To survive, all animals must _____. See Concept 41.1 |
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 |
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 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 The most likely reason that some of the vitamins and minerals in this supplement are found at less than 100% is that _____. |
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 |
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. Examine all four graphs and choose the plant species that grows best with a combination of AMF species. |
Lotus corniculatus (graph b) |
If a mammal did not obtain enough iodine in its diet, you might expect ________. a decrease in enzyme function |
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 |
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 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 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. |
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 → 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 |
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 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 |
Fat digestion yields fatty acids and glycerol, whereas protein digestion yields amino acids; both digestive processes _____. use water molecules when breaking bonds (hydrolysis) |
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 ________. |
fluid feeders |
The process of obtaining food is known as ________ and requires specialized feeding mechanisms. excretion |
ingestion |
In a hydra, digestion is completed ________. extracellularly |
intracellularly |
The process by which digested dietary substances cross cell membranes to be used by the body is known as ________. absorption |
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 |
have more surface area for chemical digestion than do larger pieces of food |
When digested, proteins are broken down into _____. glycerol only |
amino acids |
When digested, fats are broken down into _____. glycerol only |
both glycerol and fatty acids |
Starch is a type of _____. |
polysaccharide |
Your small intestine can absorb ____ without their being further digested. starches |
fructoses |
Which of these enzymes begins the breakdown of starch? |
amylase |
Starch can be broken down into the disaccharide known as _____. |
maltose |
Protein digestion begins in the _____. |
stomach |
What is the main component of gastric juice? |
water |
_____ is secreted by the _____ and acts to emulsify _____ in the _____. |
Bile … liver … fats … small intestine |
What acid is responsible for stomach acidity? |
hydrochloric acid |
Which structure is not part of the alimentary canal? |
Salivary glands. |
Which process is not required for an animal to obtain energy from food? Ingestion. |
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. |
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. |
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. |
Choose the correct statement from the list below. Bile salts from the pancreas are essential to the digestion of fats |
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 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. |
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. |
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 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 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 → 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 |
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 |
regurgitation of acidic stomach contents into the esophagus, commonly called "heartburn" |
The large surface area in the gut directly facilitates _____. absorption |
absorption |
In the digestive system, peristalsis is _____. smooth muscle contractions that move food along the esophagus |
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 |
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 |
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 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 |
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? |
parietal cells |
The bile salts _____. |
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 |
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 |
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 |
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. |
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 |
The function of chylomicrons is to ________. transport lipids from the intestine to other organs |
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 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. |
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 |
pancreatic lipase |
The digestion of ________ begins in the stomach. fat |
protein |
Nutrient-rich blood from the intestine is carried through the ________ to the liver. |
hepatic portal vein |
Pepsinogen is converted to its active form in the stomach by ________. HCl |
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 |
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 |
herbivores |
Cattle are able to survive on a diet consisting almost entirely of plant material because cattle _____. are autotrophic |
have cellulose-digesting, symbiotic microorganisms in chambers of their stomachs |
Coprophagy is important for the nutritional balance of _____. rabbits and their relatives |
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 |
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. |
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 |
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. |
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. |
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 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 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. |
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 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? |
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? |
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 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 released when the stomach is empty |
Obesity in humans is most clearly linked to _____. type 2 diabetes and cardiovascular disease |
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 |
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 |
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. |
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. |
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. |
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 |
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 |
Feelings of hunger can be stimulated by the hormone ________, but suppressed by the hormone ________. secretin; gastrin |
ghrelin; PYY |
The body tissue that consists largely of material located outside of cells is epithelial tissue. |
connective tissue. |
