Which of the following statements about the properties of life is false? |
Organisms have an unchanging, constant internal environment |
Life is organized in a hierarchical fashion. Which of the following sequences correctly lists that hierarchy from least inclusive to most inclusive? |
molecule, organelle, cell, tissue, organ, organ system, organism, population, community, ecosystem |
Which of the following statements regarding a common cellular activity is false? |
New cells are derived from cellular components like organelles. |
Your instructor asks you to look into your microscope to see a prokaryotic cell. You will be looking for a cell that |
has a membrane. |
In an ecosystem, energy |
typically flows from producers through a series of consumers. |
Organisms that are prokaryotes are in the domains |
Bacteria and Archaea |
Kindom Fungi includes species |
that obtain food by decomposing dead organisms and absorbing the nutrients. |
Organisms belonging to the kingdom Plantae |
are photosynthetic. |
Which of the following statements about evolution is true? |
evolution can result in adaptations. |
A hypothesis is |
a proposed explanation for a set of observations. |
A theory is |
an explanation of an idea that is broad in scope and supported by a large body of evidence. |
Organisms that are prokaryotes are in domains |
Bacteria and Archaea |
Which of the following statements about genetics is true? |
Differences among organisms reflect different nucleotide sequences in their DNA. |
In an ecosystem, energy |
typically flows from producers through a series of consumers. |
Which of the following statements regarding a common cellular activity is false? |
New cells are derived from cellular components like organelles. |
The tree in your backyard is home to two cardinals, a colony of ants, a wasp's nest, two squirrels, and millions of bacteria. Together, all of these organisms represent |
a community. |
Which of the following statements about the domain Bacteria is true? |
All bacteria lack a nucleus. |
Kingdom Fungi includes species |
that obtain food by decomposing dead organisms and absorbing the nutrients. |
Which of the following statements is not consistent with Darwin's theory of natural selection? |
Individual organisms experience genetic change during their life spans to better fit their environment. |
Organisms belonging to the kingdom Plantae |
are photosynthetic. |
Consider the following statement: "If all vertebrates have backbones, and turtles are vertebrates, then turtles have backbones." This statement is an example of |
deductive reasoning. |
A hypothesis is |
a proposed explanation for a set of observations. |
A theory is |
an explanation of an idea that is broad in scope and supported by a large body of evidence. |
The role of a control in an experiment is to |
provide a basis of comparison to the experimental group. |
A scientist performs a controlled experiment. This means that |
two versions of the experiment are conducted, one differing from the other by only a single variable. |
Which of the following statements about ecosystems is false? |
Energy cycles from organisms through the atmosphere back to the organisms. |
Which of the following statements provides the best evidence that there is a common genetic code that demonstrates the unity of life? |
Through genetic engineering, a gene from a firefly can be inserted into a bacterium to make it glow. |
Which of the following organisms is represented in box 1? |
Tree |
The box numbered 2 represents which of the following? |
the cycling of matter |
The four most common elements in living organisms are |
C, H, O, N. |
Which of the following is a trace element in the human body? |
Zinc |
Which of the following statements best describes a compound? |
A compound contains two or more different elements in a fixed ratio. |
In the equation 2 H₂ +O₂ → 2H₂O, |
only H₂O is a compound. |
Which of the following trace elements needed by humans is commonly added to table salt? |
iodine |
In some areas, fluoride is added during the municipal water treatment process in order to |
reduce tooth decay. |
Which of the following particles are found in the nucleus of an atom? |
only protons and neutrons. |
What is the atomic mass of an atom that has 6 protons, 6 neutrons, and 6 electrons? |
12 |
An uncharged atom of boron has an atomic number of 5 and an atomic mass of 11. How many electrons does boron have? |
5 |
The sodium atom contains 11 electrons, 11 protons, and 12 neutrons. What is the mass number of sodium? |
23 |
Which of the following best describes the atomic number of an atom? |
the number of protons in the atom |
