vitamins required by humans.
The human appendix houses mutualistic bacteria that digest cellulose.

Ulcers are caused by the acid-tolerant bacterium Helicobacter pylori.

Bacteria in the human gut are which of the following?
Bacteria in the human gut are which of the following?
all pathogens
all mutualists
both pathogens and mutualists

both pathogens and mutualists

Many people have a tendency to gorge on rich, fatty foods. How could such a preference have evolved?
In ancestral hunter-gatherer communities, individuals with a tendency to gorge on such foods when available would have had a selective advantage.
Most people find fatty foods tasty and satisfying.
Fatty foods are very rich in calories and consuming them is an efficient way to gain weight.

In ancestral hunter-gatherer communities, individuals with a tendency to gorge on such foods when available would have had a selective advantage.

If you put the following events in the order they occur in the human digestive system, the third event in the series would be:
Partially digested food enters the small intestine.
Cells in gastric pits secrete protons.
Pepsin activates pepsinogen.
HCl activates pepsinogen.

Pepsin activates pepsinogen.

Mastering Biology Review #3 - Subjecto.com

Mastering Biology Review #3

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To survive, all animals must _____. See Concept 41.1
digest plant material
hibernate
balance consumption of food with use and storage of nutrients
ingest nutrients from the environment every day of their lives
have a complete digestive system

balance consumption of food with use and storage of nutrients

The "essential nutrients" for proper human nutrition include _____. See Concept 41.1 (Page 897)

calcium, sodium, potassium, and other minerals
active enzymes from plants and/or animals
glucose
all of the amino acids
cellulose

calcium, sodium, potassium, and other minerals

Birth defects of the neural tube in humans _____. See Concept 41.1 (Page 899)

are typically seen in 10-20% of male babies born in well-developed countries
are not affected by nutritional considerations during pregnancy
result from excess sodium in the pregnant woman’s diet
can be prevented by ingestion of more vitamin A during the periconception interval
are reduced from about 6% without folic acid supplements in the periconception interval to about 1% when the supplements were taken

are reduced from about 6% without folic acid supplements in the periconception interval to about 1% when the supplements were taken

The following table shows the contents of a multivitamin supplement and its percentage of recommended daily values (%DV).

The most likely reason that some of the vitamins and minerals in this supplement are found at less than 100% is that _____.

The following table shows the contents of a multivitamin supplement and its percentage of recommended daily values (%DV).

Dietary Supplement % DV
Vitamin A 70
Vitamin C 100
Vitamin D 100
Vitamin E 150
Vitamin K 13
Vitamin B1 100
Vitamin B2 100
Folic acid 100
Vitamin B12 41.7
Calcium 20
Phosphorus 5
Iodine 100
Magnesium 25
Zinc 100
Copper 100
Chromium 125
Molybdenum 100
Iron 0

The most likely reason that some of the vitamins and minerals in this supplement are found at less than 100% is that _____.
it is too easy to overdose on minerals such as phosphorus and calcium
it is dangerous to overdose on fat-soluble vitamins such as A and K
it would be chemically impossible to add more
these vitamins and minerals are too large in size to reach 100%

it is dangerous to overdose on fat-soluble vitamins such as A and K

Animals that migrate great distances would obtain the greatest energetic benefit of storing chemical energy as _____.
fats
minerals
proteins
carbohydrates

fats

There is much discussion in the media about protecting biodiversity. But does biodiversity really matter? Canadian and Swiss researchers wanted to know if the diversity of arbuscular mycorrhizal fungi (AMF) was important to the productivity of grasslands (M.G.A. van der Heijden, J. N. Klironomos, M. Ursic, P. Moutoglis, R. Streitwolf-Engel, T. Boler, A. Wiemken, and I. R. Sanders. 1998. Mycorrhizal fungal diversity determines plant biodiversity, ecosystem variability, and productivity. Nature 396:69-72). Specifically, they wanted to know if it mattered which specific AMF species were present, or just that some type of AMF was present. They grew various plants in combination with one of four AMF species (A, B, C, and D), no AMF species (O), or all four AMF species together (A + B + C + D); and they measured plant growth under each set of conditions. All plant species were grown in each plot, so they always competed with each other, with the only difference being which AMF species were present.
On the graphs, the x-axis labels indicate the number and identity of AMF species (bar 0 = no fungi; bars A – D = individual AMF species; bar A + B + C + D = all AMF species together). The y-axis indicates the amount (grams) of plant biomass for the species shown in italics above each graph.

Examine all four graphs and choose the plant species that grows best with a combination of AMF species.
Centaurium erythrea (graph d)
Carex flacca (graph a)
Lotus corniculatus (graph b)
Sanguisorba officinalis (graph c)

Lotus corniculatus (graph b)

If a mammal did not obtain enough iodine in its diet, you might expect ________.

a decrease in enzyme function
the animal to have weak bones
a decrease in muscle function
a decreased ability to produce thyroid hormones

a decreased ability to produce thyroid hormones

Lysine is an essential amino acid for animals. If an animal did not consume lysine in its diet, you might expect that the animal ________.

could not effectively make many necessary proteins
was a carnivore
would make lysine from other amino acids
would be very healthy

could not effectively make many necessary proteins

Which of the following is a difference between vitamins and minerals?

Minerals are obtained by an animal through dietary sources, but vitamins are made by the animal.
Vitamins and minerals are only obtained by digesting plants.
Vitamins are organic molecules, but minerals are inorganic molecules.
Vitamins are involved in regulating enzyme activity, but minerals are not.

Vitamins are organic molecules, but minerals are inorganic molecules.

Folic acid supplements have become especially important for pregnant women because ________.

the fetus makes high levels of folic acid
folic acid supplies vitamins that only pregnant women can use
folic acid deprivation is associated with neural tube defects in a fetus
folic acid deprivation is a cause of heart abnormalities in a newborn

folic acid deprivation is associated with neural tube defects in a fetus

Three groups of cyclists consumed three different types of diets: high-carbohydrate; a diet mixed in carbohydrates, fat, and protein; or a diet higher in protein and fat. The average time each group could spend cycling over a six-hour period is shown in the accompanying graph. What conclusion from the data would help an athlete or trainer improve performance?

Maintaining elevated blood sugar improves performance.
Endurance is entirely related to diet.
An early 50 percent drop in blood glucose is associated with improved endurance.
Diet is not at all related to endurance.

Maintaining elevated blood sugar improves performance.

Choose the list that presents the four stages of food processing in the order in which they naturally occur. See Concept 41.2 (Page 900)

absorption → digestion → ingestion → elimination
ingestion → absorption → elimination → digestion
ingestion → digestion → elimination → absorption
ingestion → digestion → absorption → elimination
digestion → ingestion → absorption → elimination

ingestion → digestion → absorption → elimination

The gastrovascular cavity differs from the alimentary canal in that only the gastrovascular cavity _____. See Concept 41.2 (Page 902)

absorbs food molecules but does not produce hydrolytic enzymes
functions in digestion but not absorption
has only a single opening
stores food but does not digest it
is capable of extracellular digestion

has only a single opening

An advantage of a complete digestive system over a gastrovascular cavity is that the complete system _____.

excludes the need for extracellular digestion
allows extensive branching
allows for specialized regions with specialized functions
facilitates intracellular digestion

allows for specialized regions with specialized functions

Because the foods eaten by animals are often composed largely of macromolecules, animals need to have mechanisms for _____.

regurgitation
enzymatic hydrolysis
dehydration synthesis
demineralization

enzymatic hydrolysis

Fat digestion yields fatty acids and glycerol, whereas protein digestion yields amino acids; both digestive processes _____.

use water molecules when breaking bonds (hydrolysis)
are catalyzed by the same enzyme
require adenosine triphosphate (ATP) as an energy source
require the presence of hydrochloric acid to lower the pH

use water molecules when breaking bonds (hydrolysis)

Ticks are parasites that obtain nutrients by ingesting blood from a host animal. Ticks would be classified as ________.
filter feeders
substrate feeders
fluid feeders
bulk feeders

fluid feeders

The process of obtaining food is known as ________ and requires specialized feeding mechanisms.

excretion
absorption
ingestion
digestion

ingestion

In a hydra, digestion is completed ________.

extracellularly
in the gastrovascular cavity
intracellularly
in the alimentary canal

intracellularly

The process by which digested dietary substances cross cell membranes to be used by the body is known as ________.

absorption
digestion
ingestion
hydrolysis

absorption

Mechanical digestion, the process of breaking down large chunks of food into smaller pieces, is important because smaller pieces of food ________.

are more easily stored in the stomach than are larger pieces of food
are easier to excrete than are larger pieces of food
do not taste as good as larger pieces of food
have more surface area for chemical digestion than do larger pieces of food

have more surface area for chemical digestion than do larger pieces of food

When digested, proteins are broken down into _____.

glycerol only
fatty acids only
monosaccharides
amino acids
both glycerol and fatty acids

amino acids

When digested, fats are broken down into _____.

glycerol only
fatty acids only
monosaccharides
amino acids
both glycerol and fatty acids

both glycerol and fatty acids

Starch is a type of _____.
a. disaccharide
b. nucleotide
c. polysaccharide
d. fatty acid
e. monosaccharide

polysaccharide

Your small intestine can absorb ____ without their being further digested.

starches
fats
proteins
fructoses
nucleic acids

fructoses

Which of these enzymes begins the breakdown of starch?
bile
disaccharidases
lipase
amylase
nucleases

amylase

Starch can be broken down into the disaccharide known as _____.
lactose
glucose
sucrose
fructose
maltose

maltose

Protein digestion begins in the _____.
mouth
esophagus
stomach
small intestine
large intestine

stomach

What is the main component of gastric juice?
inactive pepsin
amylase
hydrochloric acid
water
bile

water

_____ is secreted by the _____ and acts to emulsify _____ in the _____.
Lipase … small intestine … fats … small intestine
Trypsin … pancreas … fats … small intestine
Nucleases … pancreas … nucleic acids … stomach
Amylase … salivary glands … starch … stomach
Bile … liver … fats … small intestine

Bile … liver … fats … small intestine

What acid is responsible for stomach acidity?
hydrochloric acid
carbonic acid
sulfuric acid
acetic acid
sodium hydroxide

hydrochloric acid

Which structure is not part of the alimentary canal?
Mouth.
Esophagus.
Salivary glands.
Stomach.

Salivary glands.

Which process is not required for an animal to obtain energy from food?

Ingestion.
Secretion.
Digestion.
Excretion.

Excretion

True or false? One advantage of having a tube-like digestive tract is that digestion of all compounds can take place simultaneously down the tract.
True
False

False

True or False? The liver is a component of the alimentary canal.

False

Choose the correct statement from the list below.

Mechanical digestion of proteins is more important than chemical digestion.
Proteins that are consumed in the diet are absorbed as individual amino acids following digestion.
Protein digestion begins in the small intestine with the activation of trypsinogen to trypsin
The stomach has a high pH which allows for the activation of digestive enzymes.

Proteins that are consumed in the diet are absorbed as individual amino acids following digestion.

Choose the correct statement from the list below.