Which of the following would increase the rate of heat exchange between an animal and its environment? feathers or fur |
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. |
less surface area per unit of volume. |
An animal’s inputs of energy and materials would exceed its outputs |
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 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 bird |
Select the correct statement describing feedback control in animals. |
An animal may be a regulator for one environmental variable but a conformer for another. |
How do endotherms and ectotherms differ? |
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.) |
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? |
The similarity is due to convergent evolution, because all these animals share similar environmental challenges. |
Which statement about endotherms and ectotherms is correct? |
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? |
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 _____. |
at the ends of bones such as the femur |
_____ is the connective tissue specialized for transport. |
Blood |
A neuron consists of _____. |
dendrites, a cell body, and axons |
Nervous tissue functions _____. |
to sense stimuli |
What type of muscle is responsible for contractions of the digestive tract and arteries? |
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 _____. |
endocrine system |
Compared with a smaller cell, a larger cell of the same shape has _____. |
less surface area per unit of volume |
All animals, whether large or small, have _____. |
most of their cells in contact with an aqueous medium |
Most of the exchange surfaces of multicellular animals are lined with _____. epithelial tissue |
epithelial tissue |
Connective tissues typically have _____. little space between the membranes of adjacent cells |
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 |
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 |
chemical or electrical signals |
All types of muscle tissue have _____. cells that lengthen when appropriately stimulated |
interactions between actin and myosin |
Cardiac muscle cells are both _____. smooth and under involuntary control |
striated and interconnected by intercalated disks |
Food moves along the digestive tract as the result of contractions by _____. striated 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. |
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. |
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. |
Round the clay up into a sphere. |
Part A Part complete The gastrovascular cavity provides the nutrient exchange surface in mammals. |
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) blood, nervous, connective, and muscle |
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 |
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 |
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. |
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 |
an external respiratory surface, a small body size, and a two-cell-layered body |
Interstitial fluid is ________. identical to blood in composition. |
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 |
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 |
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 |
spindle-shaped cells with a single nucleus |
In many animals, fat is stored in specialized cells in the ________. muscle |
adipose tissue |
Bone consists of ________. many columnar epithelial cells packed together. |
a mixture of hardened collagen and minerals. |
What is the name of the epithelial cell surface that faces the outside of an organ? lumen |
basal |
Which organ system is responsible for protection against injury, infection, and dehydration? Reproductive 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 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, 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? Regulatory homeostasis. |
Regulatory homeostasis. |
Which of the following actions is not a function of the epithelium? Creates an internal environment that is different from 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. True |
True |
Which component of a homeostatic system compares sensory information to a target value? Effector. |
Integrator. |
Which component of a homeostatic system perceives changes in some parameter of the environment? Set point. |
Sensor. |
Which of the following actions acts to warm a homeothermic body? Dilating blood vessels. |
Shivering. |
Which of the following statements describes a negative feedback response? 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. |
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 |
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 |
conformation |
Homeostasis is the _____. See Concept 40.2 (Page 879) idea that all vertebrates are built in a similar way |
maintenance of a relatively constant and optimal internal environment |
Negative feedback is a method of homeostatic control that _____. See Concept 40.2 (Page 879) operates independently of most signaling mechanisms |
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) a stimulus will initiate a response that returns the system to near its initial parameters |
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 |
The body’s automatic tendency to maintain a constant and optimal internal environment is termed as ________. static equilibrium |
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 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 |
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. |
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 |
acclimatization |
To prepare flight muscles for use on a cool morning, hawkmoths _____. rapidly contract and relax these muscles to generate metabolic warmth |
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 |
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 |
sea star living deep in the ocean |
The temperature-regulating center of vertebrate animals is located in the _____. liver |
hypothalamus |
Which of the following would increase the rate of heat exchange between an animal and its environment? wind blowing across the body surface |
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 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 |
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 |
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 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. |
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. |
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) The water in the lake is so cold that your legs become numb. |
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) slow metabolism when food is not available |
reduce the loss of body heat to the environment |
Bats and hummingbirds are examples of _____. See Concept 40.3 (Page 882) ectotherms that are also poikilotherms |