Typically, nitrogen atoms are composed of electrons, protons, and neutrons. An isotope of nitrogen could |
have more neutrons than the usual nitrogen atom. |
A radioactive isotope is an isotope that |
decays. |
Which of the following statements about radioactive isotopes is true? |
The energy emitted by radioactive isotopes can break chemical bonds and cause molecular damage to the cells. |
Radioactive isotopes |
can be used in conjunction with PET scans to diagnose diseases. |
What happens to an atom if the electrons in the outer shell are altered? |
The properties of the atom change. |
A/an _________ bond forms when two atoms share electrons. |
covalent bond |
Table salt is formed when |
sodium donates its single outer electron to chlorine. |
Which of the following statements regarding the oxygen atom of the water molecule is true? |
Oxygen is more electronegative than the hydrogen atoms. |
In a water molecule, hydrogen and oxygen are held together by a ____________ bond. |
polar covalent |
Water molecules stick to other water molecules because |
hydrogen bonds form between the hydrogen atoms of one water molecule and the oxygen atoms of other water molecules. |
In the equation 2 H₂ + O₂ → 2 H₂O, the H₂ molecules are ________ and the H₂O molecules are __________. |
reactants, products |
The tendency of water molecules to stick together is referred to as |
cohesion. |
Water's surface tension and heat storage capacity are accounted for by its |
hydrogen bonds. |
In plants, the process of photosynthesis produces glucose (C₆H₁₂O₆) and oxygen from carbon dioxide and water. Which of the following statements about photosynthesis is true? |
All of the carbon atoms from the carbon dioxide are found in glucose. |
Lactose intolerance is the inability to |
digest lactose. |
Organic compounds |
always contain carbon. |
Which of the following statements regarding carbon is false? |
Carbon has the ability to bond with up to six other atoms. |
Which of the following statements about hydrocarbons is false? |
Hydrocarbons are inorganic compounds. |
Propanol and isopropanol are isomers. This means that they have |
the same molecular formula but different chemical properties. |
A hydroxyl group is |
characteristic of alcohols. |
Which of the following is a carboxyl group? |
-COOH |
Which of the following is an amino group? |
-NH₂ |
Which of the following contains a carboxyl group and an amino group? |
amino acid |
Which of the following functional groups is capable of regulating gene expression? |
-CH₃ |
Which of the following statements about dehydration synthesis is false? |
Animal digestive systems utilize this process to break down food. |
The results of dehydration synthesis can be reversed by |
hydrolysis. |
What is the general function of enzymes within a cell? |
to speed up chemical reactions |
The molecular formula of most monosaccharides represents a multiple of |
CH₂O. |
Many names for sugars end in the suffix |
-ose. |
A disaccharide forms when |
two monosaccharides join by dehydration synthesis. |
Which of the following lists contains only polysaccharides? |
cellulose, starch, and glycogen |
Cellulose differs from starch in that |
most animals cannot break down cellulose, whereas starch is easily digested. |
Cows can derive nutrients from cellulose because |
their intestinal tract contains cellulose-hydrolyzing microorganisms. |
Which of the following organisms contain the polysaccharide chitin? |
fungi and plants |
The storage form of carbohydrates is _______ in animals and ________ in plants. |
glycogen; starch |
An oil may be converted into a substance that is solid at room temperature by |
adding hydrogens, decreasing the number of doubles bonds in the molecules. |
What feature of fats makes them hydrophobic? |
Fats have nonpolar hydrocarbon chains. |
Which of the following statements regarding triglyceride molecules is false? |
Triglycerides are hydrophilic. |
Fatty acids with double bonds between some of their carbons are said to be |
unsaturated. |
The development of atherosclerotic disease can result from a diet high in |
saturated fats. |
Which of the following statements about animal cell lipids is false? |
Many lipids function as enzymes. |
A phospholipid is composed of |
one glycerol molecule linked to one phosphate group and two fatty acids. |
Amino acids can be distinguished from one another by |
the chemical properties of their R groups. |
Peptide bonds |
link amino acids. |
Which of the following would be correctly classified as a protein? |
an enzyme |
Structural proteins |
are found in hair and tendons. |
Proteins cannot be denatured by |
freezing. |
