AP Bio Chapter 6

The figure shows the structure of a coenzyme. Which number indicates a chemical bond in this structure that is typically involved in transfer of energy within cells? a. 1 b. 2 c. 3 d. 4 e. 5

a. 1

How many glyceraldehyde-3-phosphate (G3P) molecules are produced by the Calvin cycle when 18 CO2 are fixed? a. 6 b. 9 c. 18 d. 36 e. 44

a. 6

Which molecules should be placed at locations A, B, and C on the figure above to complete this model? a. A and C: ATP and reduced coenzymes; B: ADP and oxidized coenzymes b. A and B: ATP and reduced coenzymes; C: ADP and oxidized coenzymes c. A and C: ATP and oxidized coenzymes; B: ADP and reduced coenzymes d. A and B: ATP and oxidized coenzymes; C: ADP and reduced coenzymes e. B and C: ATP and reduced coenzymes; A: ADP and oxidized coenzymes

a. A and C: ATP and reduced coenzymes; B: ADP and oxidized coenzymes

Which reactions are exergonic? a. AH → A and NADH → NAD+ b. AH → A and NAD+ → NADH c. AH → A and B → BH d. B → BH and NADH → NAD+ e. B → BH and NAD+ → NADH

a. AH → A and NADH → NAD+

Which statement regarding the Calvin cycle is false? a. ATP is required during carbon fixation. b. NADPH is required for reduction and sugar production. c. Six turns of the cycle are required for every glucose molecule later produced in non-Calvin cycle reactions. d. Twelve NADPH are required for every 6 CO2 fixed. e. The most intensive energy phase is reduction and sugar production.

a. ATP is required during carbon fixation.

Which equation does not represent an oxidation-reduction reaction? a. C6H12O6 + 6 O2 → 6 CO2 + 6 H2O b. ADP + Pi → ATP + H2O c. NADH + H+ + ? O2 → NAD+ + H2O d. CH4 + ? O2 → CH3OH + H+ e. C3H6O3 + NAD+ → C3H4O3 + NADH + H+

b. ADP + Pi → ATP + H2O

How are ATP and NADH similar? a. The same quantity of free energy is released per molecule of ATP or NADH. b. Both structures contain a ribose sugar, an adenine ring, and more than one phosphate group. c. Both ATP and NADH function as reducing agents in metabolic reactions. d. They are interchangeable energy carriers, allowing the cell to use whichever molecule is in greatest abundance as a source of energy. e. Both molecules are oxidized by molecular oxygen (O2) in reactions that release energy for use by the cell.

b. Both structures contain a ribose sugar, an adenine ring, and more than one phosphate group.

Which class of compounds is a direct product of photosynthesis? a. Lipids b. Carbohydrates c. Proteins d. Fatty acids e. Sterols

b. Carbohydrates

The reactions making up the citric acid cycle are important because they capture free energy in the form of a. FADH2 and NADH. b. GTP, FADH2, and NADH. c. ATP. d. citric acid. e. CO2.

b. GTP, FADH2, and NADH.

In the complete oxidation of glucose, 6 CO2 molecules are formed per glucose molecule oxidized. From the list below, choose the correct numbers of CO2 molecules released by glycolysis (Gly), the citric acid cycle (CAC), and pyruvate oxidation (Pyr). a. Gly 1; CAC 3; Pyr 2 b. Gly 0; CAC 4; Pyr 2 c. Gly 1; CAC 4; Pyr 1 d. Gly 2; CAC 2; Pyr 2 e. Gly 0; CAC 6; Pyr 0

b. Gly 0; CAC 4; Pyr 2

Various aspects of plant function were tested in the presence and absence of Compound X, an effective herbicide. The results of the tests are shown in the table above. Which hypothesis about Compound X is consistent with the data? a. It binds to chlorophyll molecules and prevents them from absorbing light. b. It binds to an electron transport protein and prevents it from transferring electrons. c. It uncouples ATP synthesis from chemiosmosis. d. It inhibits proton gradient formation in Photosystem II. e. It blocks the transfer of electrons from water to a reaction center.

b. It binds to an electron transport protein and prevents it from transferring electrons.

