biology test 3 quiz questions

While reading an online resource, a student noticed an error in the paragraph below: In photosynthesis, ATP is generated in the light reactions and used in the light-independent reactions as a reducing agent to reduce carbon dioxide to form carbohydrates, which the plant can use for structure and energy. Which word or phrase could be changed to eliminate the error? A. ATP B. Light-independent reactions C. Reducing agent D. Carbon dioxide E. Structure

A. ATP

Refer to the graph below. (http://www.macmillanhighered.com/brainhoney/Resource/6274028,8,0,0,0/Assets/resources/ch08_summative_quiz/q10-1.png) The letter _______ labels the transition state, and the free energy change for this reaction has a _______ value. A. B; negative B. C; positive C. D; negative D. B; positive E. C; negative

B. C; positive

2. Which reaction is not an oxidation-reduction reaction? A. NADH + ½ O2 + H+ → NAD+ + H2O B. R — CH = CH — CH3 + H2O → RCH2 — CH (OH) — CH3 C. FAD + H2O → FADH2 + ½ O2 D. NADH + acetaldehyde → NAD+ + ethanol E. AH2 + B → A + BH2

B. R — CH = CH — CH3 + H2O → RCH2 — CH (OH) — CH3

Refer to the table. Run number NADH FADH2 O2 ADP Pi 1 ✔ ✔ ✔ ✔ 2 ✔ ✔ ✔ ✔ 3 ✔ ✔ ✔ ✔ 4 ✔ ✔ ✔ ✔ A student runs the simulation multiple times, each time leaving out a different molecule. Which run or runs would result in ATP production? A. Only run 1 B. Runs 1 and 3 C. Runs 3 and 4 D. Runs 1 and 2

B. Runs 1 and 3

Which parameter is indicative of how far and in what direction a reaction will progress? A. The concentration of reactants B. The change in free energy of the reaction (ΔG) C. The concentration of products D. The change in enthalpy of the reaction (ΔH) E. The overall size of the system in which the reaction occurs

B. The change in free energy of the reaction (ΔG)

The synthesis of complex molecules is _______, whereas their degradation is _______. Synthesis occurs with _______ in entropy. A. endergonic; exergonic; an increase B. endergonic; exergonic; a decrease C. exergonic; endergonic; no change D. exergonic; endergonic; an increase E. endergonic; exergonic; no change

B. endergonic; exergonic; a decrease

C4 plants differ from C3 plants because C3 plants _______, while C4 plants _______. A. produce a four-carbon intermediate after CO2 fixation; produce a three-carbon intermediate after CO2 fixation B. have mesophyll cells that fix CO2 and contain the Calvin cycle; have mesophyll cells that fix CO2 and bundle sheath cells that contain the Calvin cycle C. gain CO2 via photorespiration; lose CO2 via photorespiration D. can concentrate the CO2 by regulating the stomata closure; can concentrate CO2 at night E. concentrate CO2 near rubisco; cannot concentrate CO2 near rubisco

B. have mesophyll cells that fix CO2 and contain the Calvin cycle; have mesophyll cells that fix CO2 and bundle sheath cells that contain the Calvin cycle

13. Reagents, such as dinitrophenol, increase the permeability of the mitochondrial inner membrane to protons. The addition of dinitrophenol to a suspension of animal cells should A. decrease the rate of oxidation of NADH. B. inhibit mitochondrial ATP synthesis. C. increase lactic acid production. D. decrease the rate of pyruvate oxidation. E. stimulate ATP synthesis by mitochondria.

B. inhibit mitochondrial ATP synthesis.

3. The conversion of malate to oxaloacetate in the citric acid cycle takes place with the conversion of NAD+ to NADH. In this reaction, NAD+ is a(n) A. reducing agent. B. oxidizing agent. C. allosteric inhibitor. D. allosteric activator. E. feedback inhibitor.

B. oxidizing agent.

8. Which compounds link glycolysis and the citric acid cycle to the electron transport chain? A. NADH and ATP B. ADP and Pi C. FADH2 and NADH D. ATP and CO2 E. Pyruvate and acetyl CoA

C. FADH2 and NADH

According to the chemiosmotic mechanism, what is the direct source of the energy used to synthesize ATP from ADP in chloroplasts and in mitochondria? A. Glucose B. Water C. Proton gradient D. Electrons

C. Proton gradient

Which statement about ATP is false? A. The synthesis of ATP is an endergonic reaction. B. The hydrolysis of ATP to ADP and Pi is an exergonic reaction. C. The phosphate bond energy of ATP cannot be harnessed for work. D. ATP is a building block of RNA. E. The phosphate bond energy of ATP may be transformed into light energy.