Which of the following characteristics of protein will remain intact if the protein is denatured? |
the number of amino acids in the protein. |
The primary structure of a protein is |
the amino acid sequence of the polypeptide chain. |
Which of the following is an example of secondary structure in a protein? |
an alpha helix |
The tertiary structure of a polypeptide refers to |
the overall three-dimensional structure. |
A protein containing more that one polypeptide chain exhibits the ______ level of protein structure. |
quaternary |
How are genes used by cells to build proteins? |
The genes in DNA direct the synthesis of an RNA molecule, which is used to build a protein. |
DNA differs from RNA because DNA |
contains thymine place of uracil. |
Because carbon atoms have four electrons in their outermost energy level, they can form ____ covalent bonds with other atoms. |
four |
In a condensation or dehydration reaction, two molecules become linked together and a molecule of ____ is produced. |
H₂O |
Lipids are __________ molecules because they have no negative and positive poles. |
non-polar |
A substrate attaches to the ________ of an enzyme. |
active site |
ATP contains _______ phosphate groups. |
three |
Light microscopes |
use light and glass lenses to magnify an image. |
One centimeter = ________ millimeters. |
10 |
Resolution is the |
the ability of an optical instrument to show two close objects as separate. |
Which of the following statements about electron microscopes is true? |
transmission electron microscopes are mainly used to study cell surfaces. |
Which step of the citric acid cycle requires both NAD+ and ADP as reactants? |
step 3 |
Which H+ has just passed through the inner mitochondrial membrane by diffusion? |
hydrogen ion D |
If ATP accumulates in a cell, |
feedback inhibition slows down cellular respiration. |
The conversion of CO₂ and H₂O into organic compounds using energy from light is called |
photosynthesis. |
If you consume 1 g of each of the following, which will yield the most ATP? |
fat |
When a cell uses fatty acids for aerobic respiration, it first hydrolyzes fats to |
glycerol and fatty acids. |
Yeasts can produce ATP by either fermentation or oxidative phosphorylation; thus, they are |
facultative anaerobes. |
Bacteria that are unable to survive in the presence of oxygen are called |
obligate anaerobes. |
In yeast cells, |
alcohol is produced after glycolysis. |
In fermentation, ________ is _________. |
NADH; oxidized |
Which of the following processes produces the most ATP per molecule of glucose oxidized? |
aerobic respiration |
The energy yield from the breakdown of a single molecule of glucose does not depend upon |
the supply of carbon dioxide. |
Which of the following statements about the energy yield of aerobic respiration is false? |
Oxidative phosphorylation resulting from 1 glucose molecule yields about 12 ATP molecules. |
In the electron transport chain, the final electron acceptor is |
an oxygen atom. |
By-products of cellular respiration include |
carbon dioxide and water. |
During chemiosmosis, |
ATP is synthesized when H+ ions move through a channel in ATP synthase. |
At the end of the citric acid cycle, most of the energy remaining from the original glucose is stored in |
NADH. |
The function of coenzyme A in the citric acid cycle is most like |
a limousine driver dropping off a couple at the school prom. |
The end products of the citric acid cycle include all of the following except |
a pyruvate. |
After glycolysis but before the citric acid cycle, |
pyruvate is oxidized. |
Pyruvate |
forms at the end of glycolysis. |
The end products of glycolysis include |
NADH. |
Which of the following is a result of glycolysis? |
conversion of glucose to two three-carbon compounds |
How many molecules of NADH are produced during glycolysis? |
2 |
As a result of glycolysis, there is a net gain of _____ ATP(s). |
2 |
During which of the following phases of cellular respiration does substrate-level phosphorylation take place? |
glycolysis and the citric acid cycle |
Which of the following options lists the stages of cellular respiration in the correct order? |
glycolysis, the citric acids cycle, and oxidative phosphorylation |
The functioning of an electron transport chain is analogous to |
a Slinky toy going down a flight of stairs. |
During cellular respiration, NADH |
delivers its electron load to the first electron carrier molecule. |
In biological systems, an important enzyme involved in the regulation of redox reactions is |
dehydrogenase. |
Oxidation is the _________, and reduction is the ________. |
loss of electrons; gain of electrons |
