CHAPTER 8: PHOTOSYNTHESIS questions

In photosynthesis, the reduction of 3-phosphoglycerate to form carbohydrate requires: A) ATP and NADPH. B) ATP. C) RuBP. D) NADPH. E) rubisco.

A) ATP and NADPH.

A plant cell is exposed to a toxin that makes the thylakoid membrane freely permeable to protons. As a result of adding this toxin, the amount of NADPH in the chloroplast would most likely: A) Increase B) Decrease C) Stay the same

A) Increase

The concentration of ADP in a cell is increasing. Assuming that the cell has plenty of glucose and oxygen available, phosphofructokinase (PFK) activity should: A) Increase B) Decrease C) Stay the same

A) Increase

The coronary arteries supply blood to the heart muscle. Which of the following events would occur in heart tissue following a heart attack due to a block in the coronary arteries? (Select all that apply.) A) The production of ATP would decrease. B) The production of water would increase. C) Lactic acid would accumulate in the tissue due to glycolysis and fermentation. D) Phosphofructokinase, an intermediary enzyme of glycolysis, would be activated.

A) The production of ATP would decrease. C) Lactic acid would accumulate in the tissue due to glycolysis and fermentation. D) Phosphofructokinase, an intermediary enzyme of glycolysis, would be activated.

A new experimental pesticide is being tested by a large agricultural chemical company. An unfortunate side effect in plants treated with this new product is a decrease in NADPH production in the chloroplasts. (Interestingly, reduction of NAD+ to NADH in the mitochondria is unaffected.) Given this observation, which of the following would you expect to observe in the chloroplasts of these plants? A) an increase in 3-phosphoglycerate levels and a decrease in RuBP production B) an increase in 3-phosphoglycerate production and an increase in RuBP production C) an increase in glyceraldehyde-3-phosphate production D) a decrease in 3-phosphoglycerate levels and an increase in RuBP production

A) an increase in 3-phosphoglycerate levels and a decrease in RuBP production

A new experimental pesticide is being tested by a large agricultural chemical company. An unfortunate side effect in plants treated with this new product is the partial inhibition of ferredoxin-NADP+ reductase. Given this observation, which of the following would you expect to observe in the photosynthetic cells of these plants? A) decreased rate of triose phosphate production B) decreased levels of NADP+ in the chloroplast C) decreased levels of ATP in the chloroplast

A) decreased rate of triose phosphate production

Where are the chlorophyll molecules located in plant cells that carry out photosynthesis? A) in the thylakoid membranes B) in the lumen of the thylakoids in the chloroplasts C) in the plasma membrane D) in the cytoplasm E) in the stroma of the chloroplasts

A) in the thylakoid membranes

How do antenna chlorophylls differ from reaction center chlorophylls?

Antenna chlorophyll molecules transfer absorbed energy from one antenna chlorophyll molecule to another, and ultimately to the reaction center. Reaction center chlorophylls transfer electrons to an electron acceptor, resulting in the oxidation of reaction center chlorophyll molecules.

The concentration of ADP in a cell is increasing. Assuming that the cell has plenty of glucose and oxygen available, fatty acid synthesis should: A) Increase B) Decrease C) Stay the same

B) Decrease

When oxygen is depleted, the citric acid cycle stops. Which of the following would you need to add to the system to restore activity? (Select all that apply.) A) acetyl-CoA B) FAD C) NADH D) glucose E) NAD+

B) FAD E) NAD+

Which of the following CORRECTLY describes the role of rubisco in the Calvin cycle? A) Rubisco uses ATP to regenerate RUBP. B) Rubisco incorporates CO2 from the atmosphere into an organic molecule. C) None of the other answer options is correct. D) Rubisco uses NADPH to reduce 3-phosphoglycerate to a three-carbon sugar.

B) Rubisco incorporates CO2 from the atmosphere into an organic molecule

Antinomycin A is a poison that affects the electron transport chain and renders it nonfunctional. In the presence of Antinomycin the Citric Acid Cycle would: A) Speed up B) Slow down C) Remain the same

B) Slow down

Which of the following is TRUE concerning the Calvin cycle and light-harvesting reactions of photosynthesis? A) They take place in different organelles. B) They take place in different compartments of the same organelle. C) They take place in different types of cells in the plant. D) None of the other answer options is correct.