C. The phosphate bond energy of ATP cannot be harnessed for work.

11. The synthesis of ATP from ADP and Pi is an _______ reaction. In mitochondria, ATP synthesis is driven by the flow of _______ down a concentration gradient established by _______. A. endergonic; Na+ ions; electron transport B. exergonic; protons; glycolysis C. endergonic; protons; electron transport D. exergonic; Na+ ions; glycolysis E. endergonic; protons; the citric acid cycle

C. endergonic; protons; electron transport

4. The end products of glycolysis are A. pyruvate, ATP, and CO2. B. pyruvate, ATP, and NAD+. C. pyruvate, ATP, and NADH. D. acetyl CoA, ATP, and NAD+. E. acetyl CoA, ATP, and NADH.

C. pyruvate, ATP, and NADH.

Plants that carry out crassulacean acid metabolism (CAM) differ from C4 plants in that A. they do not contain PEP carboxylase. B. they do not carry out the Calvin cycle. C. their stomata are open at night. D. they do not need ATP for photosynthesis. E. they do not contain rubisco.

C. their stomata are open at night.

Refer to the table below. Solution PH A . 9 B . 3 C . 8 Which two solutions can be paired across a membrane to create the greatest potential energy gradient, and in which direction will the flow of protons release this energy? A. A → B B. B → C C. C → A D. B → A

D. B → A

Which statement about chlorophyll is false? A. Chlorophyll appears green because it reflects green light. B. Most of the chlorophyll in a plant functions to gather light. C. Chlorophyll is present in light-harvesting complexes also known as antenna systems. D. Most of the chlorophyll in a plant participates in an oxidation-reduction reaction. E. Chlorophyll contains Mg2+.

D. Most of the chlorophyll in a plant participates in an oxidation-reduction reaction.

Refer to the table. Run number NADH FADH2 O2 ADP Pi 1 ✔ ✔ ✔ ✔ 2 ✔ ✔ ✔ ✔ 3 ✔ ✔ ✔ ✔ 4 ✔ ✔ ✔ ✔ A student runs the simulation multiple times, leaving out different molecules to test the effects. Which run or runs would produce water but no ATP? A. Only run 4 B. Runs 1 and 3 C. Runs 1 and 2 D. Runs 2 and 4

D. Runs 2 and 4

Refer to the graphs below. http://www.macmillanhighered.com/brainhoney/Resource/6274028,8,0,0,0/Assets/resources/ch10_summative_quiz/q16-1.jpg The graphs were generated from photosynthesis rate data collected at varying temperatures from two species of plants measured under different CO2 levels. Match the correct labels to the graphs. A. W = low; X = high; Y = C3 plant; Z = C4 plant B. W = high; X = low; Y = C3 plant; Z = C4 plant C. W = high; X = low; Y = CAM plant; Z = C3 plant D. W = low; X = high; Y = C4 plant; Z= C3 plant E. W = low; X = high; Y = C3 plant; Z = CAM plant

D. W = low; X = high; Y = C4 plant; Z= C3 plant

Which effector of enzyme activity is least likely to be utilized by cells? A. Allosteric inhibitors B. Allosteric activators C. Competitive inhibitors D. Noncompetitive inhibitors E. Irreversible inhibitors

E. Irreversible inhibitors

Chapter 8 quiz

answers

Suppose you are constructing a diagram to show the results of experiments with vesicles made to contain both bacteriorhodopsin and ATP synthase. What would the diagram show? A. It would show light stimulating ATP synthase to catalyze formation of ATP, which then drives the pumping of hydrogen ions into the vesicle interior by bacteriorhodopsin. B. It would show light stimulating bacteriorhodopsin to pump hydrogen ions into the vesicle, which then move back outside the vesicle through ATP synthase, causing it to catalyze ATP formation. C. It would show light stimulating ATP synthase to pump hydrogen ions out of the vesicle, which then cause the formation of ATP as they move back into the vesicle interior through bacteriorhodopsin. D. It would show light stimulating bacteriorhodopsin to pump hydrogen ions out of the vesicle, which then move back into the vesicle interior through ATP synthase, causing it to catalyze ATP formation.

B. It would show light stimulating bacteriorhodopsin to pump hydrogen ions into the vesicle, which then move back outside the vesicle through ATP synthase, causing it to catalyze ATP formation.

Why is oxygen important in the electron transport pathway and ATP synthesis? A. Oxygen combines with hydrogen to produce water, a molecule that is essential for life. B. Oxygen accepts electrons at the end of the electron transport chain to free the pathway for a new set of electrons. C. Oxygen is needed to drive the formation of ATP by ATP synthase. D. Oxygen donates electrons to the electron transport chain, initiating the electron transport process.

B. Oxygen accepts electrons at the end of the electron transport chain to free the pathway for a new set of electrons.

Certain types of cells have very low levels of metabolic activity for long time periods, but then rapidly shift to grow and divide. To undergo this shift, these cells must activate anabolic pathways. Which is one way they are able to accomplish this? A. Large molecules influence metabolic flux through competitive inhibition effects on enzymes. B. Small molecules affect metabolic flux through allosteric effects on enzymes. C. Anabolic enzymes inhibit catabolic enzymes. D. Cells begin directing all of their energy toward reactions with negative ΔGs. E. Cells only synthesize anabolic enzymes and cease synthesizing catabolic enzymes.