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 |
evaporation |
The panting responses observed in overheated birds and mammals dissipate excess heat by ________. countercurrent exchange |
evaporation |
Most land-dwelling invertebrates and all of the amphibians ________. become more active when environmental temperatures drop below 15°C |
are ectothermic organisms with variable body temperatures |
Part A Part complete torpor |
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. |
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 |
The countercurrent arrangement of blood vessels is an adaptation that allows the goose to ________. 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 ________. |
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. 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 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. |
about 25% |
What percent of the penguin’s budget is for activity? |
almost 50% |
Without considering the sizes of the wedges, how do the three pie charts differ in which functions they include? |
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? |
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? |
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. |
The penguin expends 42.5 times as much energy as the python. |
Which animal expends the most kilocalories per year on thermoregulation? |
the penguin |
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. |
Snake behavior in Wisconsin changes throughout the year. For example, a snake is _____. |
more active in summer because it can gain body heat by conduction |
Standard metabolic rate (SMR) and basal metabolic rate (BMR) are _____. |
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. |
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 |
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? |
torpor |
Metabolic rate is _____. See Concept 40.4 (Page 888) |
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) |
fish, dog, mouse |
The metabolic rate of an animal is most accurately determined by ________. |
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 |
What can you determine from the graph? |
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? |
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? |
A ground squirrel’s hypothalamus detects changes in environmental temperatures and responds by activating or suppressing metabolic heat production. |
An emergent property belongs to |
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 |
the same volume but a smaller surface area. |
Natural selection refers to |
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 prokaryotic host cell engulfed an aerobic, heterotrophic bacterium. |
Which of the following domains consists of all the organisms whose cells have true nuclei? Bacteria |
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 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 → land plants |
A particular species of protist has obtained a chloroplast via secondary endosymbiosis. You know this because the chloroplasts _____. are exceptionally small |
have three or four membranes |
All protists are _____. eukaryotic |
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 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 |
Why has the kingdom Protista been abandoned? See Concept 28.1 (Page 592) Some protists are multicellular. |
The second and third answers are correct. |
Which of the following is true of secondary endosymbiosis? See Concept 28.1 (Page 593) It is indicated by the presence of a double membrane surrounding the endymbiont. |
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 |
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 |
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 |
nucleus; horizontal gene transfer |
Part A Part complete |
Commensalism. |
Which form of Plasmodium is the immediate cause of anemia in humans? |
Merozoites |
Which of the following statements about the Plasmodium parasite is true? |
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? |
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. The video describes a coevolutionary arms race between the Plasmodium parasite and its human hosts. True |
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) |
dinoflagellates |
When a mosquito infected with Plasmodium first bites a human, the Plasmodium _____. |
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) _____. |
diatom |
Which of the following have chloroplasts (or structures since evolved from chloroplasts) thought to be derived from ancestral green algae? |
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 _____. |
red algae |
Green algae differ from land plants in that many green algae _____. |
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) |
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 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? |
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 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? |
loss of chloroplasts |
Which of the following organisms is a producer? |
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." |
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? |
reduced populations of producers because they have access to fewer nutrients |
Plastids that are surrounded by more than two membranes are evidence of |
secondary endosymbiosis. |
Biologists suspect that endosymbiosis gave rise to mitochondria before plastids partly because |
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? |
Mitochondria |
Which of the following statements supports the hypothesis of an endosymbiotic origin of mitochondria? |
Each mitochondrion has its own DNA molecule. |
Proteins consist of amino acids linked to fatty acids. |
Other amino acids |
Which of the following is hydrophobic and therefore insoluble in water? phospholipid |
lipid |
Animals obtain the energy they need for growth by using ATP in food. |
breaking down organic molecules. |
The mammalian trachea and esophagus both connect to the large intestine. |
pharynx |
Which of the following organs is incorrectly paired with its function? |
large intestine-bile production |
Which of the following is not a major activity of the stomach? |
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? Digestion doesn’t begin until the small intestine. |
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. |
Identify the roles played by human gut bacteria. |
Ulcers are caused by the acid-tolerant bacterium Helicobacter pylori. |
Bacteria in the human gut are which of the following? |
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. |
If you put the following events in the order they occur in the human digestive system, the third event in the series would be: |
Pepsin activates pepsinogen. |
Mastering Biology Review #3
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