Bile salts from the gall bladder are essential to the digestion of carbohydrates.
Carbohydrate digestion begins in the mouth with salivary amylase.
Carbohydrate absorption occurs primarily in the large intestine.
Carbohydrates are fully digested after passage through the stomach .

Carbohydrate digestion begins in the mouth with salivary amylase.

Choose the correct statement from the list below.

Bile salts from the pancreas are essential to the digestion of fats
Fats are fully digested after passage through the mouth and stomach.
Fat digestion begins in the stomach with the activation of trypsinogen to trypsin.
Free fatty acid absorption occurs in the small intestine.

Free fatty acid absorption occurs in the small intestine.

1. A fat molecule is composed of two types of smaller molecules, including only one molecule of .

Glycerol

2. A fat molecule also includes one, two, or three fatty acid molecules.

fatty acid

3. A fat molecule with only one fatty acid is called a monoglyceride.

monoglyceride

4. A fat molecule with three fatty acids is called a triacylglycerol, or a triglyceride.

triglyceride

5. A fatty acid includes a carboxyl group (-COOH) at one end as well as a long hydrocarbon chain.

hydrocarbons

6. The hydrocarbon chains found in fats store a lot of energy. They also make fats hydrophobic, or insoluble in water.

hydrophobic

Calculate the surface area of the cylinder that forms the "sides" of the microvillus rod. Use 3.14 for

0.30 μm2

Now calculate the surface area of the hemispherical top of the microvillus rod. Use 3.14 for

0.02 μm2

Now use your answers from Parts A and B to calculate the entire surface area of one microvillus (in

0.32 μm2

Suppose there are 2.0 x 109 microvilli per cm2 of intestinal epithelium. Calculate the total surface area of the microvilli in one cm2 of intestinal epithelium.

6.4 cm2

What is the percent increase in absorptive surface of the intestine due to the microvilli?

540%

Which of the following is an example of positive feedback in the lumen of the stomach?

Pepsin digests molecules of pepsinogen, producing more pepsin.
Pepsin works best in the acidic environment produced by hydrochloric acid.
Chief cells secrete pepsinogen, which is a precursor to pepsin.
Hydrochloric acid converts pepsinogen to pepsin.

Pepsin digests molecules of pepsinogen, producing more pepsin.

How do hydrogen ions (H+) and chloride ions (Cl-) get into the lumen of the stomach?

H+ is actively transported from parietal cells into the lumen, while Cl- diffuses from parietal cells into the lumen.
Parietal cells actively transport hydrochloric acid (HCl) into the lumen, and HCl then dissociates into H+ and Cl-.
Both H+ and Cl- diffuse from parietal cells into the lumen.
Parietal cells actively transport both H+ and Cl- into the lumen.

H+ is actively transported from parietal cells into the lumen, while Cl- diffuses from parietal cells into the lumen.

A researcher added a mixture of animal proteins to a physiological buffer solution (pH 7.4) in a test tube incubated at 37°C. The researcher then added purified pepsin to the mixture, but even after several hours, the proteins were not digested. Which of the following would explain this result?

The temperature was too low.
Pepsin doesn’t digest animal proteins.
The pH was too high.
Pepsin must be converted to its active form, pepsinogen, which digests proteins.

The pH was too high.

What is one function of mucus in the lumen of the stomach?

It protects the epithelium from being digested by gastric juice.
It prevents H+ secreted by parietal cells from entering the lumen.
It prevents pepsinogen from digesting proteins inside chief cells.
It neutralizes HCl in the lumen.

It protects the epithelium from being digested by gastric juice.

The epithelium that lines the stomach has many deep infoldings, or pits. In what way do these pits function as glands?

They secrete the hormone pepsinogen into the blood.
They secrete food into the main chamber of the stomach.
They secrete a mixture of gastric juice and partially digested food into the small intestine.
They secrete gastric juice into the main chamber of the stomach.

They secrete gastric juice into the main chamber of the stomach.

Choose the correct anatomical sequence that presents the order in which food in the digestive system passes through. See Concept 41.3 (Page 903)

pharynx → esophagus → stomach → small intestine → large intestine
pharynx → small intestine → large intestine → stomach
esophagus → stomach → pharynx → small intestine
pharynx → stomach → esophagus → small intestine
esophagus → pharynx → stomach → small intestine

pharynx → esophagus → stomach → small intestine → large intestine

For ingested foods, the first opportunity for enzymatic digestion occurs in the _____. See Concept 41.3 (Page 903)

large intestine
stomach
pancreas
mouth
small intestine

mouth

The lower esophageal sphincter surrounds the upper opening into the stomach. If this sphincter failed to properly constrict, there might be a problem with _____. See Concept 41.3 (Page 905)

the movement of swallowed food into the trachea rather than into the esophagus
too rapid emptying from the stomach into the small intestine
too rapid emptying of the small intestine into the large intestine
regurgitation of acidic stomach contents into the esophagus, commonly called "heartburn"
the control of defecation

regurgitation of acidic stomach contents into the esophagus, commonly called "heartburn"

The large surface area in the gut directly facilitates _____.

absorption
temperature regulation
secretion
filtration

absorption

In the digestive system, peristalsis is _____.

smooth muscle contractions that move food along the esophagus
the transport of nutrients to the liver through the hepatic portal vessel
voluntary control of the rectal sphincters regulating defecation
a process of fat emulsification in the small intestine

smooth muscle contractions that move food along the esophagus

Among mammals, it is generally true that _____.

the epiglottis prevents swallowed food from entering the trachea
after leaving the oral cavity, the bolus enters the larynx
all types of foods begin their enzymatic digestion in the mouth
the trachea leads to the esophagus and then to the stomach

the epiglottis prevents swallowed food from entering the trachea

Stomach cells are moderately well adapted to the acidity and protein-digesting activities in the stomach by having _____.

Stomach cells are moderately well adapted to the acidity and protein-digesting activities in the stomach by having _____.
a thick, mucous secretion and active mitosis of epithelial cells
a sufficient colony of H. pylori
a high level of secretion of enzymes by chief cells
a cell wall impermeable to acid

a thick, mucous secretion and active mitosis of epithelial cells

Upon activation by stomach acidity, the secretions of the parietal cells _____.

initiate the mechanical digestion of lipids in the stomach
initiate the chemical digestion of lipids in the stomach
delay digestion until the food arrives in the small intestine
initiate the chemical digestion of protein in the stomach

initiate the chemical digestion of protein in the stomach

Jahasz-Pocsine and co-workers found a correlation between gastric bypass surgery and neurological complications. Surgeons performed gastric bypass surgery on 150 patients at the University of Arkansas for Medical Sciences Neurology Clinic. Of the 150 patients, 26 experienced neurological complications related to the surgery. What is the most likely cause for the neurological complications?

sudden weight loss and caloric deficiency interfering with neurological function
nutrient (for example, vitamin and mineral) deficiencies
infections following surgical intervention
sloppy surgical technique of physicians performing the bypass surgery

nutrient (for example, vitamin and mineral) deficiencies

Over-the-counter medications for acid reflux or heartburn block the production of stomach acid. Which of the following cells are directly affected by this medication?

Over-the-counter medications for acid reflux or heartburn block the production of stomach acid. Which of the following cells are directly affected by this medication?
chief cells
parietal cells
goblet cells
smooth muscle cells

parietal cells

The bile salts _____.
emulsify fats in the duodenum
are enzymes
are manufactured by the pancreas
are normally an ingredient of gastric juice

emulsify fats in the duodenum

The absorption of fats differs from that of carbohydrates in that _____.

carbohydrates need to be emulsified before they can be digested, whereas fats do not
fats, but not carbohydrates, are digested by bacteria before absorption
fat absorption primarily occurs in the stomach, whereas carbohydrates are absorbed from the small intestine
most absorbed fat first enters the lymphatic system, whereas carbohydrates directly enter the blood

most absorbed fat first enters the lymphatic system, whereas carbohydrates directly enter the blood

Constipation can result from the consumption of a substance that _____.

speeds up movement of material in the large intestine
decreases water reabsorption in the small intestine
stimulates peristalsis
promotes water reabsorption in the large intestine

promotes water reabsorption in the large intestine

After surgical removal of an infected gallbladder, a person must be especially careful to restrict dietary intake of _____.

water
fat
sugar
protein

fat

If you place a small piece of a cracker on your tongue, what would you expect to happen?

Salivary amylase degrades the starch from the cracker into maltose.
The vitamins in the cracker are immediately absorbed.
The proteins in the cracker begin to be digested.
The flavor becomes less noticeable because the sugars are digested.

Salivary amylase degrades the starch from the cracker into maltose.

Examine the digestive system structures in the figure. The agents that help emulsify fats are produced in location ________.

9 (Liver)

Examine the digestive system structures in the figure. The highest rate of nutrient absorption occurs at location ________.

4

Examine the digestive system structures in the figure. Most of the digestion of fats occurs in structure(s) ________.

4 only (small intestine)

Which of the following organs is correctly paired with its function?

large intestine: bile production
small intestine: polysaccharide digestion
stomach: fat digestion
pancreas: starch digestion

small intestine: polysaccharide digestion

The function of chylomicrons is to ________.

transport lipids from the intestine to other organs
digest nucleic acids in the intestine
move proteins across plasma membranes of cells
break down carbohydrates in the mouth

transport lipids from the intestine to other organs

What is the importance of the mucus that are released by salivary glands?

They aid in degradation of triglycerides to fatty acids and monoglycerides.
They are hormonal molecules that stimulate the release of gastric juice by the stomach in anticipation of receipt of the contents of the mouth.
They are glycoproteins that make food slippery enough to slide easily through the esophagus.
They are beginning the process of starch digestion.

They are glycoproteins that make food slippery enough to slide easily through the esophagus.

Why do the cells of the digestive system secrete proteolytic enzymes, such as pepsin, in their inactive forms?

Inactive pepsin and trypsin are more easily transported across the cell membrane
These proteolytic enzymes, in active form, would digest the very tissues that synthesize them.
By secreting inactive enzymes, the catalytic activity of the enzymes is maintained for a longer time.
The stomach is too acidic to maintain these enzymes in their active form.

These proteolytic enzymes, in active form, would digest the very tissues that synthesize them.

The active ingredient orlistat acts to decrease the amount of fat that is absorbed by attaching to enzymes that digest fat. Which of the following are potential targets of orlistat?

salivary amylase
pepsidase
pancreatic lipase
secretin

pancreatic lipase

The digestion of ________ begins in the stomach.

fat
carbohydrates
nucleic acids
protein

protein

Nutrient-rich blood from the intestine is carried through the ________ to the liver.
lacteal vessels
lymphatic system
hepatic portal vein
hepatic portal artery

hepatic portal vein

Pepsinogen is converted to its active form in the stomach by ________.

