Question 1

The electrons of photosystem II are excited and transferred to electron carriers. From which molecule or structure do the photosystem II replacement electrons come?

Accepted Answer

A)   the electron carrier, plastocyanin
B)   photosystem I
C)   oxygen
D)   waterE) None of the above
F) A) and C)

Question 2

Purple photosynthetic bacteria do not contain chloroplasts. They have an antenna system that includes two light- harvesting protein complexes, both of which are integral membrane proteins. The bacteriochlorophyll a molecules contain Mg2+ and absorb light at 800 nm. Which of the following statements comparing photosynthesis in purple bacteria and plant chloroplasts is true?

Accepted Answer

A)   Because purple bacteria do not have chloroplasts, there is no electron transport associated with photosynthesis.
B)   Plant chlorophyll a absorbs in the visible light range, whereas purple photosynthetic bacteriochlorophyll a absorbs light at a longer wavelength.
C)   Bacteriochlorophyll a absorbs light most efficiently in the ultraviolet range, at a significantly shorter wavelength than that for chlorophyll a of chloroplasts.
D)   Bacteriochlorophyll a is a molecule containing Mg2+, whereas chlorophyll a from chloroplasts contains Fe2+.E) A) and B)
F) A) and D)

Question 3

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

Accepted Answer

A)   splitting of water.
B)   reduction of NADP+.
C)   synthesis of ATP.
D)   absorption of light energy by chlorophyll.
E)   flow of electrons from photosystem II to photosystem I.F) D) and E)
G) A) and E)

Question 4

Early investigators thought the oxygen produced by photosynthetic plants came from carbon dioxide. In fact, it comes from

Accepted Answer

A)   H2S.
B)   glucose.
C)   water.
D)   electrons from NADPH.E) B) and D)
F) A) and C)

Question 5

What is a difference between chlorophyll a and chlorophyll b?

Accepted Answer

A)   Chlorophyll a is a pigment, and chlorophyll b is the enzyme that transfers excited electrons from chlorophyll a to electron carriers of the thylakoid membrane.
B)   Chlorophyll a and b absorb light energy at slightly different wavelengths.
C)   Chlorophyll a absorbs yellow light, and chlorophyll b absorbs green.
D)   Chlorophyll a contains Mg++ in a ring structure, whereas chlorophyll b contains iron.E) A) and D)
F) C) and D)

Question 6

Which of the following procedures would identify the enzyme that catalyzes the carboxylation of ribulose- 1,5- bisphosphate?

Accepted Answer

A)   differential sedimentation of a protein extract
B)   introducing radiolabeled carbon dioxide into a plant extract and determining which molecules become radiolabeled
C)   irradiating a leaf extract with red light
D)   purifying a variety of proteins from plant extracts and testing each protein individually to see if it can carboxylate ribulose- 1,5- bisphosphateE) None of the above
F) A) and D)

Question 7

In autumn, the leaves of deciduous trees change colours. This is because the chlorophyll is degraded, and

Accepted Answer

A)   the carotenoids and other pigments are still present in the leaves.
B)   water supply to the leaves has been reduced.
C)   degraded chlorophyll becomes a pigment with different colours.
D)   the cells of the leaves begin to die.E) B) and C)
F) A) and D)

Question 8

In photosynthesis, what is the role of water H2O) ?

Accepted Answer

A)   It accepts electrons liberated from the reaction centre of photosystem I.
B)   It provides O2, the terminal electron acceptor for the electron transport chain.
C)   It allows cyclic photophosphorylation to occur when ATP levels are low in the stroma.
D)   It donates electrons to replace lost electrons in the reaction centre of photosystem II.
E)   It provides the necessary H+ ions needed to reduce glyceraldehyde- 3- phosphate G3P) .F) A) and B)
G) A) and C)

Question 9

Stomata, openings in the leaf, are important to photosynthesis for

Accepted Answer

A)   entry of oxygen that is used in the Calvin cycle.
B)   removal of water and carbon dioxide, the end- products of photo- oxidation.
C)   entry of carbon dioxide that is used in the Calvin cycle.
D)   removal of nitrogen- containing waste products.E) C) and D)
F) A) and B)

Question 10

Some photosynthetic organisms contain chloroplasts that lack photosystem II yet are able to survive. The best way to detect the lack of photosystem II in these organisms would be to

Accepted Answer

A)   test for CO2 fixation in the dark.
B)   determine whether they have thylakoids in the chloroplasts.
C)   do experiments to generate an action spectrum.
D)   test for liberation of O2 in the light.
E)   test for production of either sucrose or starch.F) A) and D)
G) C) and D)

Question 11

The process of photosynthesis probably originated

Accepted Answer

A)   in plants.
B)   three separate times.
C)   in fungi.
D)   in prokaryotes.E) C) and D)
F) B) and C)

Question 12

If pigments from a particular species of plant are extracted and subjected to paper chromatography, which of the following is the most believable result?

