Chapter 10

As a research scientist, you measure the amount of ATP and NADPH consumed by the Calvin cycle in 1 hour. You find that 30,000 molecules of ATP were consumed, but only 20,000 molecules of NADPH were consumed. Where did the extra ATP molecules come from? A) cyclic electron flow B) photosystem II C) chlorophyll D) photosystem I E) linear electron flow

A

How are the light-capturing reactions and the Calvin cycle interdependent on each other? A) The Calvin cycle requires the ATP and NADPH produced in the light-capturing reactions, while the inputs to the light-capturing reactions are regenerated by the Calvin cycle. B) The Calvin cycle accepts the electrons generated by the light-capturing reactions, while the light-capturing reactions regenerate the NADP+ for the Calvin cycle. C) The light-capturing reactions generate the ATP necessary to power the Calvin cycle, while the Calvin cycle generates that NADPH needed for the light-capturing reactions. D) The Calvin cycle generates the CO2 that enters into the light-capturing reactions, while the light-capturing reactions generate the glucose that enters into the Calvin cycle.

A

Photorespiration _____. A) generates carbon dioxide and consumes ATP and oxygen B) consumes carbon dioxide and generates ATP, sugars, and oxygen C) generates ATP and sugars and consumes oxygen and carbon dioxide D) generates oxygen and consumes ATP, carbon dioxide, and sugars

A

Where do the enzymatic reactions of the Calvin cycle take place? A) stroma of the chloroplast B) cytosol around the chloroplast C) thylakoid space D) thylakoid membranes E) matrix of the mitochondria

A

Which of the following molecules is the primary product of photosystem I? A) NADPH B) Oxygen C) Carbon dioxide D) ATP

A

Which process is most directly driven by light energy? A) removal of electrons from chlorophyll molecules B) reduction of NADP+ molecules C) ATP synthesis D) carbon fixation in the stroma E) creation of a pH gradient by pumping protons across the thylakoid membrane

A

A spaceship is designed to support animal life for a multiyear voyage to the outer planets of the solar system. Plants will be grown to provide oxygen and to recycle carbon dioxide. Since the spaceship will be too far from the sun for photosynthesis, an artificial light source will be needed.If the power fails and the lights go dark, CO2 levels will _____. A) fall because plants will cease to respire in the dark B) rise as a result of both animal and plant respiration C) remain balanced because plants will continue to fix CO2 in the dark D) rise as a result of animal but not plant respiration E) fall because plants will increase CO2 fixation

B

Assume a thylakoid is somehow punctured so that the interior of the thylakoid is no longer separated from the stroma. This damage will most directly affect the _____. A) absorption of light energy by chlorophyll B) synthesis of ATP C) reduction of NADP+ D) flow of electrons from photosystem II to photosystem I E) splitting of water

B

The antenna complex in a photosystem: A) generates NADPH. B) captures photons from sunlight. C) transfers excited electrons to the primary electron acceptor. D) pumps protons into the thylakoid lumen. E) generates ATP.

B

What is the importance of the light-independent reactions in terms of carbon flow in the biosphere? A) The light-independent reactions turn sugar into ATP for energy. B) The light-independent reactions turn CO2, a gas, into usable carbon in the form of sugars. C) The light-independent reactions use CO2 to make ATP. D) The light-independent reactions turn glucose, a sugar, into CO2 gas.

B

Which molecule is regenerated in the regeneration phase of the Calvin cycle? Without regeneration of this molecule, the Calvin cycle would stop. A) 3-phosphoglycerate B) RuBP C) ATP D) G3P

B

Which of the following statements best describes the relationship between the light-dependent and light-independent reactions of photosynthesis? A) The light-dependent reactions pass electrons through an electron transport chain to the light-independent reactions. B) The light-dependent reactions produce ATP and NADPH, which are then used by the light-independent reactions. C) The light-independent reactions release energy, and the light-dependent reactions require energy. D) The light-dependent reactions produce carbon dioxide, which is then used by the light-independent reactions.