During cellular respiration, the energy in glucose |
is carried by electrons. |
A kilocalorie is defined as |
the quantity of heat needed to raise the temperature of 1 kg of water by 1°C. |
Humans use about ________ of their daily calories to maintain brain cells and power other life-sustaining activities. |
75% |
Humans use the calories they obtain from ________ as their source of energy. |
food |
Which of the following statements about the energy yields from cellular respiration is true? |
Cellular respiration is more efficient at harnessing energy from glucose than car engines are at harnessing energy from gasoline. |
The overall equation for the cellular respiration of glucose is |
C₆H₁₂0₆ + 6O₂ → 6CO₂ + 6H₂O + energy. |
Which of the following are products of cellular respiration? |
energy to make ATP and carbon dioxide |
Respiration ____________, and cellular respiration __________. |
is a gas exchange; produces ATP |
The processes of photosynthesis and cellular respiration are complementary. During these energy conversions, some energy is |
lost in the form of heat. |
Which of the following statements regarding photosynthesis and cellular respiration is true? |
Photosynthesis occurs in chloroplasts, and cellular respiration occurs in mitochondria. |
How do cells capture energy released by cellular respiration? |
They produce ATP. |
Which of the following statements regarding the movement of electrons during cellular respiration is true? |
O₂ is reduced when it accepts electrons and forms water. |
Which of the following metabolic pathways is common in aerobic and anaerobic metabolism? |
glycolysis |
The mitochondrial cristae are an adaptation that |
increases the space for more copies of the electron transport chain and ATP synthase complexes. |
To obtain energy from starch and glycogen, the body must begin by |
hydrolyzing both starch and glycogen to glucose. |
NADH pills can be purchased over the counter and are often taken by sufferers of chronic fatigue syndrome (CFS). How might these pills benefit a CFS patient? |
They would increase the number of electrons provided to the electron transport chain. |
The Krebs cycle takes place in the ________. |
mitochondria |
In the absence of oxygen, glycolysis is followed by ________ instead of aerobic respiration. |
anaerobic |
Glucose is split into smaller molecules (pyruvate) during a biochemical pathway called ________. |
glycolysis |
The idea that all living things are composed of cells and that all cells come from other cells defines |
cell theory. |
A scanning electron microscope is used to study ________, whereas a transmission electron microscope is used to study ________. |
cell surfaces; internal cell structures |
As cell size increases, the |
volume increases proportionally more than the surface area. |
In the plasma membrane, the phospholipid heads |
are hydrophilic and face outward toward the aqueous solution on both sides of the membrane. |
Archaea are composed of _______ cells. |
prokaryotic |
The nucleoid region of prokaryotic cell |
contains the cell's DNA. |
Which of the following structures is/are used by prokaryotes for attaching to surfaces? |
capsule |
You are told that the cells on a microscope slide are plant, animal, or bacterial. You look at the them through a microscope and see cell walls and membrane-bound organelles. You conclude correctly that the cells |
are plant cells. |
Unlike animal cells, plant cells have _____ and _______. Unlike plant cells, animal cells have ________. |
chloroplasts; cell walls; centrioles |
The nucleus of a cell |
contains DNA. |
During cell reproduction, chromatin fibers coil up into structures called |
chromosomes. |
The function of the nucleolus is |
to manufacture ribosomal RNA. |
Smooth endoplasmic reticulum |
stores calcium ions in muscle cells. |
The main function of the rough endoplasmic reticulum is the production of |
membrane and proteins secreted by the cell. |
The cells that produce hair made of protein contain a lot of _________, while the cells that produce the oils that coat the hair contain a lot of ________. |
rough endoplasmic reticulum; smooth endoplasmic reticulum |
The Golgi apparatus |
stores, modifies, and packages proteins. |
Which of the following statements about lysosomes is false? |
Lysosomes synthesize proteins from the recycled amino acids. |
Which of the following statements regarding the Golgi apparatus is false? |
The Golgi apparatus decreases in size when a cell increases its protein production. |
The oil from the sebaceous glands is produced by which of the following cell organelles? |
smooth endoplasmic reticulum |