HCl
parietal cells
chief cells
high pH conditions

HCl

Different types of food are eaten by various groups of animals, but it is usually true that _____. See Concept 41.4 (Page 909)

the teeth of herbivores tend to be sharper than the teeth of carnivores
animals typically produce enzymes that hydrolyze cellulose
the intestines of carnivores tend to be longer than the intestines of herbivores of similar overall body size
many carnivorous vertebrates house large populations of symbiotic bacteria and protists in special fermentation chambers in their stomachs
cellulose digestion in ruminant mammals occurs before the ingested foods reach the small intestine

cellulose digestion in ruminant mammals occurs before the ingested foods reach the small intestine

A relatively long cecum is characteristic of animals that are_____.

autotrophs
omnivores
herbivores
carnivores

herbivores

Cattle are able to survive on a diet consisting almost entirely of plant material because cattle _____.

are autotrophic
re-ingest their feces
manufacture all fifteen amino acids out of sugars in the liver
have cellulose-digesting, symbiotic microorganisms in chambers of their stomachs

have cellulose-digesting, symbiotic microorganisms in chambers of their stomachs

Coprophagy is important for the nutritional balance of _____.

rabbits and their relatives
insects and arthropods
ruminants such as cows
squirrels and some rodents

rabbits and their relatives

If you found a vertebrate skull in the woods and the teeth were sharp and scissor-like, what type of food would you expect this animal to eat?

flesh of another animal
nectar
blood
grass

flesh of another animal

Examine the digestive system structures in the figure. Bacteria that produce vitamins are found in the greatest concentration in location ________.

5 (large intestine)

Animals cannot produce enzymes to digest cellulose, yet many termite species consume cellulose from plant material as a main part of their diet. How do termites access the nutrients contained in cellulose?

Cellulose is digested intracellularly in the termite hindgut.
Mutualistic bacteria in the hindgut of the termite digest the cellulose into sugars.
The ingested plant material also contains enzymes for cellulose digestion.
Termites have specialized mouthparts to mechanically break down the cellulose.

Mutualistic bacteria in the hindgut of the termite digest the cellulose into sugars.

A zoologist analyzes the jawbones of an extinct mammal and concludes that it was an herbivore. The zoologist most likely came to this conclusion based upon the ________.

size of the mouth opening
position of muscle attachment sites
angle of the teeth in the mouth
shape of the teeth

shape of the teeth

What benefit is gained by intestinal bacteria living in a mutualistic relationship with an animal?

The bacteria can avoid the animal’s immune system.
Temperature is always regulated.
The bacteria can easily infect the animal’s intestinal cells.
The bacteria are provided with a regular source of nutrients.

The bacteria are provided with a regular source of nutrients.

When used appropriately, antibiotic treatment can effectively reduce bacteria populations and help fight infections. However, antibiotic treatments can have unintended effects. What is one concern when using antibiotics?

Antibiotics may also kill the beneficial bacteria of the microbiome, thereby disrupting digestive health.
Each antibiotic is only effective against one type of bacteria, so effects on infection are limited.
Antibiotics cause viruses to become more effective at infecting cells.
Antibiotics also damage animal cells, so they can be more harmful than a bacterial infection.

Antibiotics may also kill the beneficial bacteria of the microbiome, thereby disrupting digestive health.

A significant contribution of intestinal bacteria to human nutrition is the benefit of bacterial ________.

recovery of water from fecal matter
production of vitamins A and C
production of vitamin K
absorption of organic materials

production of vitamin K

Locate the pie chart showing the microbiome of a healthy adult’s intestinal tract. Which statement best represents the bacterial community composition of a healthy adult’s intestinal tract?

Firmicutes are the most abundant bacteria in the intestinal tract of healthy adults, followed by roughly equal amounts of Bacteroidetes and Proteobacteria. Actinobacteria are also present in small amounts.
Firmicutes are the most abundant bacteria in the intestinal tract of healthy adults, followed by roughly equal amounts of Bacteroidetes and Actinobacteria. Proteobacteria are also present in small amounts.
Bacteroidetes are the most abundant bacteria in the intestinal tract of healthy adults, followed by Firmicutes and Other bacterial phyla. Proteobacteria are also present in small amounts.
Firmicutes are the most abundant bacteria in the intestinal tract of healthy adults, followed by Bacteroidetes and a small amount of Actinobacteria and Proteobacteria

Firmicutes are the most abundant bacteria in the intestinal tract of healthy adults, followed by Bacteroidetes and a small amount of Actinobacteria and Proteobacteria.

The graph here shows a comparison of the stomach microbiomes of healthy adults versus adults infected with Helicobacter pylori, a type of bacteria that has been linked to the formation of stomach ulcers.

Which statement best represents the bacterial community composition of a healthy adult’s stomach?

Proteobacteria and Actinobacteria are the most abundant bacteria in the stomach of healthy adults.
Proteobacteria are the most abundant bacteria in the stomach of healthy adults, followed by miniscule amounts of Firmicutes, Actinobacteria, and Bacteroidetes.
Actinobacteria are the most abundant bacteria in the stomach of healthy adults, followed by roughly equal amounts of Bacteroidetes and Proteobacteria.
Actinobacteria are the most abundant bacteria in the stomach of healthy adults, followed by Firmicutes, and roughly equal amounts of Bacteroidetes and Proteobacteria.

Actinobacteria are the most abundant bacteria in the stomach of healthy adults, followed by Firmicutes, and roughly equal amounts of Bacteroidetes and Proteobacteria.

Compare the relative abundance of Actinobacteria in the microbiome of a healthy adult’s intestinal tract to that of a healthy adult’s stomach. Which statement best represents the relative abundance of Actinobacteria in each?

Actinobacteria are rare in both the stomach and intestinal tract of healthy adults.
Actinobacteria are rare in the stomach, but abundant in the intestinal tract of healthy adults.
Actinobacteria are abundant in both the stomach and intestinal tract of healthy adults.
Actinobacteria are abundant in the stomach, but rare in the intestinal tract of healthy adults.

Actinobacteria are abundant in the stomach, but rare in the intestinal tract of healthy adults.

Secretin stimulates the _____ to secrete _____.

pancreas … bicarbonate

Cholecystokinin (CCK) stimulates the _____ to secrete _____.

pancreas … pancreatic enzymes

The acidity of the stomach contents triggers the small intestine to secrete a hormone known as _____.

secretin

The presence of fatty acids and amino acids in the chyme from the stomach triggers the small intestine to secrete a hormone known as _____.

cholecystokinin, or CCK

Bile is produced by the _____ and stored by the _____ until it is secreted into the small intestine.

liver … gall bladder

What are the roles of the ob and db genes in appetite regulation?
In this experiment, mice of specific genotypes were paired together.
Which of the following statements about the genotype pairings is correct?
Which of the following statements about the genotype pairings is correct?

Pairing (b) joined two mice that were mutants for the ob gene but wild-type for the db gene.

In what way did pairing (a) serve as a unique experimental control?

Only in pairing (a) were both mice wild-type for both genes.

Based on the data shown in the table, which of the following is a reasonable conclusion about the wild-type gene products?

The ob+ gene product circulated between both mice in a pair, even when only one mouse was wild-type for that gene.

What effect does the ob+ gene product appear to have on appetite?

The ob+ gene product suppresses appetite.

Which of these hypotheses could explain the result for pairing (d)?

The db+ gene product is the receptor for the ob+ satiety factor; the db mutant in pairing (d) cannot receive this receptor through the circulation and therefore overproduces the ob+ satiety factor.

If the results had been identical for pairings (a) and (b), what conclusion would you have drawn?

Differences in ob genotype do not affect the change in body mass of the mice.

At point A on the graph, how would the body respond?
Take insulin into the body’s cells.
Take glycogen into the body’s cells.
Secrete insulin.
Break down glycogen in liver cells

Secrete insulin.

How do glucagon and insulin differ?

Insulin is secreted when the blood glucose level is low, whereas glucagon is secreted when the blood glucose level is high.
Insulin is secreted from the pancreas, whereas glucagon is secreted from the liver.
Insulin causes some cells to take up glucose, whereas glucagon causes some cells to secrete glucose.
Insulin acts only on skeletal muscle cells, whereas glucagon acts only on liver cells.

Insulin causes some cells to take up glucose, whereas glucagon causes some cells to secrete glucose.

Which of the following hypothetical situations might result in a blood sugar level that is too high?

An individual’s insulin receptors are defective. An individual has an autoimmune disorder that destroys the beta cells of the pancreas.

Among humans, increased interest in food intake normally occurs _____. See Concept 41.5 (Page 915)

via chemical signals released when the stomach is empty
via chemical signals related to the amount of glucose stored in the liver and muscle cells
only after the production of glucose in the liver can no longer meet metabolic needs
when fewer calories are taken in than are expended, but only after the body depletes its reserves of fat in the liver
via chemical signals related to the amount of protein stores in the liver

via chemical signals released when the stomach is empty

Obesity in humans is most clearly linked to _____.

type 2 diabetes and cardiovascular disease
type 1 diabetes and prostate cancer
type 2 diabetes and muscle hypertrophy
type 2 diabetes and decreased appetite

type 2 diabetes and cardiovascular disease

If you were to jog one kilometer a few hours after lunch, which stored fuel would you probably tap?

muscle proteins
fat stored in adipose tissue
liver glycogen and muscle glycogen
blood proteins

liver glycogen and muscle glycogen

When the digestion and absorption of organic carbohydrates results in more energy-rich molecules than are immediately required by an animal, the excess is _____.

stored as glycogen in the liver and muscles
eliminated in the feces
oxidized and converted to ATP
stored as starch in the liver

stored as glycogen in the liver and muscles

Food being digested in the stomach is in a highly acidic environment. When the food is released from the stomach into the small intestine, why is the environment no longer acidic?

Trypsinogen is activated, thus neutralizing the stomach acid.
Secretin increases the flow of bicarbonate ions from the pancreas into the small intestine to neutralize the stomach acid.
When pepsinogen activates pepsin, one result is the neutralization of stomach acid in the stomach.
Bile salts from the gallbladder neutralize the stomach acid.

Secretin increases the flow of bicarbonate ions from the pancreas into the small intestine to neutralize the stomach acid.

The Pimas are a group of people living in the southwestern United States and Mexico. Although Pima Indians living in the United States and Mexico have a similar genetic background, a five-fold increase in the incidence of type II diabetes mellitus among U.S. Pima has been reported. The body mass index of Mexicans of non-Pima descent, Mexicans of Pima descent, and Pimas living in the United States is shown in the figure. Based on this information and the graph, what can you infer about the incidence of type II diabetes mellitus?

The incidence of type II diabetes mellitus has increased in the past ten years.
People who develop type II diabetes mellitus are typically diagnosed in childhood or adolescence.
If you maintain a normal body weight (body mass index less than 25), you will not get type II diabetes mellitus.
Obesity is a risk factor for development of type II diabetes mellitus.

Obesity is a risk factor for development of type II diabetes mellitus.