B. Small molecules affect metabolic flux through allosteric effects on enzymes.

7. In the complete oxidation of glucose, six CO2 molecules are formed per glucose molecule. The number of CO2 molecules released by glycolysis is _______, by pyruvate oxidation is _______, and by the citric acid cycle is _______. A. zero; zero; six B. zero; two; four C. one; one; four D. one; two; three E. two; two; two

B. zero; two; four

The binding of a substrate to an enzyme A. is always covalent. B. is irreversible. C. is nonspecific. D. may involve hydrogen bonds and van der Waals interactions. E. does not induce shape changes in the enzyme.

D. may involve hydrogen bonds and van der Waals interactions.

In addition to driving the synthesis of ATP and the reduction of NADP+ to NADPH, light stimulates the Calvin cycle by _______ and _______. A. decreasing the pH of the stroma; reduction of some Calvin cycle enzymes B. increasing the pH of the stroma; reduction of some Calvin cycle enzymes C. increasing the pH of the stroma; oxidation of some Calvin cycle enzymes D. decreasing the pH of the stroma; oxidation of some Calvin cycle enzymes E. increasing the pH of the thylakoid lumen; reduction of some Calvin cycle enzymes

.B. increasing the pH of the stroma; reduction of some Calvin cycle enzymes

Refer to the table below. Researchers set up test systems similar to those shown in the tutorial. They used vesicles with and without ATP synthase incorporated into their membranes. The vesicles were placed in various solutions to establish a range of pH conditions as shown in the table. Which test systems would be expected to produce ATP? A. 2 only B. 2 and 4 C. 2 and 6 D. 4 and 6

A . 2 only

18. Which is a viable path that a carbon atom could take as it moves through metabolic pathways in a cell? A. Amino acid → purine → DNA → purine → amino acid → acetyl CoA → fatty acid → triglyceride B. Glucose → glycerol → triglyceride → fatty acid → purine → DNA → pyrimidine → amino acid C. Pyrimidine → fatty acid → purine → amino acid → acetyl CoA → glucose → pyruvate → lactic acid D. Fatty acid → amino acid → pyrimidine → purine → glucose → glycerol → acetyl CoA → amino acid E. Amino acid → acetyl CoA → purine → pyrimidine → glycerol → fatty acid → lactic acid → glucose

A. Amino acid → purine → DNA → purine → amino acid → acetyl CoA → fatty acid → triglyceride

Refer to the table below summarizing how several compounds can be effective as herbicides. http://www.macmillanhighered.com/brainhoney/Resource/6274028,8,0,0,0/Assets/resources/ch10_summative_quiz/q8-1.jpg Which compound or compounds applied to a green plant would not change the plant's ability to carry out chemiosmosis, and which compound or compounds would not change the plant's ability to produce NADPH? Assume that the plant uses both cyclic and noncyclic photophosphorylation systems. A. Compound A would not change the plant's ability to carry out chemiosmosis, and compound C would not change the plant's ability to produce NADPH. B. Compounds A and D would not change the plant's ability to carry out chemiosmosis, and compounds B and C would not change the plant's ability to produce NADPH. C. Compound D would not change the plant's ability to carry out chemiosmosis, and compound B would not change the plant's ability to produce NADPH. D. Compound C would not change the plant's ability to carry out chemiosmosis, and compound A would not change the plant's ability to produce NADPH. E. Compounds B and D would not change the plant's ability to carry out chemiosmosis, and compounds A and C would not change the plant's ability to produce NADPH.

A. Compound A would not change the plant's ability to carry out chemiosmosis, and compound C would not change the plant's ability to produce NADPH.

A. Energy in the form of reduced carrier molecules is transferred to the high energy phosphate bonds of ATP. B. Energy in the form of carbon-carbon bonds is transferred via oxidation-reduction reactions that produce high-energy reduced carrier molecules. C. Energy in the form of reduced carrier molecules is transferred to the high-energy bonds of water. D. Energy in the form of carbon-carbon bonds is transferred to form a proton gradient, which is a useable form of energy for the cell.

A. Energy in the form of reduced carrier molecules is transferred to the high energy phosphate bonds of ATP.

Which statement about the citric acid cycle is false? A. It releases less energy than glycolysis. B. CO2 is released during operation of the cycle. C. It takes place in the mitochondrial matrix. D. It requires NAD+ and FAD. E. It does not operate under anaerobic conditions.