The graph shows that |
not all cells at any given stage have the same amount of protein. |
The endomembrane system includes all of the following organelles except the |
peroxisome. |
Water's surface tension and heat storage capacity are accounted for by its |
hydrogen bonds. |
As ice melts, |
hydrogen bonds are broken. |
Which of the following statements about water is false? |
Ice is more dense than liquid water. |
You've made a hot drink by dissolving a teaspoon of instant coffee and a teaspoon of sugar in a cup of hot water. Which of the following statements is true? |
You've just prepared an aqueous solution. |
Which of the following is dependent on the ability of water molecules to form hydrogen bonds with other molecules besides water? |
the universality of water as a solvent |
A pharmaceutical company hires a chemist to analyze the purity of the water being used in its drug preparations. If the water is pure, the chemist would expect to find |
H₂O molecules, H+ ions, and OH- ions. |
A solution with a pH of 7 is |
neutral |
Compared to solution of pH 3, a solution of pH 1 is |
100 times more acidic. |
Which of the following statements about pH is true? |
An increase in hydrogen ion concentration means a decrease in pH scale units. |
Household ammonia has a pH of 12; household bleach has a pH of 13. Which of the following statements about these substances is true? |
The ammonia has 10 times as many H+ ions as the bleach. |
A buffer |
donates H+ ions when conditions become too basic and accepts H+ ions when conditions become too acidic. |
Which of the following statements about cells is true? |
All cells have internal structures that move. |
Light microscopes |
use light and glass lenses to magnify an image. |
Resolution is the |
ability of an optical instrument to show two close objects as separate. |
Which of the following statements about electron microscopes is true? |
Electron microscopes focus electron beams to create a magnified image of an object. |
The idea that all living things are composed of cells and that all cells come from other cells defines |
cell theory. |
A scanning electron microscope is used to study _________, whereas a transmission electron microscope is used to study __________. |
cell surfaces; internal cell structures |
A cell is exposed to a substance that prevents it from dividing. The cell becomes larger and larger. This situation |
will eventually be problematic, since the cell's ability to absorb nutrients through its outer membrane will not keep increasing as quickly as its cytoplasmic needs. |
In the plasma membrane, the phospholipid heads |
are hydrophilic and face outward toward the aqueous solution on both sides of the membrane. |
Which of the following structures is exclusively associated with prokaryotic cells? |
nucleoid |
________ cells lack a membrane-enclosed nucleus. |
prokaryotic |
Which of the following structures is/are used by prokaryotes for attaching to surfaces? |
capsule |
Unlike animal cells, plant cells have _______ and _______. Unlike plant cells, animal cells have _________. |
chloroplasts; cell walls; centrioles |
The nucleus of a cell |
contains DNA. |
During cell reproduction, chromatin fibers coil up into structures called |
chromosomes. |
The function of the nucleolus is |
to manufacture ribosomal RNA. |
The endomembrane system includes all of the following organelles except the |
peroxisome. |
Smooth endoplasmic reticulum |
stores calcium ions in muscle cells. |
The main function of the rough endoplasmic reticulum is the production of |
membrane proteins secreted by the cell. |
Secretory proteins are |
released from the cell through the plasma membrane. |
The Golgi apparatus |
stores, modifies, and packages proteins. |
The cells that produce hair made of protein contain a lot of _________, while the cells that produce the oils that coat the hair contain a lot of ________. |
rough endoplasmic reticulum; smooth endoplasmic reticulum |
Which of the following statements regarding the Golgi apparatus is false? |
The Golgi apparatus decreases in size when a cell increases its protein production. |
Which of the following statements about lysosomes is false? |
Lysosomes synthesize proteins from the recycled amino acids. |
Tay-Sachs disease |
causes an accumulation of lipids in brain cells. |
Which of the following statements about the function of a plant cell central vacuole is false? |
The central vacuole of a plant cell may store poisons. |
Contractile vacuoles |
prevent cells from bursting as a result of the influx of excess salt water. |
Which organelle is involved in the catabolism of fatty acids and the detoxification of alcohol? |