How is free energy that is captured in the molecules NADH and FADH2 passed on in the cell? a. It is used to reduce oxygen. b. It is used to establish a proton gradient across a membrane. c. It is used to phosphorylate ADP via substrate level phosphorylation. d. It is used to drive the citric acid cycle. e. It is used to oxidize another round of glucose molecules.

b. It is used to establish a proton gradient across a membrane.

Which progression shows a ranking of light from lowest energy to highest energy? a. Infrared light, blue light, yellow light, X rays, microwaves b. Microwaves, infrared light, yellow light, blue light, X rays c. X rays, yellow light, blue light, infrared light, microwaves d. Microwaves, infrared light, blue light, yellow light, X rays e. X rays, blue light, yellow light, infrared light, microwaves

b. Microwaves, infrared light, yellow light, blue light, X rays

Which organelle contains enzymes necessary for aerobic cellular energy production in eukaryotes? a. Nucleus b. Mitochondria c. Golgi apparatus d. Peroxisomes e. Lysosomes

b. Mitochondria

Reduced electron carriers are critical to the citric acid cycle because a. NADH and FADH2 can donate their electrons to the electron transport chain and be regenerated to allow glycolysis to continue. b. NADH and FADH2 can donate their electrons to the electron transport chain and be regenerated to allow the citric acid cycle to continue. c. FADH2 can donate its electrons to the electron transport chain and be regenerated to allow glycolysis to continue. d. ATP can donate its electrons to the electron transport chain and be regenerated to allow the citric acid cycle to continue. e. GTP, NADH, and FADH2 can donate their electrons to the electron transport chain and be regenerated to allow the citric acid cycle to continue.

b. NADH and FADH2 can donate their electrons to the electron transport chain and be regenerated to allow the citric acid cycle to continue.

Which reaction is not an oxidation-reduction reaction? a. NADH + ? O2 + H+ ↔ NAD+ + H2O b. R—CH=CH—CH3 + H2O ↔ RCH2—CH(OH)—CH3 c. FAD + H2O ↔ FADH2 + ? O2 d. NADH + acetaldehyde ↔ NAD+ + ethanol e. AH2 + B ↔ A + BH2

b. R—CH=CH—CH3 + H2O ↔ RCH2—CH(OH)—CH3

Which statement about ATP is true? a. The synthesis of ATP is an energy-neutral reaction. b. The hydrolysis of ATP to ADP and Pi is an exergonic reaction. c. The phosphate bond energy of ATP is used to power catabolic metabolism. d. ATP is a building block of protein. e. The phosphate bond energy of ATP may be transformed into the energy in a magnetic field.

b. The hydrolysis of ATP to ADP and Pi is an exergonic reaction.

What would happen if regeneration of NAD+ were inhibited during lactic acid fermentation? a. The rate of glucose converted to pyruvate would increase. b. The rate of lactic acid production would decrease. c. The rate of pyruvate production would remain the same. d. The concentration of NAD+ would increase. e. The concentration of lactate dehydrogenase would increase.

b. The rate of lactic acid production would decrease.

Fermentation is a process that occurs a. in muscle tissue when there is a sufficient supply of oxygen. b. in many organisms, including plants and vertebrates. c. in mitochondria. d. in the absence of both NAD+ and NADH. e. in single-celled organisms only.

b. in many organisms, including plants and vertebrates.

Under anaerobic conditions, pyruvate a. is converted to lactate or tricarboxylic acids. b. is fermented to lactate or alcohol. c. enters the citric acid cycle. d. is reduced to lactate as the final end product. e. is broken down on the plasma membrane.

b. is fermented to lactate or alcohol.

Light is needed for photosynthesis, because it a. brings water into the chloroplast. b. provides energy, which is converted to chemical energy. c. directly causes ATP production. d. provides heat energy, which is converted to chemical energy. e. drives many enzymatic reactions.

b. provides energy, which is converted to chemical energy.

The immediate source of energy for ATP synthesis in chloroplasts is a. electron transport. b. the electrochemical proton gradient. c. light. d. energized chlorophylls. e. NADPH.

b. the electrochemical proton gradient.