A. It releases less energy than glycolysis.

Consider two enzyme reaction solutions. Solution 1 has a ratio of enzyme to substrate of 1:100. Solution 2 has a ratio of enzyme to substrate of 100:1. Both solutions contain the same quantity of enzyme. Which reaction gives the greater reaction rate, and why? A. Solution 1, because the enzyme has much more available substrate than in solution 2. B. Solution 1, because the enzyme has much less available substrate than in solution 2. C. Solution 2, because the enzyme is saturated in this solution but not in solution 1. D. Solution 2, because the enzyme is not saturated in this solution but is saturated in solution 1. E. Both have the same reaction rate, because they contain the same quantity of enzyme.

A. Solution 1, because the enzyme has much more available substrate than in solution 2.

When purified cytochrome oxidase is exposed to cyanide, the cyanide binds reversibly and with high affinity to the enzyme's active site. What will be the likely outcome if mitochondria are exposed to high levels of cyanide? A. The cyanide will prevent movement of electrons along the electron transport chain. B. The cyanide will block movement of protons across the inner mitochondrial membrane. C. The cyanide will inhibit transfer of electrons from NADH to initiate electron transport. D. The cyanide will prevent oxygen from reaching the mitochondrial matrix.

A. The cyanide will prevent movement of electrons along the electron transport chain.

Which statement disagrees with the second law of thermodynamics? A. The disorder of a system and its surroundings decreases overall with time. B. Chemical energy may be converted to light energy. C. Only a portion of the total energy of a system is available to do work. D. Potential energy may be used to do work. E. During energy conversion, some energy can be lost as heat.

A. The disorder of a system and its surroundings decreases overall with time.

A biochemist generates an enzyme activity curve for an unknown enzyme. The curve is shown below. (http://www.macmillanhighered.com/brainhoney/Resource/6274028,8,0,0,0/Assets/resources/ch08_summative_quiz/q19-1.jpg) Which statement best explains the shape of this curve? A. The enzyme has multiple active sites. As the enzyme binds substrate at one site, its affinity for binding substrate at other active sites increases. B. The enzyme has a single active site. As the enzyme binds substrate, the activity of the enzyme stalls until it can clear the active site. C. The enzyme has multiple active sites. As the substrate concentration increases, all sites must be equally bound for the reaction to proceed. D. The enzyme has multiple active sites. Substrate binding at each of the sites is dependent upon the temperature of the reaction. E. The enzyme has a single active site. Substrate binding at this particular site occurs within a narrow pH range, termed the equivalence point.

A. The enzyme has multiple active sites. As the enzyme binds substrate at one site, its affinity for binding substrate at other active sites increases.

Refer to the table below. (http://www.macmillanhighered.com/brainhoney/Resource/6274028,8,0,0,0/Assets/resources/ch08_summative_quiz/q9-1.jpg ) A student prepared the table to summarize information she had learned about biological catalysts. Which statement best evaluates the accuracy of the information in the table? A. The table is accurate as written. B. Information in columns 2 and 3 should be switched. C. Information in columns 2 and 4 should be switched. D. Information in column 1 is incorrect. E. Information in column 5 is incorrect.

A. The table is accurate as written.

Suppose the reaction A → B has a large negative ΔG. The reaction would proceed _______, at equilibrium _______ would be present, and _______. A. from A to B; mostly B; insufficient information is given to predict the rate of the reaction B. from B to A; mostly A; the reaction would be slow C. from A to B; mostly B; the reaction would be fast D. from A to B; mostly B; the reaction would be slow E. There is not enough information to answer the question.

A. from A to B; mostly B; insufficient information is given to predict the rate of the reaction

. In oxygenic photosynthesis, water is A. oxidized to oxygen gas (O2) in the light. B. reduced to hydrogen gas (H2) in the light. C. oxidized to oxygen gas (O2) in the dark. D. reduced to hydrogen gas (H2) in the dark. E. reduced to oxygen gas (O2) in the light.

A. oxidized to oxygen gas (O2) in the light.

15. Fermentation A. results in the formation of either lactic acid or ethanol. B. completely oxidizes glucose to CO2 and H2O. C. does not involve substrate-level ADP synthesis. D. occurs under aerobic conditions in yeasts. E. is endergonic.

A. results in the formation of either lactic acid or ethanol.

Refer to the sketch of a chloroplast and the two chemical equations below. http://www.macmillanhighered.com/brainhoney/Resource/6274028,8,0,0,0/Assets/resources/ch10_summative_quiz/q2-1.jpg Equation 1: 3 CO2 + 9 ATP + 6 NADPH + 5 H2O ◊ G3P + 9 ADP + 9 Pi + 6 NADP+ + 2 H+ Equation 2: 2 H2O + 3 ADP + 3 Pi + 2 NADP+ ◊ O2 + 3 ATP + 2 NADPH Match the structure/location in the chloroplast with its name and the chemical reaction that takes place there. A. A = thylakoids, equation 1; B = stroma, equation 2 B. A = thylakoids, equation 2; B = stroma, equation 1 C. A = stroma, equation 1; B = thylakoids, equation 2 D. A = thylakoids, equations 1 and 2; B = stroma E. A = thylakoids; B = stroma, equations 1 and 2