In a healthy person, after a carbohydrate-rich meal, the production of ________ will increase, causing the uptake of ________ from the blood into liver cells.
In a healthy person, after a carbohydrate-rich meal, the production of ________ will increase, causing the uptake of ________ from the blood into liver cells.
insulin; glucagon
glucagon; glucose
insulin; glucose
glucagon; protein

insulin; glucose

If there is a strong genetic link for type II diabetes mellitus in your family, how might you minimize your risk of developing the disorder?

take oral insulin daily
eat complex carbohydrates like starch instead of sweets
maintain a healthy weight, eat a balanced diet, and exercise
monitor your blood glucose levels daily

maintain a healthy weight, eat a balanced diet, and exercise

A fasting animal whose energy needs exceed those provided in its diet will draw on its stored resources in which order?

fat, then glycogen, then protein
liver glycogen, then muscle glycogen, then fat
muscle glycogen, then fat, then liver glycogen
glycogen, then protein, then fat

liver glycogen, then muscle glycogen, then fat

Feelings of hunger can be stimulated by the hormone ________, but suppressed by the hormone ________.

secretin; gastrin
pepsin; trypsin
insulin; glucagon
ghrelin; PYY

ghrelin; PYY

The body tissue that consists largely of material located outside of cells is

epithelial tissue.
connective tissue.
smooth muscle.
skeletal muscle.
nervous tissue.

connective tissue.

Which of the following would increase the rate of heat exchange between an animal and its environment?

feathers or fur
blubber or fat layer
vasoconstriction
countercurrent heat exchanger
wind blowing across the body surface

wind blowing across the body surface

Consider the energy budgets for a human, an elephant, a penguin, a mouse, and a snake. The __________ would have the highest total annual energy expenditure, and the __________ would have the highest energy expenditure per unit mass.

elephant; mouse

Compared with a smaller cell, a larger cell of the same shape has

a smaller cytoplasm-to-nucleus ratio.
a smaller average distance between its mitochondria and the external source of oxygen.
less surface area per unit of volume.
the same surface-to-volume ratio.
less surface area.

less surface area per unit of volume.

An animal’s inputs of energy and materials would exceed its outputs
if it is hibernating.
if it is growing and increasing its mass.
if the animal is an endotherm, which must always take in more energy because of its high metabolic rate.
if it is actively foraging for food.
never; homeostasis makes these energy and material budgets always balance.

if it is growing and increasing its mass.

You are studying a large tropical reptile that has a high and relatively stable body temperature. How would you determine whether this animal is an endotherm or an ectotherm?
You note that its environment has a high and stable temperature. Because its body temperature matches the environmental temperature, you conclude that it is an ectotherm.
You know that it is an ectotherm because it is not a bird or mammal.
You know from its high and stable body temperature that it must be an endotherm.
You subject this reptile to various temperatures in the lab and find that its body temperature and metabolic rate change with the ambient temperature. You conclude that it is an ectotherm.
You measure the metabolic rate of the reptile, and because it is higher than that of a related species that lives in temperate forests, you conclude that this reptile is an endotherm and its relative is an ectotherm.

You subject this reptile to various temperatures in the lab and find that its body temperature and metabolic rate change with the ambient temperature. You conclude that it is an ectotherm.

Which of the following animals uses the largest percentage of its energy budget for homeostatic regulation?
a desert insect
a snake in a temperate forest
a hydra
a desert bird
a marine jelly (an invertebrate)

a desert bird

Select the correct statement describing feedback control in animals.
Ectotherms are regulators with respect to temperature.
Positive feedback loops contribute to homeostasis.
An animal may be a regulator for one environmental variable but a conformer for another.

An animal may be a regulator for one environmental variable but a conformer for another.

How do endotherms and ectotherms differ?
ndotherms are regulators and ectotherms are conformers.
Endotherms are warm-blooded and ectotherms are cold-blooded.
Endotherms and ectotherms differ in the means by which they regulate their body temperature.

Endotherms and ectotherms differ in the means by which they regulate their body temperature.

Look at the graphs and choose the correct statement describing the relationship between BMR (basal metabolic rate) and body mass of mammals. (Look carefully at the quantity being displayed on the y-axis of each figure.)
BMR is roughly proportional to body mass squared.
Large mammals have lower basal metabolic rates than small mammals.
Small mammals have lower BMR, but use more calories per kilogram than large mammals.

Small mammals have lower BMR, but use more calories per kilogram than large mammals.

Tunas, sharks, penguins, and dolphins all have a basic fusiform shape, tapered at both ends. What explains this similarity in shape?
All fast-swimming aquatic vertebrates have this shape.
The similarity is due to homology, based on shared ancestry.
The similarity is due to convergent evolution, because all these animals share similar environmental challenges.

The similarity is due to convergent evolution, because all these animals share similar environmental challenges.

Which statement about endotherms and ectotherms is correct?
Endothermy is a more successful strategy for thermoregulation than ectothermy.
Ectotherms are more abundant and diverse than endotherms.
Ectotherms are more primitive than endotherms.

Ectotherms are more abundant and diverse than endotherms.

Which of these is NOT one of the four major categories of tissue?

blood

What type of epithelium would you expect to find covering a surface subject to physical forces?
simple epithelium
squamous epithelium
stratified epithelium
simple cuboidal cells
columnar epithelium

stratified epithelium

What type of epithelial tissue, found in the intestines, absorbs nutrients?

simple columnar epithelium

Which of these tissues, found in the lungs, permits gas exchange by diffusion?

simple squamous epithelium

What type of epithelial tissue lines kidney tubules?

simple cuboidal cells

How does connective tissue differ from the other three major tissue types?

Connective tissue often consists of relatively few cells embedded in an extracellular matrix.

Which of these describes loose connective tissue?

It is a loose weave of fibers that functions as a packing material.

Cartilage is found _____.
surrounding organs such as the kidneys
in the heart
at the ends of bones such as the femur
covering the surface of your body
connecting one bone to another

at the ends of bones such as the femur

_____ is the connective tissue specialized for transport.
Bone
Blood
Adipose tissue
Muscle tissue
Cartilage

Blood

A neuron consists of _____.
a cell body only
dendrites only
axons only
dendrites, a cell body, and axons
striations

dendrites, a cell body, and axons

Nervous tissue functions _____.
as a physical barrier to the invasion of pathogens
to physically move the body
to sense stimuli
to physically support the body
in the absorption of nutrients

to sense stimuli

What type of muscle is responsible for contractions of the digestive tract and arteries?
smooth muscle
skeletal muscle
striated muscle
voluntary muscle
cardiac muscle

smooth muscle

Cardiac muscle is the only muscle composed of _____ fibers.

branched

_____ muscle is attached to bones.

Skeletal

Penguins, seals, and tuna have body forms that permit rapid swimming, because _____.

the shape is a convergent evolutionary solution, which reduces drag while swimming

Much of the coordination of vertebrate body functions via chemical signals is accomplished by the _____.
integumentary system
respiratory system
endocrine system
excretory system

endocrine system

Compared with a smaller cell, a larger cell of the same shape has _____.
a smaller average distance between its mitochondria and the external source of oxygen
a smaller cytoplasm-to-nucleus ratio
less surface area per unit of volume
less surface area

less surface area per unit of volume

All animals, whether large or small, have _____.
most of their cells in contact with an aqueous medium
an external body surface that is dry
a basic body plan that resembles a two-layered sac
a body surface covered with hair to keep them warm

most of their cells in contact with an aqueous medium

Most of the exchange surfaces of multicellular animals are lined with _____.

epithelial tissue
connective tissue
neural tissue
smooth muscle cells

epithelial tissue

Connective tissues typically have _____.

little space between the membranes of adjacent cells
the ability to shorten upon stimulation
relatively few cells and a large amount of extracellular matrix
the ability to transmit electrochemical impulses

relatively few cells and a large amount of extracellular matrix

Blood is best classified as connective tissue because _____.

it contains more than one type of cell
it is found within all the organs of the body
its cells are separated from each other by an extracellular matrix
its cells can move from place to place

its cells are separated from each other by an extracellular matrix

Most types of communication between cells utilize _____.

the exchange of cytosol between the cells
the exchange of DNA between the cells
chemical or electrical signals
the movement of the cells

chemical or electrical signals

All types of muscle tissue have _____.

cells that lengthen when appropriately stimulated
a response that can be consciously controlled
interactions between actin and myosin
striated banding patterns seen under the microscope

interactions between actin and myosin

Cardiac muscle cells are both _____.

smooth and under involuntary control
smooth and under voluntary control
striated and interconnected by intercalated disks
striated and under voluntary control

striated and interconnected by intercalated disks

Food moves along the digestive tract as the result of contractions by _____.

striated muscle
cardiac muscle
smooth muscle
skeletal muscle

smooth muscle

Which of the following is a true statement about body size and physiology?

The rate at which an animal uses nutrients and produces waste products is independent of its volume.
Small and large animals face different physiological challenges because an animal’s body mass increases cubically while its surface area increases as a squared function.
The amount of food and oxygen an animal requires and the amount of heat and waste it produces are inversely proportional to its mass.
The wastes produced by an animal double as its volume doubles and triple as its surface area triples.

Small and large animals face different physiological challenges because an animal’s body mass increases cubically while its surface area increases as a squared function.

An elephant and a mouse are running in full sunlight, and both overheat by the same amount above their normal body temperatures. When they move into the shade and rest, which animal will cool down faster?

The elephant will because it has the higher surface-area-to-volume ratio.
The mouse will because it has the higher surface-area-to-volume ratio.
They will cool at the same rate because they overheated by the same amount.
The elephant will because it has the lower surface-area-to-volume ratio.

The mouse will because it has the higher surface-area-to-volume ratio.

You have a cube of modeling clay in your hands. Which of the following changes to the shape of this cube of clay will decrease its surface area relative to its volume?

Stretch the cube into a long, shoebox shape.
Flatten the cube into a pancake shape.
Round the clay up into a sphere.
Pinch the edges of the cube into small folds.

Round the clay up into a sphere.

Part A Part complete
Which of the following is a correct statement about an organism and its environment? See Concept 40.1 (Page 872)
View Available Hint(s)

The gastrovascular cavity provides the nutrient exchange surface in mammals.
An animal is a closed system that is separate and distinct from its environment.
Animals isolated from their environments live longer than those exchanging matter with the environment.
The interstitial fluid is the exchange medium between body cells and the circulatory system in vertebrate animals.
None of the choices is correct.

The interstitial fluid is the exchange medium between body cells and the circulatory system in vertebrate animals.

The four major categories of tissues are _____. See Concept 40.1 (Page 874)
View Available Hint(s)

blood, nervous, connective, and muscle
muscle, epithelial, bone, and cartilage
simple squamous, simple cuboidal, simple columnar, and stratified squamous
nervous, epithelial, connective, and muscle
bone, muscle, blood, and adipose

nervous, epithelial, connective, and muscle

As animals have evolved large body size, they have also evolved adaptations to improve exchange of energy and materials with the environment. For example, in many larger organisms, evolution has favored lungs and a digestive tract with ________.

increased thickness
decreased blood supply
larger cells
more branching or folds

more branching or folds

Both the endocrine and nervous systems transmit information around an animal’s body. Which of the following is a characteristic of nervous system signals?

a voltage change must occur
allow gradual changes to take place in the body
travel quickly, allowing rapid transmission of signals
usually impact the entire body

travel quickly, allowing rapid transmission of signals

Some animals have no gills when young, but then develop gills that grow larger as the animal grows larger. What is the reason for this increase in gill size?