peroxisome |
Insulin is a protein that is produced by pancreatic acids and secreted into the bloodstream. Which of the following options correctly lists the order of the structures through which insulin passes from its production to its exit from the cell. |
rough ER, transport vesicles, Golgi apparatus, transport vesicles, cell membrane |
The function of mitochondria is |
cellular respiration. |
The _________ of a mitochondrion is/are an adaptation that increases the surface area and enhances a mitochondrion's ability to produce ATP. |
cristae |
The function of chloroplasts is |
photosynthesis. |
The stroma is |
the thick fluid enclosed by the inner chloroplast membrane. |
Mitochondria differ from chloroplasts in that mitochondria |
contain membrane folds called cristae, whereas chloroplasts contain disk-like vesicles in stacks called grana. |
The endosymbiosis hypothesis proposes that |
a small cell lived inside a larger cell to the benefit of both cells. |
Microfilaments differ from microtubules in that microfilaments |
are mainly composed of actin, whereas microtubules are composed of tubulin. |
Intermediate filaments |
surround the nucleus. |
Cilia differ from flagella in that |
cilia are typically more numerous and shorter that flagella. |
Dynein feet |
are found on microtubules in cilia and flagella and cause movement by grabbing and pulling at adjacent microtubule doublets. |
The extracellular matrix attached to the cells via glycoproteins may then bind to _________ in the plasma membrane. |
integrins |
It is essential for heart muscle cells to beat in a coordinated fashion. The cell junctions that would best facilitate this are |
gap junctions |
Skin cells are fastened into strong sheets by |
anchoring junctions. |
Which of the following statements regarding plasmodesmata is false? |
Plasmodesmata are found in plants as well as some single-celled organisms. |
Which part of the mitochondrion shown enhances its ability to produce ATP by increasing the surface area of a mitochondrial membrane? |
structure D (cristae) |
Based on their function, you would expect melanocytes in the skin to have a higher that usual number of |
ribosomes. |
The oil from the sebaceous glands is produced by which of the following cell organelles? |
smooth endoplasmic reticulum |
The fluid mosaic model describes the plasma membrane as consisting of |
diverse proteins embedded in a phospholipid bilayer. |
Membrane phospholipids |
are able to drift about in the plasma membrane. |
Most of the functions of a cell membrane, including transport and enzymatic function, are performed by |
proteins |
Which of the following statements regarding membrane protein function is false? |
Membrane proteins transfer genetic information to the cytoplasm. |
Relaying a message from a membrane receptor to a molecule that performs a specific function within a cell occurs when |
a signaling molecule binds to a protein that extends to the outside of the cell. |
Plasma membranes are selectively permeable. This means that |
the plasma membrane allows some substances to enter or leave a cell more easily than others. |
Which of the following statements regarding membrane function is false? |
The plasma membrane is the control center of the cell. |
All cells are enclosed by a plasma membrane that is similar in _______ and _______. |
structure; function |
Small, nonpolar, hydrophobic molecules such as fatty acids |
easily pass through a membrane's lipid bilayer. |
Which of the following substances would have the most trouble crossing a biological membrane by diffusing through the lipid bilayer? |
Na+ |
Oxygen crosses a plasma membrane by |
passive transport. |
Which of the following statements regarding diffusion is false? |
Diffusion occurs when particles spread from area where they are less concentrated to areas where they are more concentrated. |
Osmosis can be defined as |
the diffusion of water. |
Some protozoans have special organelles called contractile vacuoles that continually eliminate excess water from the cell. The presence of these organelles telles you that the environment |
is hypotonic to the protozoan. |
A cell that has neither a net gain of water nor a net loss of water when it is immersed in a solution must be |
isotonic to its environment. |
In a hypotonic solution, an animal cell will |
lyse. |
If placed in tap water, an animal cell will undergo lysis, whereas a plant cell will not. What accounts for this difference? |
the relative inelasticity and strength of the plant cell wall |