B. A = thylakoids, equation 2; B = stroma, equation 1

Many vitamins are essential to human health because they are precursors for coenzymes. Many are also compounds that human cells cannot synthesize themselves and so must be obtained through diet. What would happen if a person could not obtain one of these vitamins from a food source? A. An enzyme would not fold properly, making it unable to catalyze a vital metabolic reaction. B. An enzyme would lack a critical chemical component required as a participant in the enzyme's metabolic reaction. C. An enzyme would lack a metal ion at its active site that enables the enzyme to carry out its catalytic mechanism. D. An enzyme would lose its ability to bind substrates, making it unable to catalyze an essential chemical reaction. E. An enzyme would lose its substrate specificity, causing it to catalyze many extra reactions that normally do not occur in a cell.

B. An enzyme would lack a critical chemical component required as a participant in the enzyme's metabolic reaction.

20. Refer to the figure, showing allosteric regulation of glycolysis and the citric acid cycle. http://www.macmillanhighered.com/brainhoney/Resource/6274028,8,0,0,0/Assets/resources/ch09_summative_quiz/Life11eSQ_Ch09_Q20.jpg If a cell is fed a large supply of fatty acids, which outcome can be expected? A. Glycolysis and pyruvate oxidation will be stimulated, causing citrate to build up and activate fatty acid synthase. B. Oxidation of fatty acids through the citric acid cycle will be stimulated until ATP builds up and inhibits citrate synthase, diverting fatty acids into storage molecules such as triglycerides. C. Glycolysis will be stimulated and pyruvate oxidation will be inhibited as acetyl CoA builds up to high levels in the cell. D. The excess fatty acids will deplete the oxygen supply, causing everything except glycolysis to shut down and activating the lactic acid fermentation pathway. E. Oxidation of fatty acids to form acetyl CoA will be stimulated, which will stimulate gluconeogenesis to form glucose that the cell can store as an energy resource.

B. Oxidation of fatty acids through the citric acid cycle will be stimulated until ATP builds up and inhibits citrate synthase, diverting fatty acids into storage molecules such as triglycerides.

Refer to the table below showing observations from experiments conducted on three types of pea plants. One type of pea plant contained a mutation in the gene encoding thioredoxin that resulted in zero production of the protein thioredoxin. Another type contained two mutations: the same thioredoxin mutation as in the previous type and a mutation in the gene encoding the Calvin cycle enzyme phosphoribulokinase (PRK) that did not affect its expression. The third type contained no mutations in either gene and was designated as "wild type." Before the experiments, all plants were kept on a 14-hour light/10-hour dark cycle for several weeks. http://www.macmillanhighered.com/brainhoney/Resource/6274028,8,0,0,0/Assets/resources/ch10_summative_quiz/q13-1.jpg In conducting the experiments, researchers excised leaves either toward the end of a light cycle or toward the end of a dark cycle. Chloroplasts were then isolated and lysed to release the contents of the stroma, and PRK was assayed to determine its catalytic activity. Which statement about thioredoxin is consistent with these data? A. Thioredoxin is an electron carrier protein that participates in the electron transport chain during photophosphorylation. B. Thioredoxin is a regulatory molecule, becoming activated via light-induced changes and then activating PRK by shifting it from an inactive to an active conformation. C. Thioredoxin is a regulatory molecule, shutting down Calvin cycle reactions by acting as an alternative to NADP+ as the final electron acceptor during the light reactions. D. Thioredoxin is an enzyme that functions in carbon fixation as an alternative to the Calvin cycle enzyme rubisco. E. Thioredoxin is an integral protein component of the thylakoid membrane that ensures that the membrane remains impermeable to protons.

B. Thioredoxin is a regulatory molecule, becoming activated via light-induced changes and then activating PRK by shifting it from an inactive to an active conformation.

16. A suspension of yeast supplied with glucose as its source of energy was transferred from an aerobic environment to an anaerobic one. Which result would you predict for the rate of glucose utilization and the rate of ethanol production after the transfer? Assume that the yeast must expend the same amount of energy to survive in both environments. A. Glucose usage would decrease, and ethanol production would increase. B. Glucose usage would increase, and ethanol production would decrease. C. Both glucose usage and ethanol production would increase. D. Neither glucose usage nor ethanol production would change. E. Glucose usage would not change, and ethanol production would increase.

C. Both glucose usage and ethanol production would increase.

Which statement can be used to explain how the first law of thermodynamics relates to biological systems? A. Biological systems must take in energy from the surroundings to be able to build complex molecules from smaller precursor molecules. B. In any biological system, the total energy includes the usable energy that can do work and the unusable energy that is lost to disorder. C. Energy moves in and out of biological systems and is transformed from one type to another, but no energy is destroyed or created in the process. D. The amount of energy that a biological system has available to do work is always less than the original amount of energy taken in by the system from its surroundings. E. In a biological system, free energy continually decreases with repeated energy transformations.