Relative to their surface area, the young have more body volume in which they can store oxygen for long periods of time.
The young of these animals are much more active than the adult, which leads to a higher BMR (basal metabolic rate) and, therefore, a higher need for oxygen.
Relative to their volume, the young have more surface area across which they can transport all the oxygen they need.
The young have a higher BMR.

Relative to their volume, the young have more surface area across which they can transport all the oxygen they need.

Evolutionary adaptations that help some animals directly exchange matter between the cells of their body and the environment include ________.

an unbranched internal surface, a small body size, and thick covering
a large body volume, a long, tubular body, and a set of wings
a gastrovascular cavity, a two-layered body, and a torpedo-like body shape
an external respiratory surface, a small body size, and a two-cell-layered body

an external respiratory surface, a small body size, and a two-cell-layered body

Interstitial fluid is ________.

identical to blood in composition.
found only in the lumen of the small intestine
the internal environment inside animal cells
a site of exchange between blood and body cells

a site of exchange between blood and body cells

Generally, epithelial cell layers are responsible for separating two fluids. For example, the epithelium of blood vessels in animals separates the blood from the interstitial fluid. What characteristic would you expect to see in an epithelium that was specialized for passive diffusion of materials from one fluid to another?

many layers of cells stacked together
a single layer of flattened cells
large, cube-shaped cells
loosely connected cells surrounded by an extracellular matrix

a single layer of flattened cells

In mammals, GH (growth hormone) is an endocrine signal that stimulates repair and growth of various tissues. Which of the following would be required for a tissue to respond to growth hormone?

a voltage change must occur
the presence of a growth hormone receptor on the responding tissue
nerve cells must attach to the responding tissue for growth hormone to work
the responding tissue must be muscle

the presence of a growth hormone receptor on the responding tissue

Muscle cells are organized to perform specific types of contractions within a tissue. Which of the following is a characteristic of smooth muscle?

spindle-shaped cells with a single nucleus
intercalated discs
striations with sarcomeres
many cells fused together

spindle-shaped cells with a single nucleus

In many animals, fat is stored in specialized cells in the ________.

muscle
adipose tissue
blood
bone

adipose tissue

Bone consists of ________.

many columnar epithelial cells packed together.
hardened fibrous connective tissue.
a mixture of hardened collagen and minerals.
chondroitin sulfate secreted by chondrocytes.

a mixture of hardened collagen and minerals.

What is the name of the epithelial cell surface that faces the outside of an organ?

lumen
interstitial
basal
apical

basal

Which organ system is responsible for protection against injury, infection, and dehydration?

Reproductive system
Excretory system
Integumentary system
Skeletal system

Integumentary system

The migratory eel, Anguilla rostrata, is born and lives the juvenile (immature) part of its life in a freshwater environment, but then migrates thousands of miles through the ocean as an adult in order to breed. These eels are known to regulate their internal water and salt balance. What adaptations would you expect this eel to have in order to transition from fresh water to salt water at these two life stages?

The juvenile eels would spend energy keeping water in their bodies.
The adult eels would spend energy keeping salt in their bodies.
The adult eels would be better at removing salt from their bodies compared to juveniles.
The juvenile eels would be better at removing salt from their bodies compared to adults.

The adult eels would be better at removing salt from their bodies compared to juveniles.

Which of these is an example of negative feedback?

As a blood clot begins to form, the process of its formation gets faster and faster.
After you eat, glucagon stimulates an increase in blood sugar levels.
After you eat, insulin stimulates the lowering of blood sugar levels.
The digestive enzyme pepsinogen is converted to pepsin by the action of hydrochloric acid; pepsin itself can then convert pepsinogen into pepsin.
Once labor begins, contractions increase in frequency and intensity.

After you eat, insulin stimulates the lowering of blood sugar levels.

Which term describes a steady state in which the internal conditions of an organism are kept within a narrow range without regard to the external conditions?
View Available Hint(s)

Regulatory homeostasis.
Negative feedback.
Thermoregulation.
Conformational homeostasis.

Regulatory homeostasis.

Which of the following actions is not a function of the epithelium?
View Available Hint(s)

Creates an internal environment that is different from the external environment.
Regulates the excretion of waste.
Controls the exchange of nutrients between the internal and external environments.
Allows the internal environment to alter its conditions to match those of the external environment.

Allows the internal environment to alter its conditions to match those of the external environment.

True or false? Organisms must maintain homeostasis because optimal enzyme activity is achieved within a very narrow range of conditions.
View Available Hint(s)

True
False

True

Which component of a homeostatic system compares sensory information to a target value?
View Available Hint(s)

Effector.
Integrator.
Set point.
Sensor.

Integrator.

Which component of a homeostatic system perceives changes in some parameter of the environment?
View Available Hint(s)

Set point.
Sensor.
Effector.
Integrator.

Sensor.

Which of the following actions acts to warm a homeothermic body?
View Available Hint(s)

Dilating blood vessels.
Panting.
Shivering.
Sweating.

Shivering.

Which of the following statements describes a negative feedback response?
View Available Hint(s)

The onset of contractions during childbirth stimulates the release of a hormone that stimulates further contractions.
After a meal, blood sugar levels in the body rise; insulin is secreted to lower blood sugar levels.
The arrival of platelets at a wound site stimulates the recruitment of more platelets to form a clot.
A person who loses 3 pounds continues to diet to lose an additional 10 pounds.

After a meal, blood sugar levels in the body rise; insulin is secreted to lower blood sugar levels.

When the body’s blood glucose level rises, the pancreas secretes insulin and, as a result, the blood glucose level declines. When the blood glucose level is low, the pancreas secretes glucagon and, as a result, the blood glucose level rises. Such regulation of the blood glucose level is the result of _____.

positive feedback
protein-protein interactions
catalytic feedback
negative feedback

negative feedback

You discover a new species of bacteria that grows in aquatic environments with high salt levels. While studying these bacteria, you note that their internal environment is similar to the salt concentrations in their surroundings. You also discover that the internal salt concentrations of the bacteria change as the salt concentration in their environment changes. The new species can tolerate small changes in this way, but dies from large changes because it has no mechanism for altering its own internal salt levels. What type of homeostatic mechanism is this species using to regulate its internal salt levels?

regulation
integration
assimilation
conformation

conformation

Homeostasis is the _____. See Concept 40.2 (Page 879)
View Available Hint(s)

idea that all vertebrates are built in a similar way
correlation of structure and function
cooperation of body parts to form tissues, organs, and systems
exchange of materials with the surrounding environment
maintenance of a relatively constant and optimal internal environment

maintenance of a relatively constant and optimal internal environment

Negative feedback is a method of homeostatic control that _____. See Concept 40.2 (Page 879)
View Available Hint(s)

operates independently of most signaling mechanisms
ensures that conditions in an organism do not vary too much above or below their set points
produces a response by lowering the set point of an organism’s metabolism
promotes decreases in metabolic rate rather than increases
increases the speed and rapidity of negative responses to environmental stimuli

ensures that conditions in an organism do not vary too much above or below their set points

In a physiological system operating with positive feedback, _____. See Concept 40.2 (Page 879)
View Available Hint(s)

a stimulus will initiate a response that returns the system to near its initial parameters
only an effector and control center are necessary to complete the control system
the range of acceptable values for a given parameter will be narrower than if the system were regulated by negative feedback
a change in a variable will amplify rather than reverse the change
a stimulus will prevent a small change from becoming too large

a change in a variable will amplify rather than reverse the change

The metamorphosis of a tadpole to an adult frog involves a thorough reconstruction of the animal’s body. All of the structural and physiological changes must be complete or the frog will not survive this transformation. Which type of regulation would ensure that the animal completed its transformation?

enzymatic catalysis
positive feedback
feedback inhibition
negative feedback

positive feedback

The body’s automatic tendency to maintain a constant and optimal internal environment is termed as ________.

static equilibrium
balanced equilibrium
homeostasis
physiological chance

homeostasis

An example of a properly functioning homeostatic control system is seen when ________.

the kidneys excrete salt into the urine when dietary salt levels rise
the core body temperature of a runner rises gradually from 37°C to 45°C
a blood cell shrinks when placed in a solution of salt and water
the blood pressure increases in response to an increase in blood volume

the kidneys excrete salt into the urine when dietary salt levels rise

a person were to travel to a time zone that was several hours ahead of their own, they may experience tiredness known as jet lag. Jet lag is due to a disruption of ________.

nerve impulses
homeostasis
circadian rhythm
body temperature

circadian rhythm

What would be an advantage for an animal that conforms to a changing environmental condition, such as temperature?

The animal’s internal temperature would remain constant, even though the external temperature had changed.
The animal would spend less energy regulating its internal temperature.
The animal would spend more time looking for food.
The animal’s internal temperature would change opposite to the change in the external temperature.

The animal would spend less energy regulating its internal temperature.

Chum salmon (Oncorhynchus keta) are born in freshwater environments and then migrate to the sea. Near the end of their lives, they return to the freshwater stream where they were born to spawn. In fresh water, water constantly diffuses into the body and ions are lost from the body. In salt water, body water diffuses out of the body and excess ions are gained from the water. A salmon’s gills have special cells to pump salt in or out of the body to maintain homeostasis. In response to the salmon’s moves between fresh water and salt water, some cells in the gills are produced and others are destroyed. These changes made in the cells of the gills during the lifetime of an individual salmon are an example of which of the following?

trade-off
evolution
acclimatization
adaptation

acclimatization

To prepare flight muscles for use on a cool morning, hawkmoths _____.

rapidly contract and relax these muscles to generate metabolic warmth
reduce the metabolic rate of the muscles to rest them before flight
relax the muscles completely until after they launch themselves into the air
decrease their standard metabolic rate

rapidly contract and relax these muscles to generate metabolic warmth

In a cool environment, an ectotherm is more likely to survive an extended period of food deprivation than would an equally sized endotherm because the ectotherm _____.

invests little energy in temperature regulation
expends more energy per kilogram of body mass than does the endotherm
has greater insulation on its body surface
maintains a higher basal metabolic rate

invests little energy in temperature regulation

An example of an ectothermic organism that has few or no behavioral options when it comes to its ability to adjust its body temperature is a _____.

honeybee in a hive on a rural farm
bass living in a farm pond
hummingbird flying through a prairie
sea star living deep in the ocean

sea star living deep in the ocean

The temperature-regulating center of vertebrate animals is located in the _____.

liver
thyroid gland
subcutaneous layer of the skin
hypothalamus

hypothalamus

Which of the following would increase the rate of heat exchange between an animal and its environment?

wind blowing across the body surface
feathers or fur
blubber or fat layer
vasoconstriction

wind blowing across the body surface

You are studying a large tropical reptile that has a high and relatively stable body temperature. How would you determine whether this animal is an endotherm or an ectotherm?

You note that its environment has a high and stable temperature. Because its body temperature matches the environmental temperature, you conclude that it is an ectotherm.
You know that it is an ectotherm because it is not a bird or mammal.
You know from its high and stable body temperature that it must be an endotherm.
You subject this reptile to various temperatures in the lab and find that its body temperature and metabolic rate change with the ambient temperature. You conclude that it is an ectotherm.