Accepted Answer

A)   The single band of pigment that is isolated is always some shade of green.
B)   Paper chromatography would separate the pigments from a particular plant into several bands.
C)   Paper chromatography isolates only the pigments that reflect green light.
D)   Paper chromatography for the plant would isolate a single band of pigment that is characteristic of the particular plant.E) None of the above
F) A) and B)

Question 13

Plastoquinone PQ) , an electron carrier of small molecular weight, is found in the electron transport chain associated with photosystem II. If PQ is not directly anchored to other membrane or cytoplasmic structures, it is probably

Accepted Answer

A)   mobile in the thylakoid membrane.
B)   lipid soluble.
C)   a molecule that serves as a shuttle between the electron transport chain and ATP synthase.
D)   both A and B.E) B) and C)
F) None of the above

Question 14

Energy from sunlight can excite electrons, kicking them out of their orbitals and creating free radicals. Free radicals are highly reactive atoms or molecules that have unpaired electrons. They degrade and destroy other compounds in their vicinity. Carotenoids, one of the pigments present in most chloroplasts, can stabilize these free radicals. This suggests that

Accepted Answer

A)   carotenoids probably have a protective function in the cell.
B)   once chloroplasts are destroyed, the free radicals will destroy the cell.
C)   other pigments besides carotenoids and chlorophyll)  are essential for the health of a plant cell.
D)   carotenoids communicate directly with the immune system of plants.E) All of the above
F) A) and B)

Question 15

Most of the enzymes of the Calvin cycle also function in other metabolic pathways. This should not be a surprising finding, because

Accepted Answer

A)   the Calvin cycle probably evolved at the same time as did glycolysis.
B)   the Calvin cycle is nearly ubiquitous in cells, as are metabolic pathways.
C)   metabolic reactions are catalyzed by enzymes that have multiple functions.
D)   there is a close relationship between carbohydrate synthesis and metabolic breakdown.E) B) and C)
F) A) and D)

Question 16

The light- independent reactions of plants function to make organic molecules using carbon dioxide as a carbon source. What is the electron source that helps reduce carbon dioxide to sugars and other organic molecules?

Accepted Answer

A)   electrons from oxygen
B)   ATP
C)   NADPH
D)   NADHE) C) and D)
F) B) and C)

Question 17

Which of the following statements best describes the relationship between photosynthesis and respiration?

Accepted Answer

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

Question 18

Besides proteins, thylakoid membranes must contain a large number of___________ molecules in the reaction centers in order to harvest light energy.

Accepted Answer

A)   pigment
B)   electron carrier
C)   oligosaccharide
D)   phospholipidE) A) and C)
F) None of the above

Question 19

Photorespiration is

Accepted Answer

A)   not a problem, because oxygen is not available in the chloroplast where photorespiration takes place.
B)   a process involving the carboxylation of ribulose- 1,5- bisphosphate.
C)   a process involving addition of oxygen to ribulose- 1,5- bisphosphate and the formation of ribose- 1,5- diphosphate.
D)   a process involving the addition of oxygen to ribulose- 1,5- bisphosphate and the formation of the products 3- phosphoglycerate and 2- phosphoglycolate.E) A) and B)
F) A) and C)

Question 20

Data suggest that rubisco ribulose- 1,5- bisphosphate carboxylase)  makes up 10% of the total protein found in spinach leaves. Research elucidating the structure of rubisco shows that it has four active sites. Why, with four active sites, might there be such a large concentration of rubisco in plant matter?

Accepted Answer

A)   Rubisco is a very slow enzyme; what it lacks in speed, it makes up in numbers.
B)   Rubisco catalyzes four of the six reactions found in the Calvin cycle.
C)   Three of the four active sites bind carbon dioxide; only one binds ribulose- 1,5- bisphosphate.
D)   All heterotrophic organisms depend on plants, either directly or indirectly, for their food supply.E) B) and C)
F) C) and D)

Exam 10: Photosynthesis

Some photosynthetic organisms contain chloroplasts that lack photosystem II yet are able to survive. The best way to detect the lack of photosystem II in these organisms would be to

Correct Answer
verified

Photorespiration is

Correct Answer
verified

In photosynthesis, what is the role of water H₂O) ?