An action spectrum measures a. the relative rate of photosynthesis as a function of time. b. the relative rate of photosynthesis as a function of wavelength. c. the relative absorption of light as a function of wavelength. d. the relative absorption of light as a function of time. e. the relative absorption of light of a chlorophyll molecule as a function of wavelength.

b. the relative rate of photosynthesis as a function of wavelength.

Where does glycolysis occur in the eukaryotic cell? a. Cell membrane b. Cytosol c. Mitochondrial matrix d. Nucleus e. Mitochondrial membrane

b. Cytosol

For each glucose molecule being oxidized, the citric acid cycle produces a. 2 CO2. b. 8 NADH. c. 2 FADH2. d. 6 ATP. e. 3 GTP.

c. 2 FADH2.

In the early 1880s, German scientist Theodor Engelmann combined a photosynthetic filamentous alga with aerobic, oxygen-seeking bacteria in a tube of water. The alga was long and narrow and lined up in the same direction as the long tube, while the bacteria were much smaller and moved freely within the tube. When Engelmann exposed the tube to white light, the bacteria moved about randomly. When he placed a prism between the light and the tube, the bacteria gathered in two distinct regions along the length of the filamentous alga that corresponded to different colors of light from the prism. What did Engelmann's experiment demonstrate? a. Photophosphorylation b. Photosystems I and II c. An action spectrum d. An absorbance spectrum e. Electron transport

c. An action spectrum

Which sequence describes the general flow of free energy in the cell? a. Catabolic reactions → phosphoanhydride bond of ATP → NAD+ reduction → anabolic reactions b. Catabolic reactions → NAD+ reduction → anabolic reactions → phosphoanhydride bond of ATP c. Catabolic reactions → NAD+ reduction → phosphoanhydride bond of ATP → anabolic reactions d. Anabolic reactions → NAD+ reduction → phosphoanhydride bond of ATP → catabolic reactions e. Anabolic reactions → phosphoanhydride bond of ATP → NAD+ reduction → catabolic reactions

c. Catabolic reactions → NAD+ reduction → phosphoanhydride bond of ATP → anabolic reactions

Which statement regarding glycolysis is true? a. Two molecules of glucose are catabolized to form two molecules of pyruvate. b. The entire process is endergonic. c. Energy from ATP must be expended in the early steps. d. ATP is not formed. e. NADH is not formed.

c. Energy from ATP must be expended in the early steps.

What is the cellular location of the citric acid cycle? a. Cell membrane b. Cytosol c. Mitochondrial matrix d. Mitochondrial inner membrane e. Mitochondrial inner membrane space

c. Mitochondrial matrix

Which statement about ATP is true? a. ATP is required to drive all metabolic reactions in the cell. b. ATP hydrolysis releases energy that the cell can use to drive exergonic reactions. c. ATP cannot be regenerated once its free energy has been released, so the cell processes it as waste. d. ATP functions as a mobile energy carrier molecule in a cell and is made in several different ways. e. ATP can be generated from ADP and inorganic phosphate if this reaction is coupled to another synthesis reaction.

d. ATP functions as a mobile energy carrier molecule in a cell and is made in several different ways.

Which progression represents a path that a carbon atom could follow? a. Starch in plant → glucose in cow → CO2 in atmosphere → glucose in rabbit → protein in rabbit → CO2 in atmosphere b. CO2 in atmosphere → glucose in cow → CO2 in atmosphere → glucose in plant → protein in cow c. Glucose in cow → CO2 in atmosphere → glucose in plant → CO2 in atmosphere → protein in cow d. CO2 in atmosphere → glucose in plant → starch in plant → glucose in cow → protein in cow e. Starch in plant → CO2 in atmosphere → protein in rabbit → glucose in rabbit → CO2 in atmosphere

d. CO2 in atmosphere → glucose in plant → starch in plant → glucose in cow → protein in cow

In the citric acid cycle, carbon atoms end up as a. glyceraldehyde. b. pyruvate. c. acetyl CoA. d. CO2. e. citrate.

d. CO2.