You subject this reptile to various temperatures in the lab and find that its body temperature and metabolic rate change with the ambient temperature. You conclude that it is an ectotherm.

A woman standing and watching the stars on a cool, calm night will lose most of her body heat by _____.

radiation
convection
conduction
evaporation

radiation

There are advantages and disadvantages to adaptations. Animals that are endothermic are likely to be at the greatest disadvantage in _____.

environments with a constant food source
very cold environments
environments with variable and limited food sources
very hot environments

environments with variable and limited food sources

Which principle of heat exchange is the most important explanation for why birds look larger in colder weather because they fluff their feathers?

Fluffing decreases the surface-area-to-volume ratio, thus decreasing the amount of heat lost to the environment.
Fluffing decreases the amount of heat lost by conduction when the bird makes contact with cold objects in its environment.
Fluffing creates a pocket of air near the bird that acts as insulation.
Fluffing feathers results in less cooling by radiation because feathers emit less infrared radiation than other tissues do.

Fluffing creates a pocket of air near the bird that acts as insulation.

What is the first thing that happens when body temperature increases above normal body temperature?

The thermostat in the hypothalamus activates cooling mechanisms.
Blood vessels in the skin constrict.
Sweat glands secrete sweat.
The thermostat in the blood vessels activates cooling mechanisms.

The thermostat in the hypothalamus activates cooling mechanisms.

Which of the following occurs when body temperature decreases below normal body temperature?

Skeletal muscles rapidly contract, cooling the body.
Sweat glands secrete sweat to cool the body.
Blood vessels in the skin constrict to help prevent heat loss.
Sweat glands secrete sweat to warm the body.

Blood vessels in the skin constrict to help prevent heat loss.

Which of the following primarily involves heat transfer by convection? See Concept 40.3 (Page 882)
View Available Hint(s)

The water in the lake is so cold that your legs become numb.
As you lie on the sand, you can feel the sun’s warm rays on your skin.
You roll down the car window to allow the cool breeze to blow through.
After sunset, you can feel heat from the warm pavement.
You sweat profusely as you mow the lawn on a hot summer day.

You roll down the car window to allow the cool breeze to blow through.

A countercurrent heat exchanger enables an animal to _____. See Concept 40.3 (Page 883)
View Available Hint(s)

slow metabolism when food is not available
reduce the loss of body heat to the environment
produce more heat when needed
increase heat loss by evaporation
absorb heat from the environment

reduce the loss of body heat to the environment

Bats and hummingbirds are examples of _____. See Concept 40.3 (Page 882)
View Available Hint(s)

ectotherms that are also poikilotherms
endotherms that are also poikilotherms
endotherms that are also homeotherms
ectotherms that are also homeotherms
endotherms that are also ectotherms

endotherms that are also poikilotherms

Elephants can often be observed cooling off by spraying water over their bodies with their trunks. What type of heat exchange is occurring?

evaporation
conduction
convection
radiation

evaporation

The panting responses observed in overheated birds and mammals dissipate excess heat by ________.

countercurrent exchange
acclimation
evaporation
vasoconstriction

evaporation

Most land-dwelling invertebrates and all of the amphibians ________.

become more active when environmental temperatures drop below 15°C
alter their metabolic rates to maintain a constant body temperature of 37°C
are ectothermic organisms with variable body temperatures
are endotherms but become thermo-conformers when they are in water

are ectothermic organisms with variable body temperatures

Part A Part complete
The metabolic breakdown of specialized brown fat deposits in certain animals is substantially increased during ________.

torpor
shivering thermogenesis
acclimatization
nonshivering thermogenesis

nonshivering thermogenesis

The use of brown fat to generate metabolic heat is mostly limited to small mammals. What is the basis of this adaptation?

Large mammals have lost their brown fat through the course of their evolution.
Small mammals cannot grow enough fur to insulate their bodies.
Small mammals do not have enough muscle to generate heat by shivering.
Because of their large surface area to volume ratio, heat loss across the body surface is higher in small animals.

Because of their large surface area to volume ratio, heat loss across the body surface is higher in small animals.

The thin horizontal arrows in the figure above show that the ________.

arterial blood is always cooler in the abdomen, compared to the temperature of the venous blood in the feet of the goose
warmer arterial blood transfers heat to the cooler venous blood
warmer arterial blood can bypass the legs as needed, when the legs are too cold to function well
warmer venous blood transfers heat to the cooler arterial blood

warmer arterial blood transfers heat to the cooler venous blood

The countercurrent arrangement of blood vessels is an adaptation that allows the goose to ________.
Use the figure to answer the following question.

A diagram shows circulation in the leg of a Canada goose. Blood in an artery is at 35 degrees Celsius, moving downward to the bottom of the leg. The temperature decreases to 30, 20, then 10 degrees Celsius. The blood vessel then curves back upwards, such that the vein passes alongside the artery. Heat transfer is shown by thin horizontal arrows, transferring from the artery to the vein. The blood in the vein increases from 9 to 18 to 27 and finally 33 degrees Celsius in the diagram. The warmed blood returns to the body.

The countercurrent arrangement of blood vessels is an adaptation that allows the goose to ________.
minimize heat exchange between the feet and water
generate heat using shivering thermogenesis
conserve heat in its core when the goose is swimming in cold water
more effectively cool off in the summer

conserve heat in its core when the goose is swimming in cold water

Based on graph (a), one observer suggests that a group of 100 ground squirrels would consume the same amount of oxygen per hour as 1 dog because 100 ground squirrels have the same total body mass as 1 dog. A second observer disagrees.
Who is correct?

The first observer is correct; 100 ground squirrels consume about 10 liters of oxygen per hour, the same amount as 1 dog.
The second observer is correct; 100 ground squirrels will consume less oxygen per hour than 1 dog.
The first observer is correct; 1 dog consumes about 3 liters of oxygen per hour, the same amount as 100 ground squirrels.
The second observer is correct; 100 ground squirrels will consume more oxygen per hour than 1 dog.

The second observer is correct; 100 ground squirrels will consume more oxygen per hour than 1 dog.

You can estimate the contribution of each wedge in a pie chart by remembering that the entire circle represents 100%, half is 50%, and so on.
What percent of the mouse’s energy budget goes to basal metabolism?

about 25%

What percent of the penguin’s budget is for activity?
What percent of the penguin’s budget is for activity?
about 10%
about 35%
almost 50%
almost 100%

almost 50%

Without considering the sizes of the wedges, how do the three pie charts differ in which functions they include?
Without considering the sizes of the wedges, how do the three pie charts differ in which functions they include?
The python chart is the only one that includes activity.
The penguin chart is the only one that includes thermoregulation.
Unlike the penguin and mouse charts, the python chart includes growth but does not include thermoregulation.
Unlike the mouse and python charts, the penguin chart does not include reproduction.

Unlike the penguin and mouse charts, the python chart includes growth but does not include thermoregulation.

Why does the pie chart for the python include growth but not thermoregulation?
Why does the pie chart for the python include growth but not thermoregulation?
The python grows throughout its life, and it is an ectotherm.
Only four variables can be shown in a pie chart, and growth is more important than thermoregulation in a python’s energy budget.
Energy used for thermoregulation could not be measured for the python.
The python grows throughout its life, but it does not thermoregulate.

The python grows throughout its life, and it is an ectotherm.

Does the penguin or the mouse expend a greater proportion of its energy budget on thermoregulation? Why?
Does the penguin or the mouse expend a greater proportion of its energy budget on thermoregulation? Why?
The penguin expends a greater proportion of its energy budget on thermoregulation because of its extremely cold Antarctic habitat.
The mouse expends a greater proportion of its energy budget on thermoregulation because of its small size.
The penguin expends a greater proportion of its energy budget on thermoregulation because of its large size.
The mouse expends a greater proportion of its energy budget on thermoregulation because of its temperate habitat.

The mouse expends a greater proportion of its energy budget on thermoregulation because of its small size.

Now look at the total annual energy expenditures for each animal.
How much more energy does the penguin expend each year compared to the similarly sized python?
How much more energy does the penguin expend each year compared to the similarly sized python?
The penguin expends 2 times as much energy as the python.
The penguin expends 42.5 times as much energy as the python.
The penguin expends 85 times as much energy as the python.
The penguin expends 332,000 times as much energy as the python.

The penguin expends 42.5 times as much energy as the python.

Which animal expends the most kilocalories per year on thermoregulation?
Which animal expends the most kilocalories per year on thermoregulation?
the mouse
the python
the penguin

the penguin

Given that adult penguins don’t grow from year to year, how would you explain this finding?
Given that adult penguins don’t grow from year to year, how would you explain this finding?
At certain times, penguins store considerable energy as fat, putting on weight in the process.
For several months after hatching, penguin chicks use a large proportion of the energy available to them to grow.
During the breeding season, penguins produce new biomass when they lay eggs and feed their chicks.
At certain times, penguins use up their fat stores, losing considerable weight.

At certain times, penguins store considerable energy as fat, putting on weight in the process.

Snake behavior in Wisconsin changes throughout the year. For example, a snake is _____.
Snake behavior in Wisconsin changes throughout the year. For example, a snake is _____.
less active in winter because the food supply is decreased
more active in summer because it can gain body heat by conduction
less active in winter because it does not need to avoid predators
more active in summer because that is the period for mating

more active in summer because it can gain body heat by conduction

Standard metabolic rate (SMR) and basal metabolic rate (BMR) are _____.
both measured across a wide range of temperatures for a given species
used differently: SMR is measured during exercise, whereas BMR is measured at rest
both measured in animals in a resting and fasting state
used to compare metabolic rates during feeding and other active conditions

both measured in animals in a resting and fasting state

Consider the energy budgets for a human, an elephant, a penguin, a mouse, and a snake. The _____ would have the highest total annual energy expenditure, and the _____ would have the highest energy expenditure per unit mass.
mouse; snake
elephant; human
human; penguin
elephant; mouse

elephant; mouse

Which of the following animals most likely uses the largest percentage of its energy budget for homeostatic regulation?
a bird living year round in a desert
a snake in a tropical forest
a shark swimming in the open ocean
a marine jelly (an invertebrate) living deep in the ocean

a bird living year round in a desert

Hummingbirds are small birds that require a regular food supply. When hummingbirds are faced with a situation that decreases their food supply, such as a storm, which of the following adaptations would be most useful for the bird to survive such an unpredictable and short-term absence of food resources?
hibernation
shivering
torpor
burrowing into soil

torpor

Metabolic rate is _____. See Concept 40.4 (Page 888)
typically higher in an ectothermic animal than in an endothermic one
directly proportional to body size
the total amount of energy an animal uses in a unit of time
the amount of heat gained by an animal in a unit of time
determined when the organism is vigorously exercising after consuming a fatty meal

the total amount of energy an animal uses in a unit of time

Choose the list that correctly ranks metabolic rates per gram of body mass, from lowest to highest. See Concept 40.4 (Page 889)
gazelle, lion, elephant
human, cat, mouse, salamander
fish, dog, mouse
human, rabbit, snake
hummingbird, dog, mouse

fish, dog, mouse

The metabolic rate of an animal is most accurately determined by ________.
the amount of carbon dioxide produced by an animal in a given time.
the amount of energy used by an animal in a given time
the amount of work done by an animal
the amount of food consumed during a meal

the amount of energy used by an animal in a given time

Independent of whether an organism is an endotherm or ectoderm, the least reliable indicator of an animal’s metabolic rate is the amount of ________.
water consumed in one day
food eaten in one day
heat generated in one day
oxygen used in mitochondria in one day

water consumed in one day

What can you determine from the graph?
A shrew uses more energy than an elephant.
A smaller animal would consume less food per gram of tissue.
An animal with a larger mass has a lower metabolic rate per gram of tissue relative to an animal with smaller mass.
An elephant uses more energy than a shrew.