In the lab, you use a special balloon that is permeable to water but not sucrose to make an "artificial cell." The balloon filled with a solution of 20% sucrose and 80% water and is immersed in a beaker containing a solution of 40% sucrose and 60% water. The solution in the balloon is _____ relative to the solution in the beaker. |
hypotonic |
A plant cell in a hypotonic solution |
becomes turgid because of an inflow of water. |
Facilitated diffusion across a biological membrane requires _________ and moves a substance _________ its concentration gradient. |
transport proteins; down |
The molecules responsible for membrane transport are |
proteins |
Aquaporins |
allow water to cross the plasma membrane via facilitated diffusion. |
Which of the following is a typical feature of an ATP-driven active transport mechanism? |
The solute moves against the concentration gradient. |
Certain cells that line the stomach synthesize a digestive enzyme and secrete it into the stomach. This enzyme is a protein. Which of the following processes could be responsible for its secretion? |
exocytosis |
The process of a white blood cell engulfing a bacterium |
phagocytosis |
Phagocytosis is to eating as pinocytosis is to |
drinking. |
Cells acquire low-density lipoproteins (LDLs) by |
receptor-mediated endocytosis. |
Kinetic energy differs from chemical energy in that |
kinetic energy is the energy of a moving object, whereas chemical energy is the potential energy of molecules. |
In the reaction A → B + C + heat, |
the potential energy of the products is less than that of the reactant. |
According to ________, energy cannot be created or destroyed. |
the first law of thermodynamics |
Which of the following processes is endergonic? |
the synthesis of glucose from carbon dioxide and water |
When a cell uses chemical energy to perform work, it uses the energy released from a/an ______ reaction to drive a/an ______ reaction. |
exergonic; endergonic |
The transfer of a phosphate group to a molecule or compound is called |
phosphorylation. |
The energy required to initiate an exergonic reaction is called |
activation energy. |
Most of a cell's enzymes are |
proteins. |
The active site of an enzyme is |
the region of an enzyme that attaches to a substrate. |
Which of the following statements regarding enzyme function is false? |
Enzymes are used up when they catalyzes a chemical reaction so must be synthesized for each new chemical reaction. |
Heating inactivates enzymes by |
changing the enzyme's three-dimensional shape. |
How does inhibition of an enzyme-catalyzed reaction by a competitive inhibitor differ from inhibition by a noncompetitive inhibitor? |
Competitive inhibitors bind to the active site of the enzyme, noncompetitive inhibitors bind to a different site. |
Which of the following is a coenzyme? |
vitamin B₆ |
You are adrift in the Atlantic ocean and, being thirsty, drink the surrounding seawater. As a result, |
you dehydrate yourself. |
Which of the following statements regarding thermodynamics is false? |
An automobile engine is a closed system because it does not exchange energy and matter with its surroundings. |
Which of the following substances could be a cofactor? |
a zinc atom |
Which of the following processes is a classifed as a metabolic pathway? |
protein synthesis |
Bacterial production of the enzymes needed for the synthesis of the amino acid tryptophan declines with increasing levels of tryptophan and increases as tryptophan levels decline. This is an example of |
feedback inhibition |
What is the name given to organisms that can make their own food and thus sustain themselves without consuming organic molecules derived from other organisms? |
autotrophs |
Autotrophs that utilize light as their energy source are |
photoautotrophs. |
CO₂ enters and O₂ escapes from a leaf via |
stomata. |
In the chloroplast, sugars are made in a compartment that is filled with a thick fluid called the |
stroma. |
Thylakoids are arranged in stacks called |
grana. |
The oxygen released into the air as a product of photosynthesis comes from |
water. |
Which of the following molecules is a reactant of photosynthesis? |
CO₂ |
What is the source of energy that provides the boost for electrons during photosynthesis? |
light |
The light reactions occur in the ______, while the Calvin cycle occurs in the ________. |
thylakoid membranes; stroma |
Which of the following are produced during the light reactions of photosynthesis? |
ATP, NADPH, O₂ |
Which of the following are produced during the Calvin cycle? |
glucose, ADP, NADP+ |
Sunlight is a type of ______ energy. |
electromagnetic |
The full range of electromagnetic energy is called the _______ spectrum. |
electromagnetic |
Carbon fixation |