Mouse mitochondria were isolated and incubated with two different compounds known to shut down cellular respiration. During the incubations, the mitochondria were tested to see if they could oxidize NADH and/or produce ATP. The results are summarized in the table. Which statement is consistent with these data? a. Compound X inhibits the citric acid cycle while Compound Y inhibits ATP synthase. b. Compound X inhibits electron movement along the electron transport chain, while Compound Y inhibits the citric acid cycle. c. Compound X inhibits ATP synthase, while Compound Y inhibits the citric acid cycle. d. Compound X inhibits ATP synthase, while Compound Y inhibits electron movement along the electron transport chain. e. Compound X inhibits electron movement along the electron transport chain, while Compound Y inhibits ATP synthase.

d. Compound X inhibits ATP synthase, while Compound Y inhibits electron movement along the electron transport chain.

Which statement about the citric acid cycle is true? a. It releases less energy than glycolysis. b. CO2 is absorbed during operation of the cycle. c. It takes place in the mitochondrial outer membrane. d. It requires NAD+ and FAD. e. It operates under anaerobic conditions.

d. It requires NAD+ and FAD.

Which process is responsible for the largest amount of ATP production during cellular respiration? a. Glycolysis b. Pyruvate oxidation c. Citric acid cycle d. Oxidative phosphorylation e. Substrate-level phosphorylation

d. Oxidative phosphorylation

Which statement best explains why the two spectra shown are not identical? a. Some of the light energy absorbed by a reaction center is converted to heat, while most is converted to chemical energy in accord with the first law of thermodynamics. b. Chlorophyll present in each reaction center absorbs some wavelengths of light and transmits other wavelengths. c. Reaction centers are more efficient at converting energy from certain wavelengths of light into chemical energy and less efficient at converting energy from other wavelengths. d. The spectrum of light absorption by a leaf is much broader than that of chlorophyll alone, partly due to the presence of carotenoids that also absorb light. e. Pigments called carotenoids reflect light of wavelengths not absorbed by chlorophyll and prevent this energy from entering photosystems.

d. The spectrum of light absorption by a leaf is much broader than that of chlorophyll alone, partly due to the presence of carotenoids that also absorb light.

The chemiosmotic mechanism explains a. the coupling of glycolysis to the citric acid cycle. b. how ATP is produced in the cytosol. c. how water flows into and out of the mitochondria. d. how a proton gradient is coupled to ATP production. e. why membranes are not needed for ATP production.

d. how a proton gradient is coupled to ATP production.

Glycolysis a. is the conversion of glucose to two molecules of lactate. b. is an endergonic reaction. c. results in the net consumption of ATP. d. is an oxidation-reduction process. e. releases carbon dioxide.

d. is an oxidation-reduction process.

The mitochondrial ATP synthase a. is an entirely integral membrane protein. b. couples the synthesis of ATP to the flow of protons across the inner membrane from the mitochondrial matrix to the intermembrane space. c. is a soluble protein located in the mitochondrial matrix. d. makes ATP at the expense of the proton gradient established by electron transport. e. usually hydrolyzes ATP to establish a proton gradient.

d. makes ATP at the expense of the proton gradient established by electron transport.

The difference between oxidation and reduction is that a. oxidation involves a gain of electrons, while reduction involves a loss of electrons. b. oxidation can happen by itself, while reduction must be coupled to another reaction. c. an oxidized compound has more electrons than the reduced form of the same compound. d. oxidation reduces the number of electrons in a reactant, while reduction increases the number of electrons. e. oxidation involves transfer of two electrons between reactants, while reduction involves transfer of one electron.

d. oxidation reduces the number of electrons in a reactant, while reduction increases the number of electrons.

The major product of photosynthesis that is exported from the leaves to the rest of the plant is/are a. glucose. b. amino acids. c. starch. d. sucrose. e. nucleotides.

d. sucrose.

The most important wavelengths of light for photosynthesis are a. the UV wavelengths. b. the visible wavelengths only between 400 and 525 nm. c. the IR wavelengths. d. the visible wavelengths between 400 and 525 nm and between 600 and 700 nm. e. the visible wavelengths only between 600 and 700 nm.

d. the visible wavelengths between 400 and 525 nm and between 600 and 700 nm.