B

Which process produces oxygen? A) Cellular Respiration B) Photosynthesis

B

Which set of reactions uses H2O and produces O2? A) light independent reactions B) light dependent reactions

B

Which of the following correctly identify a role of the NADPH produced in the light-capturing reactions? Select all that apply. A) It is used to regenerate RuBP from G3P molecules. B) It is used to produce G3P molecules. C) It is used by rubisco to fix CO2 to RuBP. D) It is used to reduce CO2 to carbohydrates.

B,D

An investigator exposes chloroplasts to 700-nm photons and observes low O2O2 production, but high ATPATP production. Which of the following best explains this observation? A) The O2 is being converted to water as a terminal electron acceptor in the production of ATP. B) The electrons from water are directly transferred to NADP+, which is used to generate ATP. C) Photosystem II is not splitting water, and the ATP is being produced by cycling electrons via photosystem I. D) Electron transport has stopped and ATP is being produced by the Calvin cycle.

C

Fossil fuel consists of coal, oil, and natural gas that have been formed from the remains of plants and animals that died millions of years ago. What was the source of the energy used to produce the high-energy molecules in these fossil fuels? A) Glucose B) ATP C) Sunlight D) Fatty acids

C

In its mechanism, photophosphorylation is most similar to ________. A) substrate-level phosphorylation in glycolysis B) carbon fixation C) oxidative phosphorylation in cellular respiration D) reduction of NADP+ E) the Calvin cycle

C

When oxygen is released as a result of photosynthesis, it is a direct by-product of _____. A) the electron transfer system of photosystem II B) reducing NADP+ C) splitting water molecules D) chemiosmosis E) the electron transfer system of photosystem I

C

As electrons are passed through the system of electron carriers associated with photosystem II, they lose energy. What happens to this energy? A) It is used to phosphorylate NAD+ to NADPH, the molecule that accepts electrons from photosystem I. B) It excites electrons of the reaction center of photosystem I. C) It is lost as heat. D) It is used to establish and maintain a proton gradient.

D

At what point in photosynthesis is the electromagnetic energy of light first converted into chemical energy? A) The conversion first occurs when the photosystem II complex enzymes remove electrons from water, leaving protons and oxygen. B) The conversion first occurs when protons are transferred from the stroma to the lumen side of the thylakoid membrane. C) The conversion first occurs when the proton-motive force drives the production of ATP. D) The conversion first occurs when electrons are transferred from excited pigments to an electron carrier in a photosystem.

D

Reactions that require CO2 take place in _____. A) the light reactions alone B) the chloroplast, but not as part of photosynthesis C) neither the light reactions nor the Calvin cycle D) the Calvin cycle alone E) both the light reactions and the Calvin cycle

D

The enzyme that catalyzes the fixation of carbon dioxide in photosynthesis is _____. A) chlorophyll B) carbon dioxidase C) ATP synthase D) rubisco

D

The noncyclic electron flow of photosystem II and I splits water to donate electrons and produce a proton gradient (motive force). The electrons are accepted by NAD+ to make NADPH. The proton gradient is used to make ______ through the _______. A) water; oxygen B) ATP; carbon dioxide C) NADH; oxygen D) ATP; ATP synthase

D

What molecule is split in the oxygen-releasing light reactions of photosynthesis? A) Chlorophyll B) Carbon dioxide C) NADPH D) Water

D

Which of the following correctly identify a role of the ATP produced in the light-capturing reactions? A) It serves the same role as ATP produced by mitochondria. B) It is used to breakdown G3P molecules C) It is used by rubisco to fix CO2 to RuBP. D) It is used to regenerate RuBP from G3P molecules.

D

Which of the following statements best describes the relationship between photosynthesis and respiration? A) ATP molecules are produced in photosynthesis but not in aerobic respiration. B) Photosynthesis occurs only in plants; respiration occurs only in animals. C) Photosynthesis is catabolic; respiration is anabolic. D) Photosynthesis stores energy in complex organic molecules; respiration releases energy from complex organic molecules E) Respiration runs the biochemical pathways of photosynthesis in reverse.

D

Some photosynthetic organisms contain chloroplasts that lack photosystem II, yet they are able to survive. The best way to detect the lack of photosystem II in these organisms would be to ________. A) determine if they have thylakoids in the chloroplasts B) do experiments to generate an action spectrum C) test for production of either sucrose or starch D) test for CO2 fixation in the dark E) test for liberation of O2 in the light

E