An animal with a larger mass has a lower metabolic rate per gram of tissue relative to an animal with smaller mass.

A researcher is setting up an experiment to measure basal metabolic rate in prairie voles (Microtus ochrogastera small rodent). Which of the following would be the best set of conditions for the voles immediately before and during the measurement?
A researcher is setting up an experiment to measure basal metabolic rate in prairie voles (Microtus ochrogastera small rodent). Which of the following would be the best set of conditions for the voles immediately before and during the measurement?
House the animals in a cage with no food for a few hours before measurement; conduct measurements in a room the same temperature as the room where housed.
House the animals in a cage with plenty of food and water to avoid stress; conduct measurements in a room the same temperature as the room where housed.
House the animals in a cage with no food for a few hours before measurement; conduct measurements in a colder room than the room where housed, and exercise the voles.
House the animals in a cage with plenty of food and water to avoid stress; conduct measurements in a warmer room than the room where housed.

House the animals in a cage with no food for a few hours before measurement; conduct measurements in a room the same temperature as the room where housed.

Organisms maintain dynamic homeostasis through behavioral and physiological mechanisms. Which of the following statements is an accurate explanation of a negative feedback mechanism used by animals to regulate body temperature?
Squirrels are able to cool themselves during warmer months by producing more brown fat, which contains abundant mitochondria and a rich blood supply.
Desert jackrabbits have unusually large ears that serve as solar heat collectors to enable them to maintain their body temperatures.
A ground squirrel’s hypothalamus detects changes in environmental temperatures and responds by activating or suppressing metabolic heat production.
A goldfish slows its movements when the water temperature is lower.

A ground squirrel’s hypothalamus detects changes in environmental temperatures and responds by activating or suppressing metabolic heat production.

An emergent property belongs to
An emergent property belongs to
the parts of something but not the whole.
both the parts and the whole of something.
the newest part of something.
the whole of something but not its parts.

the whole of something but not its parts.

Imagine you have two sets of 8 blocks, each measuring 1 cm along each edge. You arrange one set into a large cube, 2 blocks × 2 blocks × 2 blocks. You arrange the other set into a straight beam, 1 block × 8 blocks. Compared with the beam, the large cube has
Imagine you have two sets of 8 blocks, each measuring 1 along each edge. You arrange one set into a large cube, 2 blocks 2 blocks 2 blocks. You arrange the other set into a straight beam, 1 block 8 blocks. Compared with the beam, the large cube has
the same volume and surface area.
the same volume but a smaller surface area.
a smaller volume and surface area.
a greater volume and surface area.

the same volume but a smaller surface area.

Natural selection refers to
the evolution of an individual organism.
the outcome of evolution.
a goal of evolution.
a mechanism of evolution.

a mechanism of evolution.

According to the hypothesis of serial endosymbiosis, which of the following was a key initial step in the origin of mitochondria?

A prokaryotic host cell engulfed an aerobic, photosynthetic bacterium.
A eukaryotic host cell engulfed an aerobic, photosynthetic bacterium.
A eukaryotic host cell engulfed an aerobic, heterotrophic bacterium.
A prokaryotic host cell engulfed an aerobic, heterotrophic bacterium.

A prokaryotic host cell engulfed an aerobic, heterotrophic bacterium.

Which of the following domains consists of all the organisms whose cells have true nuclei?

Bacteria
Animalia
Eukarya
Archaea

Eukarya

A diploid (2n) cell divides by meiosis, producing four daughter cells. Next, each daughter cell divides by mitosis, producing a total of eight granddaughter cells. Which of the following statements about the granddaughter cells is true?

Each granddaughter cell is haploid (n).

According to the endosymbiotic theory, why was it adaptive for the larger (host) cell to keep the engulfed cell alive, rather than digesting it as food?

The engulfed cell provided the host cell with carbon dioxide.
The engulfed cell allowed the host cell to metabolize glucose.
The engulfed cell provided the host cell with adenosine triphosphate (ATP).
The host cell was able to survive anaerobic conditions with the engulfed cell alive.

The engulfed cell provided the host cell with adenosine triphosphate (ATP).

The chloroplasts of land plants are thought to have been derived according to which evolutionary sequence?

cyanobacteria → red algae → green algae → land plants
cyanobacteria → green algae → fungi → land plants
cyanobacteria → green algae → land plants
red algae → brown algae → green algae → land plants

cyanobacteria → green algae → land plants

A particular species of protist has obtained a chloroplast via secondary endosymbiosis. You know this because the chloroplasts _____.

are exceptionally small
have only a single pigment
have nuclear and cyanobacterial genes
have three or four membranes

have three or four membranes

All protists are _____.

eukaryotic
symbionts
mixotrophic
unicellular

eukaryotic

An individual mixotroph loses its plastids, yet continues to survive. Which of the following most likely accounts for its continued survival?

It engulfs organic material by phagocytosis or by absorption.
It relies on photosystems that float freely in its cytosol.
It has an endospore.
It must have gained extra mitochondria when it lost its plastids.

It engulfs organic material by phagocytosis or by absorption.

Which process could have allowed the nucleomorphs of chlorarachniophytes to be reduced, without the net loss of any genetic information?

conjugation
horizontal gene transfer
meiosis
phagocytosis

horizontal gene transfer

Why has the kingdom Protista been abandoned? See Concept 28.1 (Page 592)
View Available Hint(s)

Some protists are multicellular.
The kingdom Protista is not monophyletic.
Some protists are more closely related to plants, animals, or fungi than they are to other protists.
Some protists are as small as prokaryotes.
The second and third answers are correct.

The second and third answers are correct.

Which of the following is true of secondary endosymbiosis? See Concept 28.1 (Page 593)
View Available Hint(s)

It is indicated by the presence of a double membrane surrounding the endymbiont.
An organism containing one endosymbiont engulfs another organism, and that organism becomes an endosymbiont.
It is indicated by the presence of a nucleomorph.
An organism containing an endosymbiont is engulfed by another organism and becomes an endosymbiont.
It is indicated by the presence of a mixotroph.

An organism containing an endosymbiont is engulfed by another organism and becomes an endosymbiont.

Use the following information to answer the question.

Paulinella chromatophora is one of the few cercozoans that is autotrophic, carrying out aerobic photosynthesis with its two elongated "chromatophores." The chromatophores are contained within vesicles of the host cell, and each is derived from a cyanobacterium, though not the same type of cyanobacterium that gave rise to the chloroplasts of algae and plants.

The closest living relative of P. chromatophora is the heterotroph P. ovalis. P. ovalis uses threadlike pseudopods to capture its prey, which it digests internally. Which of the following, if observed, would be the best reason for relabeling P. chromatophora as a mixotroph instead of an autotroph?

a pigmented central vacuole, surrounded by a nucleomorph
a vacuole with food inside
a contractile vacuole
a secretory vesicle

a vacuole with food inside

Use the following information to answer the question.

Giardia intestinalis is an intestinal parasite of humans and other mammals that causes intestinal ailments in most people who ingest the cysts. Upon ingestion, each cyst releases two motile cells, called trophozoites. These attach to the small intestine’s lining via a ventral adhesive disk. The trophozoites anaerobically metabolize glucose from the host’s intestinal contents to produce ATP. Reproduction is completely asexual, occurring by longitudinal binary fission of trophozoites, with each daughter cell receiving two haploid nuclei (n = 5). A trophozoite will often encyst as it passes into the large intestine by secreting around itself a case that is resistant to cold, heat, and dehydration. Infection usually occurs by drinking untreated water that contains cysts.

Given its mode of reproduction and internal structures, which of the following should be expected to occur in Giardia at some stage of its life cycle?

meiosis
crossing over
synapsis
separation (segregation) of daughter chromosomes

separation (segregation) of daughter chromosomes

Use the following information to answer the question(s) below.

Giardia intestinalis is an intestinal parasite of humans and other mammals that causes intestinal ailments in most people who ingest the cysts. Upon ingestion, each cyst releases two motile cells, called trophozoites. These attach to the small intestine’s lining via a ventral adhesive disk. The trophozoites anaerobically metabolize glucose from the host’s intestinal contents to produce ATP. Reproduction is completely asexual, occurring by longitudinal binary fission of trophozoites, with each daughter cell receiving two haploid nuclei (n = 5). A trophozoite will often encyst as it passes into the large intestine by secreting around itself a case that is resistant to cold, heat, and dehydration. Infection usually occurs by drinking untreated water that contains cysts.

If the mitosomes of Giardia contain no DNA, yet are descendants of what were once free-living organisms, then where are we likely to find the genes that encode their structures, and what accounts for their current location there?

plasmids; conjugation
plasmids; transformation
nucleus; S phase
nucleus; horizontal gene transfe

nucleus; horizontal gene transfer

Part A Part complete
Plasmodium exhibits consumption in its interactions with mosquitoes and humans. Which process is not an example of consumption?
Plasmodium exhibits consumption in its interactions with mosquitoes and humans. Which process is not an example of consumption?
Parasitism.
Herbivory.
Commensalism.
Predation.

Commensalism.

Which form of Plasmodium is the immediate cause of anemia in humans?
View Available Hint(s)
Which form of Plasmodium is the immediate cause of anemia in humans?
Merozoites.
Diploid zygote.
Sporozoites.
Gametocytes.

Merozoites

Which of the following statements about the Plasmodium parasite is true?
Which of the following statements about the Plasmodium parasite is true?
The diploid zygote undergoes meiosis and mitosis to produce haploid merozoites.
The diploid zygote moves from the infected human to the mosquito as part of the mosquito’s blood meal.
Plasmodium cells in the mosquito’s saliva target red blood cells in a human and produce offspring that infect liver cells.
Merozoites live off the hemoglobin and nutrients in red blood cells and divide to produce more merozoites, destroying red blood cells in the process.

Merozoites live off the hemoglobin and nutrients in red blood cells and divide to produce more merozoites, destroying red blood cells in the process.

How do humans combat infection by the Plasmodium parasite?
View Available Hint(s)
How do humans combat infection by the Plasmodium parasite?
Cytotoxic T cells secrete anticoagulant to kill infected red blood cells.
Cytotoxic T cells destroy infected liver cells by recognizing a Plasmodium protein bound to an HLA protein on the surface of those cells.
Plasmodium cells bind to liver cells that have the CP26 protein on their cell surface and form a complex that is targeted by cytotoxic T cells.
Liver cells secrete the HLA-B53 protein, which binds to and inactivates Plasmodium cells in the bloodstream.