Which statement best characterizes the properties of a photosystem? a. A photosystem consists of antennae pigments only. b. Photosystems do not contain proteins. c. A photosystem consists of reaction center chlorophylls only. d. There is only one photosystem in green plants. e. A photosystem is a complex of pigments, proteins, and reaction center chlorophyll.

e. A photosystem is a complex of pigments, proteins, and reaction center chlorophyll.

Reduction of carbon dioxide to the level of carbohydrates relies on energy from a. ATP only. b. NADP+ only. c. ATP and NADP+. d. NADPH only. e. ATP and NADPH.

e. ATP and NADPH.

What role does water play in photosynthesis? a. It acts as a source of oxygen atom found in the product O2. b. It acts as an electron donor. c. It serves as a reactant. d. It serves as a solvent. e. All of the above

e. All of the above

Which step in glycolysis is an example of substrate-level phosphorylation? a. Step 1: glucose + ATP → glucose 6-phosphate + ADP + Pi b. Step 3: fructose 6-phosphate + ATP → fructose 1,6-bisphosphate + ADP + Pi c. Step 7: 1,3-bisphosphoglycerate + ADP + Pi → 3-phosphoglycerate + ATP d. Step 10: phosphoenolpyruvate + ADP + Pi → pyruvate + ATP e. Both c and d

e. Both c and d

Cellular respiration refers to the metabolic process that a. involves the incomplete breakdown of pyruvate. b. starts with sucrose. c. produces 32 NADH molecules. d. produces less energy than fermentation. e. oxidizes organic molecules to obtain a useful form of energy.

e. oxidizes organic molecules to obtain a useful form of energy.

The mitochondrial electron transport chain a. is the site of most of the reactions of the citric acid cycle. b. synthesizes ATP. c. pumps protons into the mitochondrial matrix during electron transport. d. oxidizes water to ? O2 and 2 H+. e. oxidizes the intermediate electron carriers, NADH and FADH2.

e. oxidizes the intermediate electron carriers, NADH and FADH2.

In photosynthesis, NADPH is used for the a. reduction of O2 to water. b. synthesis of ATP. c. regeneration phase of the Calvin cycle. d. formation of 3-phosphoglycerate (3PG). e. reduction of 3-phosphoglycerate (3PG).

e. reduction of 3-phosphoglycerate (3PG).

All of the following can happen when a photon comes into contact with a pigment molecule except a. the photon gets scattered or reflected from the molecule. b. the photon excites an electron in the molecule. c. the photon gets transmitted through the molecule. d. the photon is absorbed by the molecule. e. the photon lowers the ground state of the molecule.

e. the photon lowers the ground state of the molecule.

A metabolic pathway is a. a series of separate chemical reactions that together accomplish a complex chemical transformation. b. a set of chemical transformational steps, each with a specific enzyme. c. a means for transforming cellular energy. d. vulnerable to inhibitors and activators that target some key enzymes. e. All of the above

e. All of the above

Which statement accurately describes the primary difference between lactic acid fermentation and alcoholic fermentation? a. Lactic acid fermentation produces a three-carbon molecule, and alcoholic fermentation produces a two-carbon molecule. b. Lactic acid fermentation regenerates NAD+, but alcoholic fermentation does not. c. Lactic acid fermentation produces more energy than alcoholic fermentation. d. Lactic acid fermentation produces less energy than alcoholic fermentation. e. Lactic acid fermentation produces a 2-carbon molecule, but alcoholic fermentation does not.

a. Lactic acid fermentation produces a three-carbon molecule, and alcoholic fermentation produces a two-carbon molecule.

Which statement describes ways that coenzymes are involved in cellular respiration and photosynthesis? a. Reduced coenzymes act as carriers of energy released from cellular respiration and as carriers of energy absorbed from light during photosynthesis. b. Oxidized coenzymes act as carriers of energy released from cellular respiration and as carriers of energy absorbed from light during photosynthesis. c. Reduced coenzymes act as carriers of energy released from cellular respiration, and oxidized coenzymes act as carriers of energy absorbed from light during photosynthesis. d. Oxidized coenzymes act as carriers of energy released from cellular respiration, and reduced coenzymes act as carriers of energy absorbed from light during photosynthesis. e. Oxidized and reduced coenzymes link the energy released from cellular respiration to the energy absorbed from light during photosynthesis.

a. Reduced coenzymes act as carriers of energy released from cellular respiration and as carriers of energy absorbed from light during photosynthesis.