C. Energy moves in and out of biological systems and is transformed from one type to another, but no energy is destroyed or created in the process.

Which is the correct sequence of electron transport proteins in the respiratory chain? A. Ubiquinone → cytochrome c reductase → cytochrome c → cytochrome c oxidase → NADH-Q reductase B. NADH-Q reductase → ubiquinone → cytochrome c → cytochrome c oxidase → cytochrome c reductase C. NADH-Q reductase → ubiquinone → cytochrome c reductase →cytochrome c → cytochrome c oxidase D. Ubiquinone → NADH-Q reductase →cytochrome c reductase → cytochrome c → cytochrome c oxidase

C. NADH-Q reductase → ubiquinone → cytochrome c reductase →cytochrome c → cytochrome c oxidase NURCO

Refer to the table below, which summarizes similarities and differences between cyclic and noncyclic photophosphorylation. http://www.macmillanhighered.com/brainhoney/Resource/6274028,8,0,0,0/Assets/resources/ch10_summative_quiz/q7-1.jpg Which statement corrects an inaccuracy present in this table? A. Cyclic photophosphorylation uses photosystem II, not photosystem I. B. Both types of photophosphorylation can support Calvin cycle reactions. C. Only noncyclic photophosphorylation uses water as an electron donor. D. Both types of photophosphorylation produce oxygen as a product. E. ATP is produced only during cyclic photophosphorylation.

C. Only noncyclic photophosphorylation uses water as an electron donor.

Which are biological examples of potential energy (PE) and kinetic energy (KE)? A. PE = concentration gradient; KE = chemical bonds B. PE = muscle contraction; KE = electrical charge imbalance C. PE = chemical bonds; KE = ion movement across a membrane D. PE = electrical charge imbalance; KE = concentration gradient E. PE = protein conformational change; KE = muscle contraction

C. PE = chemical bonds; KE = ion movement across a membrane

The immediate source of energy for ATP synthesis in chloroplasts is _______, while the ultimate source of energy for ATP synthesis in chloroplasts is _______. A. light; electron transport B. electron transport; a proton gradient C. a proton gradient; light D. NADPH; electron transport E. NADPH; energized chlorophylls

C. a proton gradient; light

19. Metabolic pathways can be controlled through the availability of enzymes and modulation of their catalytic activities. Enzyme availability can be regulated via _______, while enzyme activity is commonly regulated via _______. A. covalent modification; proteolytic breakdown B. allosteric activation and inhibition; covalent modification C. gene expression; allosteric activation and inhibition D. proteolytic breakdown; gene expression E. gene expression; covalent modification

C. gene expression; allosteric activation and inhibition

1. Refer to the table below. http://www.macmillanhighered.com/brainhoney/Resource/6274028,8,0,0,0/Assets/resources/ch09_summative_quiz/Life11eSQ-Ch09-Q01.jpg A student made this table as a study guide for learning the various catabolic pathways that cells use for harvesting energy from glucose. Which statement best evaluates the accuracy of the student's efforts? A. The citric acid cycle generates the greatest ATP yield per glucose molecule. B. While glycolysis occurs in the cytosols of prokaryotes, this pathway occurs in the mitochondrial matrix in eukaryotes. C. In eukaryotes, pyruvate oxidation is carried out in the mitochondrial matrix, not in the cytosol. D. Pyruvate oxidation and the citric acid cycle can operate in the absence of oxygen. E. Oxidation of NADH also occurs during glycolysis.

C.In eukaryotes, pyruvate oxidation is carried out in the mitochondrial matrix, not in the cytosol.

Refer to the graph below. (http://www.macmillanhighered.com/brainhoney/Resource/6274028,8,0,0,0/Assets/resources/ch08_summative_quiz/q12-1.png) The graph shows energy changes associated with a reaction that goes forward without an enzyme present. Which statement correctly describes what happens when an enzyme is added to catalyze the reaction? A. A changes and C does not change. B. B changes and C does not change. C. C changes and A does not change. D. A changes and B does not change. E. B changes and A does not change.

D. A changes and B does not change.

17. Which statement could be used as part of a description of how carbohydrate, lipid, and protein are linked through catabolic and anabolic pathways? A. Glycolysis and fermentation only partially oxidize glucose, while the citric acid cycle and oxidative phosphorylation allow for full oxidation of glucose and transfer of its free energy to ATP. B. Metabolic pathways for lipids, proteins, and carbohydrates all share the same characteristic, in that they represent a series of separate chemical reactions that together accomplish a complex chemical transformation. C. Metabolic pathways are compartmentalized in the cell, which allows physical boundaries to organize the large numbers of metabolic interconversions taking place at any one time in a cell. D. Glycolysis and the citric acid cycle occupy a central position in cell metabolism, connecting to lipid, protein, and carbohydrate breakdown and synthesis through small molecule intermediates. E. Metabolism is a cyclical process of energy conversion in which chemical energy is harvested from nutrients in catabolic reactions and used to synthesize new molecules in anabolic reactions.