occurs when the carbon atoms from CO₂ are incorporated into an organic molecule. |
Why are most plants green? |
Chlorophyll a reflects green light. |
Chlorophyll b |
passes absorbed energy to chlorophyll a. |
Which of the following wavelengths of light would you expect to be reflected or transmitted by chlorophyll a? |
green |
A packet of light energy is called a |
photon. |
Which of the following photosynthetic pigments can be found at the photosystem reaction center? |
chlorophyll a |
Which of the following molecules is a product of photosynthesis? |
glucose and O₂ |
In a photosystem, clusters of chlorophyll a, chlorophyll b, and carotenoid pigments function most like |
an antenna. |
As a result of the cascade of electrons down the electron transport chains of the light reactions, |
NADP+ is reduced to NADPH. |
Photosystem II |
passes electrons to photosystem I. |
In this drawing of a chloroplast, which structure represents the thylakoid membrane? |
structure C |
According to this figure, how do hydrogen ions make their way from the stroma to the thylakoid interior? |
through an electron transport chain molecule |
If you focus on the data from the mid-1900s (indicated by the arrow) through today, the graph shows that |
there is a correlation between CO₂ and temperature, when CO₂ levels are high, so is temperature. |
Autotrophs that utilize light as their energy source are |
photoautotrophs. |
What is the name given to organisms that can make their own food and thus sustain themselves without consuming organic molecules derived from other organisms? |
autotrophs |
CO₂ enters and O₂ escapes from a leaf via |
stomata. |
Thylakoids are arranged in stacks called |
grana. |
The oxygen released into the air as a product of photosynthesis comes from |
water. |
Which of the following molecules is a reactant of photosynthesis? |
CO₂ |
A redox reaction involves the transfer of |
an electron. |
What is the source of energy that provides the boost for electrons during photosynthesis? |
light |
The light reactions occur in the ______, while the Calvin cycle occurs in the ________. |
thylakoid membranes; stroma |
Which of the following are produced during the Calvin cycle? |
glucose, ADP, NADP+ |
The full range of electromagnetic energy is called the _______ spectrum. |
electromagnetic |
What are most plants green? |
Chlorophyll a reflects green light. |
Chlorophyll b |
passes absorbed energy to chlorophyll a. |
A packet of light energy is called a |
photon. |
Which of the following photosynthetic pigments can be found at the photosystem reaction center? |
chlorophyll a |
Which of the following molecules is a product of photosynthesis? |
glucose and O₂ |
Clusters of light-gathering pigments in a photosystem |
pass energy to the reaction center. |
In a photosystem, clusters of chlorophyll a, chlorophyll b, and carotenoid pigments function most like |
an antenna. |
The electron transport chains of the light reactions |
shuttle electrons from photosystem II to photosystem I. |
As a result of the cascade of electrons down the electron transport chains of the light reactions, |
NADP+ is reduced to NADPH. |
Photosystem II |
passes electrons to photosystem I. |
In photophosphorylation, energy from electron flow is used to transport _______ from the _______ to the thylakoid compartment, generating a concentration gradient of _________. |
H+, stoma, H+ |
In chloroplasts, ATP synthase |
phosphorylates ADP to ATP. |
Mitochondria transfer _______ energy from ________ to ATP; chloroplasts transform _________ energy into the chemical energy of ATP. |
chemical; food; light |
The addition of oxygen instead of carbon dioxide to RuBP results in |
photorespiration. |
What is the main adaptive advantage of the C₄ and CAM photosynthesis strategies over the C₃ strategy? |
They help the plant synthesize glucose efficiently under dry conditions. |
Many of the regions of the world where hunger is prevalent are also regions with hot and dry climates. What types of agricultural crops would you suggest that these regions attempt to grow? |
C₄ and CAM plants |
Put the following steps of the light reactions in the correct order: |
2, 4, 1, 3 |
Put the following steps of the Calvin cycle in the correct order: |
1, 4, 3, 2 |
________ cells in leaves are specialized for photosynthesis. |
Mesophyll |
Which of the following statements comparing photosynthesis and cellular respiration is false? |
ATP is not produced during photosynthesis; it is produced only during cellular respiration. |
Plant cells are protected from the harmful effects of excessive light energy and reactive oxidative molecules by |
carotenoids. |