Which statement about oxidative phosphorylation is false? a. The process requires a membrane that is permeable to protons. b. During the process, ATP is formed as a result of the transfer of energy from NADH and FADH2 to a proton gradient. c. The process takes place in the mitochondria in eukaryotes and in the cell membrane in prokaryotes. d. The process involves respiratory chain proteins and ATP synthase. e. The process requires the presence of ADP and Pi.

a. The process requires a membrane that is permeable to protons.

During photosynthesis in green plants, water is a. oxidized to O2 in the light. b. reduced to hydrogen gas. c. used to hydrolyze ATP. d. oxidized to O2 in the dark. e. an electron acceptor.

a. oxidized to O2 in the light.

The end products of glycolysis are a. pyruvate, ATP, and NADH. b. pyruvate, ATP, and NAD+. c. acetyl CoA, ATP, and NAD+. d. pyruvate. e. acetyl CoA, ATP, and NADH.

a. pyruvate, ATP, and NADH.

Fermentation a. results in the formation of lactic acid or ethanol. b. completely oxidizes glucose to CO2 and H2O. c. is not coupled to ATP synthesis. d. occurs under aerobic conditions in yeasts. e. is endergonic.

a. results in the formation of lactic acid or ethanol.

In the mitochondrial electron transport chain, cyanide inhibits the enzyme that reduces O2 to water. Which statement is the most accurate with respect to the effects of cyanide on glucose catabolism in muscle cells? a. The citric acid cycle and glycolysis would be inhibited. b. The citric acid cycle would be inhibited, but glycolysis would not. Ethanol would accumulate. c. The citric acid cycle would be inhibited, but glycolysis would not. Lactic acid would accumulate. d. The citric acid cycle and glycolysis would be stimulated. e. The citric acid cycle would not be inhibited, but glycolysis would.

c. The citric acid cycle would be inhibited, but glycolysis would not. Lactic acid would accumulate.

The ultimate source of energy for ATP synthesis in chloroplasts is a. electron transport. b. the electrochemical proton gradient. c. light. d. energized chlorophylls. e. NADPH.

c. light.

Under anaerobic conditions, _______ is absent. a. glucose b. lactate c. oxygen d. carbon dioxide e. pyruvate

c. oxygen

Cyclic electron transport involves _______ and indirectly generates _______. a. photosystem I; NADPH b. photosystem II; NADPH c. photosystem I; ATP d. photosystem II; ATP e. photosystem II; oxygen

c. photosystem I; ATP

ATP synthase is the protein complex that a. is difficult to see under an electron microscope. b. rotates when ATP is hydrolyzed in the mitochondrial matrix. c. rotates when protons flow through it, causing ADP and Pi to combine. d. transfers electrons from the inner mitochondrial space to the mitochondrial matrix. e. creates a proton-motive force when glucose is oxidized.

c. rotates when protons flow through it, causing ADP and Pi to combine.

The hydrolysis of ATP can be summarized by the equation below. ATP + H2O → ADP + Pi ΔG = -7.3 kcal/mol How many moles of ATP will a man hydrolyze in a day if he expends 2,300 kilocalories of free energy through this process? a. 73 mol b. 105 mol c. 315 mol d. 945 mol e. 16,790 mol

c. 315 mol

Which statement about metabolic pathways is false? a. Chemical transformations occur in a series of separate chemical reactions. b. A specific enzyme catalyzes each transformational step. c. In prokaryotes, reactions in a pathway are located in multiple compartments. d. Inhibitors that target some key enzymes in a pathway can slow the rate of reaction. e. Activators that target some key enzymes in a pathway can increase the rate of reaction.

c. In prokaryotes, reactions in a pathway are located in multiple compartments.