D. Glycolysis and the citric acid cycle occupy a central position in cell metabolism, connecting to lipid, protein, and carbohydrate breakdown and synthesis through small molecule intermediates.

A chemical cross-linking reagent has two reactive ends that can be used to covalently link two different amino acid groups in proteins. The links that result are similar to a disulfide bridge that forms between two cysteine groups. Biochemists use chemical cross-linking reagents to test for conformational changes in proteins because the cross-links often freeze proteins in a single conformation. Which method of increasing reaction rates would be most adversely affected by chemical cross-linking? A. Metal ion catalysis B. Covalent catalysis C. Acid-base catalysis D. Induced-fit mechanism E. Substrate orientation

D. Induced-fit mechanism

5. Refer to the table, which summarizes the inputs and outputs of glycolysis. Which group represents the net outputs of glycolysis? http://www.macmillanhighered.com/brainhoney/Resource/6274028,8,0,0,0/Assets/resources/ch09_summative_quiz/q5-1.jpg A. Pyruvate, 2 NADH, 4 ATP, 2 ADP, 2 Pi B. 4 NADH, 2 ATP, 2 ADP, 2 Pi C. 2 NADH, 2 ATP, 2 ADP, 2 Pi D. Pyruvate, 2 NADH, 2 ATP E. Pyruvate, 2 NADH, 4 ATP

D. Pyruvate, 2 NADH, 2 ATP

14. Cyanide inhibits the enzyme in the mitochondrial electron transport chain that reduces O2 to water. Suppose you added cyanide to a suspension of muscle cells from a rat. Which statement is accurate with respect to the effects of cyanide on glucose catabolism? A. The citric acid cycle and glycolysis would be inhibited. B. The citric acid cycle would be inhibited, but glycolysis would not and so pyruvate would accumulate. C. Both the citric acid cycle and glycolysis would be stimulated. D. The citric acid cycle would be inhibited, but glycolysis would not and so lactic acid would accumulate. E. The citric acid cycle would not be inhibited, but glycolysis would.

D. The citric acid cycle would be inhibited, but glycolysis would not and so lactic acid would accumulate.

In the 1930s, researchers worked with green algae to experimentally determine the minimum light exposure in a single flash that produced the maximal oxygen output. When the researchers calculated the amount of chlorophyll present, they found that there were 300 times more chlorophyll molecules present than would be needed to produce this amount of oxygen with a single light flash. How are these observations consistent with the way that scientists today describe the light-harvesting complex in chloroplasts? A. The observations explain why most chlorophyll molecules are static and not reactive inside the light-harvesting complex. B. The observations explain why water is the source of oxygen that is produced during the reaction taking place inside one light-harvesting complex. C. The observations explain how energy is transferred from the light-harvesting complex to the Calvin cycle. D. The observations explain how most chlorophyll molecules act as antennae to absorb photons and then redirect this energy to a single chlorophyll molecule at the center of the complex. E. The observations explain how light energy is ultimately converted to chemical energy within the light-harvesting complex.

D. The observations explain how most chlorophyll molecules act as antennae to absorb photons and then redirect this energy to a single chlorophyll molecule at the center of the complex.

Enzyme Y is a component of a metabolic pathway and is inhibited by a metabolite produced at the end of that particular metabolic pathway. Which statement would not be true regarding this enzyme? A. This enzyme regulates the pathway through a feedback inhibition mechanism. B. This enzyme may also be activated by metabolites of another pathway. C. Levels of this enzyme may be regulated at the level of transcription of its gene. D. This enzyme uses competitive inhibition as a mechanism for its regulation by downstream metabolites in the pathway. E. This enzyme is very likely involved in the first commitment step of the metabolic pathway mentioned in the question.

D. This enzyme uses competitive inhibition as a mechanism for its regulation by downstream metabolites in the pathway.

The _______ of the mitochondrion contains the proteins making up the _______ that carry out electron transport. A. outer mitochondrial membrane; respiratory chain B. inner mitochondrial membrane; proton gradient C. mitochondrial intermembrane space; proton gradient D. inner mitochondrial membrane; respiratory chain

D. inner mitochondrial membrane; respiratory chain

9. The electron transport chain A. is the site of most reactions of the citric acid cycle. B. synthesizes ATP. C. pumps protons into the mitochondrial matrix during electron transport. D. oxidizes the intermediate electron carriers NADH and FADH2. E. oxidizes water to ½ O2 and 2 H+.