Correct Answer
verified

Which of the following procedures would identify the enzyme that catalyzes the carboxylation of ribulose- 1,5- bisphosphate?

Correct Answer
verified

In autumn, the leaves of deciduous trees change colours. This is because the chlorophyll is degraded, and

Correct Answer
verified

Plastoquinone PQ) , an electron carrier of small molecular weight, is found in the electron transport chain associated with photosystem II. If PQ is not directly anchored to other membrane or cytoplasmic structures, it is probably

Correct Answer
verified

The light- independent reactions of plants function to make organic molecules using carbon dioxide as a carbon source. What is the electron source that helps reduce carbon dioxide to sugars and other organic molecules?

Correct Answer
verified

Correct Answer
verified

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

Correct Answer
verified

Most of the enzymes of the Calvin cycle also function in other metabolic pathways. This should not be a surprising finding, because

Correct Answer
verified

Which of the following statements best describes the relationship between photosynthesis and respiration?

Correct Answer
verified

Correct Answer
verified

The electrons of photosystem II are excited and transferred to electron carriers. From which molecule or structure do the photosystem II replacement electrons come?

Correct Answer
verified

If pigments from a particular species of plant are extracted and subjected to paper chromatography, which of the following is the most believable result?

Correct Answer
verified

Early investigators thought the oxygen produced by photosynthetic plants came from carbon dioxide. In fact, it comes from

Correct Answer
verified

Correct Answer
verified

What is a difference between chlorophyll a and chlorophyll b?

Correct Answer
verified

The process of photosynthesis probably originated

Correct Answer
verified

Besides proteins, thylakoid membranes must contain a large number of___________ molecules in the reaction centers in order to harvest light energy.

Correct Answer
verified

Stomata, openings in the leaf, are important to photosynthesis for

Correct Answer
verified

Exam 10: Photosynthesis

Some photosynthetic organisms contain chloroplasts that lack photosystem II yet are able to survive. The best way to detect the lack of photosystem II in these organisms would be to

Correct AnswerverifiedShow Answer

Photorespiration is

Correct AnswerverifiedShow Answer

In photosynthesis, what is the role of water H2O) ?

Correct AnswerverifiedShow Answer

Which of the following procedures would identify the enzyme that catalyzes the carboxylation of ribulose- 1,5- bisphosphate?

Correct AnswerverifiedShow Answer

In autumn, the leaves of deciduous trees change colours. This is because the chlorophyll is degraded, and

Correct AnswerverifiedShow Answer

Plastoquinone PQ) , an electron carrier of small molecular weight, is found in the electron transport chain associated with photosystem II. If PQ is not directly anchored to other membrane or cytoplasmic structures, it is probably

Correct AnswerverifiedShow Answer

The light- independent reactions of plants function to make organic molecules using carbon dioxide as a carbon source. What is the electron source that helps reduce carbon dioxide to sugars and other organic molecules?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Most of the enzymes of the Calvin cycle also function in other metabolic pathways. This should not be a surprising finding, because

Correct AnswerverifiedShow Answer

Which of the following statements best describes the relationship between photosynthesis and respiration?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

The electrons of photosystem II are excited and transferred to electron carriers. From which molecule or structure do the photosystem II replacement electrons come?

Correct AnswerverifiedShow Answer

If pigments from a particular species of plant are extracted and subjected to paper chromatography, which of the following is the most believable result?

Correct AnswerverifiedShow Answer

Early investigators thought the oxygen produced by photosynthetic plants came from carbon dioxide. In fact, it comes from

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

What is a difference between chlorophyll a and chlorophyll b?

Correct AnswerverifiedShow Answer

The process of photosynthesis probably originated

Correct AnswerverifiedShow Answer

Besides proteins, thylakoid membranes must contain a large number of___________ molecules in the reaction centers in order to harvest light energy.

Correct AnswerverifiedShow Answer

Stomata, openings in the leaf, are important to photosynthesis for

Correct AnswerverifiedShow Answer

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In photosynthesis, what is the role of water H₂O) ?

Correct Answer
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