B) They take place in different compartments of the same organelle.

Kangaroo rats live in the desert of the southwestern United States. They have many adaptations to minimize water loss. They obtain a small amount of water from seeds that they eat. However, the rest of the water they obtain is from cellular respiration. A) This could be true, as water is produced in glycolysis. B) This could be true, as water is produced in cellular respiration. C) This could be true, as water is produced in the citric acid cycle. D) This cannot be true, as cellular respiration doesn't really "produce" water. E) This cannot be true, as water is actually consumed in cellular respiration.

B) This could be true, as water is produced in cellular respiration.

Which of the following does NOT happen in the Calvin cycle of photosynthesis? A) the incorporation of CO2 into an organic molecule by RUBISCO B) reduction of NADP+ to NADPH C) hydrolysis of ATP to ADP D) the synthesis of a three-carbon carbohydrate

B) reduction of NADP+ to NADPH

Chloroplast ATP synthases are powered by the flow of protons from the: a) thylakoid lumen to the intermembrane space. B) thylakoid lumen to the stroma. C) stroma to the thylakoid lumen. D)intermembrane space to the cytoplasm. E) stroma to the intermembrane space.

B) thylakoid lumen to the stroma.

The concentration of ADP in a cell is increasing. Assuming that the cell has plenty of glucose and oxygen available, carbon dioxide (CO2) production by the cell should: A) Decrease B) Stay the same C) Increase

C) Increase

As electrons flow from one photosystem to another, the amount of energy present in the electrons decreases. How does the plant cell use the energy lost by the electrons? A) The energy is used directly by ATP synthase to make ATP. B) The energy is used to reduce NADP+ to NADPH. C) The energy is used to create and maintain a proton gradient. D) The energy is used to increase the pH of the thylakoid lumen.

C) The energy is used to create and maintain a proton gradient.

Chlorophyll molecules in chloroplasts normally only fluoresce a very small amount compared to chlorophyll that has been extracted into a solvent solution. Which of the following is the best explanation for this difference? Choice A., In chloroplasts, the molecules are held close together and oriented to allow transfer of excitation energy between molecules. Choice B., In chloroplasts, the molecules are embedded in proteins that block re-emission by fluorescence. Choice C., In chloroplasts, the surrounding solvent is water rather than the organic solvents used to extract chlorophyll into solution.

Choice A., In chloroplasts, the molecules are held close together and oriented to allow transfer of excitation energy between molecules.

When chlorophyll in solution returns to its ground state via energy release, it is ready to absorb another photon. How is this different in the reaction center chlorophyll in the chloroplast? Choice A., The reaction center chlorophyll must obtain a replacement electron Choice B., The reaction center chlorophyll must wait or it becomes damaged. Choice C., The reaction center chlorophyll has a slow recovery rate. Choice D., The reaction center chlorophyll must wait for the antenna to pass the excitation energy.

Choice A., The reaction center chlorophyll must obtain a replacement electron

Which component pictured above does not participate in the flow of electrons? Choice A., Pc Choice B., Fd Choice C., ATP synthase Choice D., light; Pc Choice E., NADP+ reductase

Choice C., ATP synthase

The electron donor that replenishes the PS II reaction center is ______ and for the PS I reaction center is _______. Choice A., Pq; Fd Choice B., H2O; Pc Choice C., H2O; Cyt Choice D., light; Pc Choice E., Pc; Pq

Choice C., H2O; Cyt

When light is absorbed by chlorophyll in solution, it _________BLANK releases the energy in the form of ____________BLANK. Choice A., slowly; heat and light Choice B., slowly; heat Choice C., rapidly; heat and light Choice D., rapidly; heat Choice E., rapidly; light

Choice C., rapidly; heat and light

The photosynthetic reaction center becomes ________ when it passes its __________ to the ______________, which is thus ___________. Choice A., de-energized; photon; acceptor; excited Choice B., oxidized; energy; electron transporter; excited Choice C., reduced; excited electron; electron acceptor; oxidized Choice D., oxidized; excited electron; electron acceptor; reduced

Choice D., oxidized; excited electron; electron acceptor; reduced

Carbon enters the Calvin cycle in the form of: A) triose phosphates. B) RuBP. C) glucose. D) CO2. E) 3-PGA.

