Photosynthesis

Plants that fix carbon dioxide into organic acids at night when the stoma are open and carry out the Calvin cycle during the day when the stoma are closed are called
1. C3 plants
2. C4 plants
3. CAM plants
4. only A and B
5. A, B, and C are correct
Photorespiration lowers the efficiency of photosynthesis by removing which of the following from the Calvin cycle?
1. carbon dioxide molecules
2. glyceraldehyde phosphate molecules
3. ATP molecules
4. ribulose bisphosphate molecules
5. RuBP carboxylase molecules
Assume a thylakoid is somehow punctured so that the interior of the thylakoid is no longer separated from the stroma. This damage will have the most direct effect on which of the following processes?
1. the splitting of water
2. the absorption of light energy by chlorophyll
3. the flow of electrons from photosystem II to photosystem I
4. the synthesis of ATP
5. the reduction of NADP⁺
Why are C4 plants able to photosynthesize with no apparent photorespiration?
1. They do no carry out the Calvin cycle.
2. They use a more efficient enzyme to initially fix carbon dioxide.
3. They are adapted to cold, wet climates.
4. They conserve water more efficiently.
5. They exclude oxygen from their tissues.
Why is the absorption spectrum for chlorophyll "a" and the action spectrum for photosynthesis different?
1. Green and yellow wavelengths inhibit the absorption of red and blue wavelengths.
2. Bright sunlight destroys photosynthetic pigments
3. The two lines are probably the result of inaccurate measurements.
4. Other pigments absorb light in addition to chlorophyll "a".
5. Anaerobic bacteria probably interfered with light absorption.
Which of the following statements about the light reactions of photosynthesis is FALSE?
1. The splitting of water molecules provides a source of electrons.
2. Chlorophyll (and other pigments) absorb light energy which excites electrons.
3. An electron transport chain is used to create a proton gradient.
4. The proton gradient is used to reduce NADP.
5. Some electrons are recycled and some are not.
Which of the following are products of the Calvin cycle and are utilized in the light reactions of photosynthesis?
1. Carbon dioxide and glucose
2. Water and oxygen
3. ADP, Pi and NADP⁺
4. electrons and H⁺
5. both C and D are correct
From the photosynthetic action spectrum, we can correctly conclude that
1. chlorophyll absorbs more green than red light.
2. plants can use all colors of visible light for photosynthesis.
3. every color of light is equally good for photosynthesis.
4. light in the green range produces the most efficient photosynthesis.
5. there are tow independent photosystems in leaves: one for red light alone, one for blue light alone.
The primary function of the light reactions of photosynthesis is
1. to produce energy-rich glucose from carbon dioxide and water.
2. to produce ATP and NADPH
3. to produce NADPH used in respiration.
4. to convert light energy to the chemical energy of PGAL
5. to use ATP to make glucose.
The reactions of the Calvin cycle require all of the following molecules EXCEPT
1. carbon dioxide
2. ATP
3. RuBP
4. glucose
5. NADPH
All of the following statements are true EXCEPT:
1. Thylakoid membranes contain the photosynthetic pigments.
2. The oxygen released during photosynthesis come from water.
3. Glyceraldehyde phosphate is produced only in the light reactions of photosynthesis.
4. The light reactions of photosynthesis provide the energy for the Calvin cycle.
5. When chlorophyll is reduced, it gains electrons.
You have just discovered a new flower species that has a unique photosynthetic pigment. The leaves of this plant appear to be reddish yellow. What wavelengths of visible light are NOT being absorbed by this pigment?
1. red and yellow
2. blue and violet
3. green and yellow
4. blue, green and red
5. green, blue and violet
All of the events listed below occur in the energy-capturing light reaction of photosynthesis EXCEPT
1. oxygen is produced.
2. NADP⁺ is reduced to NADPH
3. carbon dioxide is incorporated into PGA
4. ADP is phosphorylated to yield ATP
5. light is absorbed and funneled to a reaction center chlorophyll "a"
The chemiosmotic process in chloroplasts involves the
1. establishment of a proton gradient.
2. diffusion of electrons through the thylakoid membrane.
3. oxidation of water to produce ATP energy.
4. movement of water by osmosis into the thylakoid space from the stroma.
5. reduction of carbon dioxide to glucose by NADPH and ATP
Which of the following enzymes is probably the most abundant protein in the world?
1. PEP carboxylase
2. hexokinase
3. RuBP carboxylase/oxygenase
4. aldolase