D. oxidizes the intermediate electron carriers NADH and FADH2.

Researchers developing herbicidal chemical agents tested one, compound Q, on the ability of chloroplasts isolated from spinach leaves to carry out three stages of photosynthesis under illumination. The results are shown in the table below. http://www.macmillanhighered.com/brainhoney/Resource/6274028,8,0,0,0/Assets/resources/ch10_summative_quiz/q10-1.jpg The table indicates the levels of activity in these photosynthesis stages. The number of "+" signs indicates the relative level of activity, while "0" indicates no activity. Which statement is consistent with these results? A. Compound Q binds to one of the electron carrier proteins in photosystem I and inhibits its ability to accept electrons. B. Compound Q inhibits NADP+ reductase, the enzyme that catalyzes the transfer of electrons in the formation of NADPH. C. Compound Q induces the light reactions and light-independent reactions to lose their dependency on light. D. Compound Q reverses the sequence of the light reactions and light-independent reactions. E. Compound Q allows protons to leak through the thylakoid membrane, disrupting the ability of the chloroplast to synthesize ATP required by the Calvin cycle.

E. Compound Q allows protons to leak through the thylakoid membrane, disrupting the ability of the chloroplast to synthesize ATP required by the Calvin cycle.

Which statement about the light-independent reactions of photosynthesis is false? A. The term "light-independent reactions" refers to the pathways by which CO2 is reduced to carbohydrates. B. Light-independent reactions take place in the chloroplast stroma. C. ATP is consumed by light-independent reactions. D. NADPH is consumed by light-independent reactions. E. Light-independent reactions operate in the dark.

E. Light-independent reactions operate in the dark.

10. Refer to the graph below. /brainhoney/Resource/6274028,8,0,0,0/Assets/resources/ch09_summative_quiz/Life11eSQ_Ch09_Q10.jpg Which statement about the respiratory chain best explains the information presented in the graph? http://www.macmillanhighered.com/brainhoney/Resource/6274028,8,0,0,0/Assets/resources/ch09_summative_quiz/Life11eSQ_Ch09_Q10.jpg A. During electron transport along the respiratory chain, protons are actively transported across the inner mitochondrial membrane to create a proton gradient. B. The gradient of protons established across the inner mitochondrial membrane as a result of electron transport is a source of potential energy. C. Extensive folding of the inner mitochondrial membrane allows a larger number of protein components in the respiratory chain than would otherwise fit. D. The movement of protons from a high concentration in the intermembrane space to a low concentration in the mitochondrial matrix is coupled to the synthesis of ATP from ADP and Pi. E. The components of the respiratory chain are arranged in order so that an electron passing from one to the next undergoes a sequential drop in energy.

E. The components of the respiratory chain are arranged in order so that an electron passing from one to the next undergoes a sequential drop in energy.

To be metabolized, glucose must be converted to glucose 6-phosphate. However, the phosphorylation of glucose to form glucose 6-phosphate is endergonic with a positive ΔG. How do cells circumvent this problem? A. The reaction is catalyzed by an enzyme, which allows the reaction to proceed by changing its ΔG. B. The reaction is catalyzed by an enzyme, which allows the reaction to proceed by lowering its activation energy. C. An enzyme raises the activation energy barrier to favor glucose 6-phosphate formation. D. An enzyme changes the equilibrium constant for the reaction to favor glucose 6-phosphate formation. E. The reaction is coupled to the hydrolysis of ATP, making the entire process exergonic.

E. The reaction is coupled to the hydrolysis of ATP, making the entire process exergonic.

12. Refer to the figure below. http://www.macmillanhighered.com/brainhoney/Resource/6274028,8,0,0,0/Assets/resources/ch09_summative_quiz/Life11eSQ_Ch09_Q12.jpg Does this figure have any inaccuracies? A. No, the figure is accurate as shown. B. Yes, the electrons are shown moving up as they pass along the respiratory chain but they should be shown moving down along the chain. C. Yes, the arrows showing movement of protons from the matrix into the inner membrane are all pointing in the wrong direction and should be reversed. D. Yes, the position of ATP synthase relative to the inner membrane is incorrect and should be reversed so that ATP is shown being synthesized in the intermembrane space. E. Yes, the arrow showing movement of protons through ATP synthase is pointing in the wrong direction; it should be reversed.

E. Yes, the arrow showing movement of protons through ATP synthase is pointing in the wrong direction; it should be reversed.

When the ratio of O2 to CO2 within their leaves _______, C3 plants undergo a shift toward more _______ and less _______. A. increases; carbon fixation; photorespiration B. decreases; photorespiration; carbon fixation C. increases; growth; carbon fixation D. decreases; photorespiration; growth E. increases; photorespiration; carbon fixation

E. increases; photorespiration; carbon fixation

Enzymes increase the rate of a reaction in all of the following ways except A. orienting substrates. B. inducing strain on the substrate. C. reacting chemically with the substrate. D. donating a proton to the substrate. E. permanently binding the substrate.

E. permanently binding the substrate.