D) CO2.

In plants and algae, _____ is the source of the electrons needed for photosynthesis. A) H+ B) CO2 C) NADPH D) H2O E) O2

D) H2O

In the light-dependent reactions of photosynthesis, light energy is captured and stored as potential energy. In which of the following is this energy stored in the light-dependent reactions? A) an electrochemical gradient B) NADPH, ATP, and carbohydrate molecules C) NADPH and ATP D) NADPH, ATP, and an electrochemical gradient E) carbohydrate molecules

D) NADPH, ATP, and an electrochemical gradient

In plants and algae, which of the following is a by-product of photosynthesis? A) H+ B) carbohydrates C) C6H12O6 D) O2 E) CO2

D) O2

During photosynthesis, _____ is reduced to _____. A) oxygen; water B) sugar; oxygen C) water; carbon dioxide D) carbon dioxide; oxygen E) carbon dioxide; sugar

D) carbon dioxide; oxygen

In a thylakoid membrane, absorbed light energy is passed from one chlorophyll molecule to another until it is: A) All these choices are correct. B) released as fluorescence. C) dissipated as heat. D) passed to a reaction center. E) both dissipated as heat and released as fluorescence.

D) passed to a reaction center.

Which step of the Calvin cycle would be affected first by a lack of NADPH? A) carboxylation B) All of these choices are correct. C) regeneration D) reduction

D) reduction

The fluid-filled interior compartment of the thylakoid network is referred to as the: A) cytoplasm. B) intermembrane space. C) grana. D) stroma. E) lumen.

E) lumen.

Which of the following could be TRUE if a plant cell is exposed to a toxin that makes the thylakoid membrane freely permeable to protons? (Select all that apply.) A) The amount of NADPH in the chloroplast would increase. B) There would be no ATP produced in the chloroplasts to power photosynthesis in the absence of light energy. C) The amount of carbohydrate produced would increase. D) ATP generated by the mitochondria would be used to power photosynthesis, so plant cells would not have enough ATP left to supply the many other processes that require it. E) There would be no ATP needed to split water molecules early in the light-dependent pathway. F) There would be no ATP available to drive carbohydrate synthesis in the Calvin cycle.

F) There would be no ATP available to drive carbohydrate synthesis in the Calvin cycle A) The amount of NADPH in the chloroplast would increase..

Assume that PSII has lost the ability to split water. Determine whether each of the following statements will be true or false based on this scenario. ATP synthase will catalyze its reaction more quickly. True False

False

Assume that PSII has lost the ability to split water. Determine whether each of the following statements will be true or false based on this scenario. The Calvin Cycle will proceed normally. True False

False

Assume the redox potential of cyt-b were to change from +70 to -120. Determine whether each of the following statements is true or false for this scenario. NAD+ would accumulate: True False

False

The Calvin cycle requires both ATP and NADPH. Which of these molecules provides the major input of energy needed to synthesize carbohydrates?

NADH

Why are two photosystems needed if H2O is used as an electron donor?

One photosystem is needed to pull electrons from water, and a second photosystem is needed to raise the energy of these electrons enough that they can reduce NADP+.

Calvin cycle

The process in which carbon dioxide is reduced to synthesize carbohydrates, with ATP and NADPH as the energy sources. location: stroma needed: 2 NADH and 3 ATP

Assume that PSII has lost the ability to split water. Determine whether each of the following statements will be true or false based on this scenario. NADP+ will accumulate in the chloroplast. True False

True

Assume that PSII has lost the ability to split water. Determine whether each of the following statements will be true or false based on this scenario. The accessory pigments in PSII will stop transferring energy to each other. True False

True

FeS1 would accumulate in its reduced state: True False

True

If you want to produce carbohydrates containing the heavy oxygen (18O) isotope, should you water your plants with H218O or inject C18O2 into the air?

ou should label the oxygen in CO2 (that is, inject C18O2) because the entire CO2 molecule is used in synthesizing carbohydrates, whereas H2O donates only the electron needed for the reduction step of the Calvin cycle. The extraction of electrons from water releases O2 as a by-product.