5. pyruvate kinase
In C4 photosynthesis, carbon fixation takes place in the _____ cells, and then is transferred as malic or aspartic acid to _____ cells, where carbon dioxide is released for entry into the Calvin cycle.
1. mesophyll; bundle-sheath
2. stomatal; mesophyll
3. bundle-sheath; epidermal
4. epidermal; mesophyll
5. stomatal; epidermal
Because bundle-sheath cells are relatively protected from atmospheric oxygen, the level of ________ is held to a minimum in C4 plants.
1. glycolysis
2. photosynthesis
3. oxidative phosphorylation
4. photorespiration
5. decarboxylation of malic acid
Which of the following statements regarding events in the functioning of photosystem II is false?
1. Light energy excites electrons in an antenna pigment in a photosynthetic unit.
2. The excitation is passed along to a molecule of P680 chlorophyll in the photosynthetic unit.
3. The P680 chlorophyll donates a pair of protons to NADPH, which is thus converted to NADP⁺
4. The electron vacancies in P680 are filled by electrons derived from water.
5. The splitting of water yields molecular oxygen as a by-product.
All of the following compounds are required (i.e. are necessary constituents for chemical reactions) at some stage of photosynthesis in plants, EXCEPT
1. adenosime triphosphate
2. NADP
3. water
4. oxygen
5. carbon dioxide
On which of the following features do most plant and animal cells differ?
1. active transport mechanisms
2. mitochondrial function
3. primary energy source
4. transcription
5. structure of nucleus
Which of the following is NOT TRUE of ribulose bisphosphate carboxylase?
1. It is a protein
2. It speeds up a chemical reaction.
3. It lowers the energy of activation.
4. It catalyzes a phosphorylation reaction.
5. It has an affinity for both oxygen and carbon dioxide.
Where does the Calvin cycle of photosynthesis take place?
1. stroma of the chloroplast
2. thylakoid membrane
3. cytoplasm surrounding the chloroplast
4. chlorophyll molecule
5. outer membrane of the chloroplast
CAM plants can keep stomates closed in daytime, thus reducing loss of water. They can do this because they can
1. fix CO2 into organic acids during the night
2. fix CO2 into sugars in the bundle-sheath cells
3. fix CO2 into pyruvic acid in the mesophyll cells
4. use the enzyme phosphofructokinase, which outcompetes rubisco for CO2
5. use photosystem I and II at night
All of the following statements are correct regarding the Calvin cycle of photosynthesis EXCEPT
1. the energy source utilized is the ATP and NADPH obtained through the light reaction.
2. these reactions begin soon after sundown and end before sunrise.
3. the 5-carbon sugar RuBP is constantly being regenerated.
4. one of the end products is glyceraldehyde phosphate
Of the following, the color of light least effective in driving photosynthesis is
1. blue
2. red
3. orange
4. green
5. yellow
Cyclic electron flow in the chloroplast produces
1. ATP
2. NADPH
3. glucose
4. FADH
5. A and B only
In plant cells, ATP is made in response to light. An electron transport chain is involved. This electron transport chain is found in the
1. thylakoid membranes of chloroplasts.
2. stroma of chloroplast
3. inner membrane of mitochondria
4. matrix of mitochondria
5. cytoplasm
If photosynthesizing green algae are provided with CO2 synthesized with heavy oxygen (isotope), later analysis will show that all but one of the following compounds produced by the algae contain the oxygen isotope.
1. PGA
2. PGAL
3. glucose
4. RuBP
5. Molecular oxygen
The process of noncyclic photophosphorylation uses light energy to synthesize
1. ADP and ATP
2. ATP and P700
3. ATP and NADPH
4. ADP and NADP
5. P700 and P680
If you ran the same experiment without passing light through a prism, what would you predict?
1. There would be no difference in results.
2. The bacteria would be relatively evenly distributed along the algal filaments.
3. The number of bacteria present would decrease due to an increase in the carbon dioxide concentration.
4. The number of bacteria present would increase due to an increase on the carbon dioxide concentration.
5. The number of bacteria would decrease due to a decrease in the temperature of the water.
CAM plants differ from C4 plants in that they
1. incorporate carbon dioxide into organic acids at night
2. incorporate carbon dioxide into a three-carbon compound
3. incorporate carbon dioxide into a four-carbon compound.
4. do not use rubisco as an enzyme
5. use phosphoenolpyruvate acid as a source of carbon dioxide.
Which one of the following statements BEST describes the relationship between photosynthesis and respiration?