Cytotoxic T cells destroy infected liver cells by recognizing a Plasmodium protein bound to an HLA protein on the surface of those cells.

The video describes a coevolutionary arms race between the Plasmodium parasite and its human hosts.
True or false? One example of a coevolutionary arms race is when faster deer evolve and favor wolves and cougars that have stronger eyesight and senses of smell.

The video describes a coevolutionary arms race between the Plasmodium parasite and its human hosts.
True or false? One example of a coevolutionary arms race is when faster deer evolve and favor wolves and cougars that have stronger eyesight and senses of smell.

True
False

True

A sign on the beach states, "Beach Closed. Red Tide." The organisms interfering with your use of this beach are probably _____. See Concept 28.3 (Page 602)
View Available Hint(s)
A sign on the beach states, "Beach Closed. Red Tide." The organisms interfering with your use of this beach are probably _____. See Concept 28.3 (Page 602)
amoebas
ciliates
diatoms
dinoflagellates
species of red algae

dinoflagellates

When a mosquito infected with Plasmodium first bites a human, the Plasmodium _____.
When a mosquito infected with Plasmodium first bites a human, the Plasmodium _____.
gametes fuse, forming an oocyst
cells cause lysing of the human red blood cells
oocyst undergoes meiosis
cells infect the human liver cells

cells infect the human liver cells

You are given the task of designing an aquatic protist that is a primary producer. It cannot swim on its own, yet must stay in well-lit surface waters. It must be resistant to physical damage from wave action. It should be most similar to a(n) _____.
red alga
apicomplexan
dinoflagellate
diatom

diatom

Which of the following have chloroplasts (or structures since evolved from chloroplasts) thought to be derived from ancestral green algae?
apicomplexans
chlorarachniophytes
dinoflagellates
stramenopiles

chlorarachniophytes

A biologist discovers an alga that is marine, multicellular, and lives at a depth reached only by blue light. This alga is most likely a type of _____.
green algae
brown algae
golden algae
red algae

red algae

Green algae differ from land plants in that many green algae _____.
have cell walls containing cellulose
are unicellular
have plastids
have alternation of generations

are unicellular

_____ are eukaryotic autotrophs that float near the surface of water and are the basis of the food chain. See Concept 28.6 (Page 612)
Zooplankton
Slime molds
Phytoplankton
Cyanobacteria
Symbionts

Phytoplankton

Coral bleaching, which causes high coral mortality, has been occurring widely in coral reefs. Coral bleaching actually refers to the death of symbiotic dinoflagellates living within the corals. Why does coral bleaching cause the corals to die? See Concept 28.6 (Page 612)
Dinoflagellates attract zooplankton and other prey that the corals eat.
Dinoflagellates secrete the calcium carbonate that forms the "exoskeleton" of coral animals.
Dinoflagellates protect the corals from pathogenic bacteria.
Dinoflagellates protect the corals from UV radiation.
Dinoflagellates provide nutrients from the products of photosynthesis to the corals in exchange for a safe place to live.

Dinoflagellates provide nutrients from the products of photosynthesis to the corals in exchange for a safe place to live.

Use the following information to answer the question(s) below.

Healthy individuals of Paramecium bursaria contain photosynthetic algal endosymbionts of the genus Chlorella. When within their hosts, the algae are referred to as zoochlorellae. In aquaria with light coming from only one side, P. bursaria gather at the well-lit side, whereas other species of Paramecium gather at the opposite side. The zoochlorellae provide their hosts with glucose and oxygen, and P. bursaria provides its zoochlorellae with protection and motility. P. bursaria can lose its zoochlorellae in two ways: (1) if kept in darkness, the algae will die; and (2) if prey items (mostly bacteria) are absent from its habitat, P. bursaria will digest its zoochlorellae.

Which term most accurately describes the nutritional mode of healthy P. bursaria?
photoheterotroph
photoautotroph
chemoautotroph
mixotroph

mixotroph

Living diatoms contain brownish plastids. If global warming causes blooms of diatoms in the surface waters of Earth’s oceans, how might this be harmful to the animals that build coral reefs?
The diatoms’ photosynthetic output may over-oxygenate the water.
The coral animals’ endosymbiotic dinoflagellates may get "shaded out" by the diatoms.
The coral animals may die from overeating the plentiful diatoms with their cases of silica.
The coral animals, which capture planktonic organisms, may be outcompeted by the diatoms.

The coral animals’ endosymbiotic dinoflagellates may get "shaded out" by the diatoms.

Imagine that some members of an aquatic species of motile, photosynthetic protists evolve to become parasitic to fish. They gain the ability to live in the fish gut, absorbing nutrients as the fish digests food. Over time, which of the following phenotypic changes would you expect to observe in this population of protists?
gain of a rigid cell wall
loss of motility
loss of chloroplasts
gain of meiosis

loss of chloroplasts

Which of the following organisms is a producer?
ciliates
diatoms
kinetoplastids
apicomplexans

diatoms

Which of the following statements is accurate with regard to the observation that "income levels in countries hard hit by malaria are 33% lower than in similar countries free of the disease."
Which of the following statements is accurate with regard to the observation that "income levels in countries hard hit by malaria are 33% lower than in similar countries free of the disease."
The observation demonstrates that correlations provide excellent indications of causality.
This observation suggests that symptoms from malaria cause patients to lose pay because they miss work.
In order to understand the cause of this observation, scientists should eradicate malaria in ten countries but not in ten other comparable countries in order to experimentally test whether malaria caused the low income levels.
This observation is an example of a correlation and therefore causality cannot be inferred as confidently as if we have results from a manipulated experiment.

This observation is an example of a correlation and therefore causality cannot be inferred as confidently as if we have results from a manipulated experiment.

Which of the following results would be most likely if a layer of warm, light water caused by ocean surface warming blocks nutrient upwelling?
Which of the following results would be most likely if a layer of warm, light water caused by ocean surface warming blocks nutrient upwelling?
reduced populations of fish because they avoid warm water
increased populations of producers because fewer fish are produced, and they eat fewer producers
increased populations of producers because they have access to more CO2
reduced populations of producers because they have access to fewer nutrients

reduced populations of producers because they have access to fewer nutrients

Plastids that are surrounded by more than two membranes are evidence of
Plastids that are surrounded by more than two membranes are evidence of
budding of the plastids from the nuclear envelope.
secondary endosymbiosis.
origin of the plastids from archaea.
evolution from mitochondria.
fusion of plastids.

secondary endosymbiosis.

Biologists suspect that endosymbiosis gave rise to mitochondria before plastids partly because
mitochondrial proteins are synthesized on cytosolic ribosomes, whereas plastids utilize their own ribosomes.
the products of photosynthesis could not be metabolized without mitochondrial enzymes.
all eukaryotes have mitochondria (or their remnants), whereas many eukaryotes do not have plastids.
without mitochondrial CO2 production, photosynthesis could not occur.
mitochondrial DNA is less similar to prokaryotic DNA than is plastid DNA.

all eukaryotes have mitochondria (or their remnants), whereas many eukaryotes do not have plastids.

Which of the features below are found in all protist lineages?
Which of the features below are found in all protist lineages?
Plastids
Mitochondria
Organelles that arose by secondary endosymbiosis.

Mitochondria

Which of the following statements supports the hypothesis of an endosymbiotic origin of mitochondria?
Diplomonads have modified mitochondria called mitosomes.
Each mitochondrion has its own DNA molecule.
Some algae contain plastids surrounded by four membranes.

Each mitochondrion has its own DNA molecule.

Proteins consist of amino acids linked to

fatty acids.
phosphates.
other amino acids.
sugars.

Other amino acids

Which of the following is hydrophobic and therefore insoluble in water?

phospholipid
ribonucleotide
nucleotide
lipid

lipid

Animals obtain the energy they need for growth by

using ATP in food.
synthesizing macromolecules.
breaking down organic molecules.
recycling heat from the environment.

breaking down organic molecules.

The mammalian trachea and esophagus both connect to the

large intestine.
pharynx.
epiglottis.
rectum.
stomach.

pharynx

Which of the following organs is incorrectly paired with its function?
Which of the following organs is incorrectly paired with its function?
oral cavity-starch digestion
pancreas-enzyme production
small intestine-nutrient absorption
stomach-protein digestion
large intestine-bile production

large intestine-bile production

Which of the following is not a major activity of the stomach?
Which of the following is not a major activity of the stomach?
mucus secretion
enzyme secretion
nutrient absorption
HCl secretion
mechanical digestion

nutrient absorption

Consider the interior surface of the human stomach and its secretions, shown in the figure. Why doesn’t gastric juice, composed of hydrochloric acid and a protease called pepsin, digest the cells that line the stomach?
The figure shows the interior surface of the human stomach and its secretions. Chief cells generate pepsinogen. Parietal cells generate Cl superscript minus sign and H superscript plus sign, which react to make HCl. HCl is used in a reaction with pepsinogen to produce pepsin, or the active enzyme.
Consider the interior surface of the human stomach and its secretions, shown in the figure. Why doesn’t gastric juice, composed of hydrochloric acid and a protease called pepsin, digest the cells that line the stomach?

Digestion doesn’t begin until the small intestine.
The stomach lining secretes mucus, a mixture of glycoproteins, cells, salts, and water.
Chief cells release pepsin in an inactive form. HCl in the stomach converts pepsin to an active form of the enzyme called pepsinogen by clipping off a small portion of the molecule to expose its active site.

The stomach lining secretes mucus, a mixture of glycoproteins, cells, salts, and water.

Select the correct statement about essential nutrients.
Essential nutrients must be obtained from diet.
Due to their biochemical sophistication, humans have to ingest fewer essential nutrients than do other animals.
All animals require an identical set of essential nutrients.

Essential nutrients must be obtained from diet.

Identify the roles played by human gut bacteria.
Ulcers are caused by the acid-tolerant bacterium Helicobacter pylori.
Human gut bacteria synthesize all essential vitamins required by humans.
The human appendix houses mutualistic bacteria that digest cellulose.

Ulcers are caused by the acid-tolerant bacterium Helicobacter pylori.

Bacteria in the human gut are which of the following?
Bacteria in the human gut are which of the following?
all pathogens
all mutualists
both pathogens and mutualists

both pathogens and mutualists

Many people have a tendency to gorge on rich, fatty foods. How could such a preference have evolved?
In ancestral hunter-gatherer communities, individuals with a tendency to gorge on such foods when available would have had a selective advantage.
Most people find fatty foods tasty and satisfying.
Fatty foods are very rich in calories and consuming them is an efficient way to gain weight.

In ancestral hunter-gatherer communities, individuals with a tendency to gorge on such foods when available would have had a selective advantage.

If you put the following events in the order they occur in the human digestive system, the third event in the series would be:
Partially digested food enters the small intestine.
Cells in gastric pits secrete protons.
Pepsin activates pepsinogen.
HCl activates pepsinogen.

Pepsin activates pepsinogen.

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