1. Respiration is the exact reversal of the biochemical pathways of photosynthesis.
2. Photosynthesis stores energy in complex organic molecules and respiration releases it.
3. Photosynthesis occurs only in plants and respiration occurs only in animals.
4. ATP molecules are produced in photosynthesis and used up in respiration.
5. Respiration is anabolic and photosynthesis is catabolic.
In a plant cell, where is ATP synthase located?
1. thylakoid membrane
2. plasma membrane
3. inner mitochondrial membrane
4. A and C
5. A, B, and C
Synthesis of ATP by the chemiosmotic mechanism occurs during
1. photosynthesis
2. respiration
3. both A and B
4. neither A or B
Oxidation of waters occurs during
1. photosynthesis
2. respiration
3. Both A and B
4. Neither A or B
The reduction of NADP⁺ occurs during
1. Photosynthesis
2. Respiration
3. Both A and B
4. Neither A or B
Carbon dioxide fixation occurs during
1. Photosynthesis
2. Respiration
3. Both A and B
4. Neither A or B
The electron flow along a cytochrome chain occurs during
1. Photosynthesis
2. Respiration
3. Both A and B
4. Neither A or B
Oxidative phosphorylation occurs during
1. Photosynthesis
2. Respiration
3. Both A and B
4. Neither A or B
The generation of proton gradients across membranes occurs during
1. Photosynthesis
2. Respiration
3. Both A and B
4. Neither A or B
Which of the following is NOT a useful function of the light reactions?
1. releasing oxygen for photorespiration
2. splitting water
3. synthesis of NADPH
4. harvesting photons of light
5. converting light energy to chemcial energy
Which of the following is NOT directly associated with photosystem II?
1. splitting water
2. release of oxygen
3. harvesting light energy by chlorophyll
4. photophosphorylation
5. P680
Which of the following is NOT directly associated with photosystem I?
1. harvesting light energy by chlorophyll
2. receiving electrons from plastocyanin
3. P700
4. splitting water
5. passing electrons to ferredoxin
What are the products of the light reactions that are subsequently used by the Calvin cycle?
1. oxygen and carbon dioxide
2. carbon dioxide and RuBP?
3. water and carbon
4. electrons and photons
5. ATP and NADPH
In green plants, the primary function of the Calvin cycle is to
1. use ATP to release carbon dioxide
2. use NADPH to release carbon dioxide
3. split water and release oxygen
4. transport RuBP out of the chloroplast
5. construct simple sugars from carbon dioxide
As a research scientist, you measure the amount of ATP and NADPH consumed by the Calvin cycle in 1 hour. You find 30,000 molecules of ATP consumed, but only 20,000 molecules of NADPH. Where did the extra ATP molecules come from?
1. photosystem II
2. photosystem I
3. cyclic electron flow
4. noncyclic electron flow
5. chlorophyll
You are a research scientist studying photosynthesis. In an experiment performed during the day, you provide a new plant, just discovered in South America, with radioactive carbon-14 dioxide as a metabolic tracer. The carbon-14 is incorporated first into oxaloacetic acid. The plant is best characterized as
1. a C4 plant
2. a C3 plant
3. a CAM plant
4. a heterotroph
5. a chemoautotroph
Which of the following statements best represents the relationships between the light reactions and the Calvin cycle?
1. The light reactions provide ATP and NADPH to the Calvin cycle, and the cycle returns ADP, Pi and NADP⁺ to the light reactions.
2. The light reactions provide ATP and NADPH to the carbon fixation step of the Calvin cycle, and the cycle provides water and electrons to the light reactions.
3. The light reactions supply the Calvin cycle with CO2 to produce sugars, and teh Calvin cycle supplies the light reactions with sugars to produce ATP.
4. The light reactions provide the Calvin cycle with oxygen for electron flow, and the Calvin cycle provides the light reactions with water to split.
5. There is no relationship between the light reactions and the Calvin cycle.
In the thylakoid membranes, what is the main role of the antenna pigment molecules?
1. to split water and release oxygen to the reaction center chlorophyll
2. to harvest photons and transfer light energy to the reaction center chlorophyll
3. to synthesize ATP from ADP and Pi
4. to pass electrons to ferredoxin and then NADPH
5. to concentrate photons inside the stroma
In mitochondria, chemiosmosis translocates protons from the matrix into the intermembrane space whereas in chloroplasts, chemiosmosis translocates protons from
1. the stroma to the chlorophyll
2. the matrix to the stroma
3. the stroma into the thylakoid compartment
4. the intermembrane space to the matrix.
5. the light reactions to the Calvin cycle
Use the following key:

A. light reaction alone
B. the Calvin cycle alone
C. both A and B
D. neither A or B
E. occurs in the chloroplast but is not part of photosynthesis

Which produces molecular oxygen
1. A
2. B
3. C
4. D
5. E
Use the following key:

A. light reaction alone
B. the Calvin cycle alone
C. both A and B
D. neither A or B
E. occurs in the chloroplast but is not part of photosynthesis

Which forms a proton gradient?
1. A
2. B
3. C
4. D
5. E
Use the following key:

A. light reaction alone
B. the Calvin cycle alone
C. both A and B
D. neither A or B
E. occurs in the chloroplast but is not part of photosynthesis

Which requires ATP?
1. A
2. B
3. C
4. D
5. E
Use the following key:

A. light reaction alone
B. the Calvin cycle alone
C. both A and B
D. neither A or B
E. occurs in the chloroplast but is not part of photosynthesis

Which requires ADP?
1. A
2. B
3. C
4. D
5. E
Use the following key:

A. light reaction alone
B. the Calvin cycle alone
C. both A and B
D. neither A or B
E. occurs in the chloroplast but is not part of photosynthesis

Which produces NADH?
1. A
2. B
3. C
4. D
5. E
Use the following key:

A. light reaction alone
B. the Calvin cycle alone
C. both A and B
D. neither A or B
E. occurs in the chloroplast but is not part of photosynthesis

Which produces NADPH?
1. A
2. B
3. C
4. D
5. E
Use the following key:

A. light reaction alone
B. the Calvin cycle alone
C. both A and B
D. neither A or B
E. occurs in the chloroplast but is not part of photosynthesis

Which is inactive in the dark?
1. A
2. B
3. C
4. D
5. E
Use the following key:

A. light reaction alone
B. the Calvin cycle alone
C. both A and B
D. neither A or B
E. occurs in the chloroplast but is not part of photosynthesis

Which requires CO2?
1. A
2. B
3. C
4. D
5. E
Use the following key:

A. light reaction alone
B. the Calvin cycle alone
C. both A and B
D. neither A or B
E. occurs in the chloroplast but is not part of photosynthesis

Which requires glucose?
1. A
2. B
3. C
4. D
5. E
Use the following key:

A. light reaction alone
B. the Calvin cycle alone
C. both A and B
D. neither A or B
E. occurs in the chloroplast but is not part of photosynthesis

Which produces triose sugars?
1. A
2. B
3. C
4. D
5. E
The three substrates (formal reactants) for the enzyme RuBP carboxylase (oxidase rubisco) are
1. CO2, O2 and RuBP
2. CO2, glucose and RuBP
3. RuBP, ATP and NADPH
4. triose-P, glucose and CO2
5. RuBP, CO2 and ATP
Thylakoids stacked in columns
1. do not occur in chloroplasts of C3 plants.
2. have been shown to promote photorespiration.
3. are called grana
4. decrease surface area to reduce damage to chlorophyll by excessive light energy.
5. are called stroma
Which of the following is most clearly associated with a decrease in potential world food production?
1. increased CO2 in the atmosphere
2. CAM photosynthesis
3. C4 photosynthesis
4. photorespiration
5. the abundance of rubisco in nature
Oxidative phosphorylation in mitochondria
1. has been shown to prevent carbon fixation in chloroplasts.
2. is identical to photophosphorylation in chloroplast
3. and photophosphorylation in chloroplasts produce ATP in plants.
4. generates light that drives photophosphorylation in chloroplasts
5. doe not happen in plants because they have chloroplasts by no mitochondria.
Each photosystem
1. contains a mix of chlorophyll and carotenoids.
2. has a light-gathering antenna complex.
3. has special chlorophyll "a" molecule in the reaction center.
4. All three of the above.
5. None of the above.
The reaction center chlorophyll of photosystem I is known as P700 because
1. there are 700 chlorophyll molecules in the center.
2. this pigment is best at absorbing light with a wavelength of 700 nm.
3. there are 700 photosystem I components to each chloroplast.
4. it absorbs 700 photons per minute.