Deck 16: Photosynthesis

Question 1

What organelle is responsible for photosynthesis?

A) Golgi apparatus
B) chloroplast
C) endoplasmic reticulum
D) peroxisome
E) glyoxysome

Answer 1

chloroplast

Question 2

What part of the chloroplast is the site of the energy-transducing reactions of photosynthesis?

A) chloroplast outer membrane
B) chloroplast inner membrane
C) stroma
D) thylakoid lumen
E) thylakoid membrane

Answer 2

thylakoid membrane

Question 3

Chlorophylls and carotenoids absorb most light between ______ nm and _____ nm while reflecting most light between _____ nm.

A) 400-500; 600-700; 500-600
B) 300-400; 600-700; 400-600
C) 400-600; 700-800; 600-700
D) 300-400; 700-800; 400-700
E) none of the above

Answer 3

400-500; 600-700; 500-600

Question 4

What is an assembly of antenna pigments?

A) thylakoid
B) granum
C) light-harvesting complex
D) reaction center
E) lamella

Question 5

Which of the following explains how a reaction center is excited?

A) a reaction center can only be excited by direct absorption of a photon of light
B) excitation can occur by any of the antenna pigments in direct contact with the reaction center
C) excitation occurs when an antenna fluoresces so that the photon of light can be captured by a reaction center
D) any antenna of the light harvesting complex can transfer an electron to the reaction center by exciton transfer
E) transfer of heat energy from antenna to reaction center allows for excitation

Question 6

The P680 of photosystem II is composed of _____.

A) two chlorophylls
B) two carotenoids
C) one chlorophyll and one phycocyanin
D) one chlorophyll and one carotenoid
E) one carotenoid and one phycocyanin

Question 7

Since the reduction potential of oxygen is +0.815 V and the reaction catalyzed by P680 is highly exergonic, which of the following is most likely the reduction potential of P680*?

A) -1.15 V
B) -0.815 V
C) +0.77 V
D) +0.83 V
E) +1.15 V

Question 8

Why is photosystem I unable to oxidize water?

A) it cannot transfer protons to the stroma
B) it contains proteins that prevent oxygen from binding to it
C) its reduction potential is exactly equal to that of oxygen
D) it is a very good reducing agent
E) it is not a strong enough oxidizing agent

Question 9

Which of the following shows the correct movement of electrons in the Z-scheme of photosynthesis?

A) H₂O $\rarr$ P700 $\rarr$ plastoquinone $\rarr$ cytochrome b₆f $\rarr$ plastocyanin $\rarr$ P680 $\rarr$ ferredoxin $\rarr$ NADP⁺
B) H₂O $\rarr$ P680 $\rarr$ plastocyanin $\rarr$ cytochrome b₆f $\rarr$ plastoquinone $\rarr$ P700 $\rarr$ ferredoxin $\rarr$ NADP⁺
C) H₂O $\rarr$ P680 $\rarr$ plastoquinone $\rarr$ ferredoxin $\rarr$ plastocyanin $\rarr$ P700 $\rarr$ cytochrome b₆f $\rarr$ NADP⁺
D) H₂O $\rarr$ P680 $\rarr$ plastoquinone $\rarr$ cytochrome b₆f $\rarr$ plastocyanin $\rarr$ P700 $\rarr$ ferredoxin $\rarr$ NADP⁺
E) H₂O $\rarr$ P680 $\rarr$ ferredoxin $\rarr$ plastoquinone $\rarr$ P700 $\rarr$ cytochrome b₆f $\rarr$ plastocyanin $\rarr$ NADP⁺

Question 10

Which of the following occurs during cyclic electron flow?

A) photosystem I absorbs light but not photosystem II
B) protons are pumped into the lumen by cytochrome b₆f
C) electrons are transferred from photosystem I $\rarr$ ferredoxin $\rarr$ cytochrome b₆f $\rarr$ plastocyanin, then back to photosystem I
D) there is no production of NADPH or oxygen
E) all of the above

Question 11

For each molecule of oxygen generated, _____ photons are absorbed by photosystems I and II, _____ protons are transferred from stroma to lumen allowing for the production of _____ molecules of ATP.

A) 4; 8; 2
B) 4; 12; 4
C) 8; 8; 4
D) 8; 12; 3
E) 8; 16; 4

Question 12

The carbon fixing reactions occur in the _____ .

A) thylakoid lumen
B) thylakoid membrane
C) stroma
D) space between inner and outer chloroplast membrane
E) cytosol

Question 13

Which of the following describes photorespiration?

A) consumes ATP
B) consumes NADPH
C) produces CO₂
D) consumes oxygen
E) all of the above

Question 14

The products of the light reactions, ATP and NADPH, are used by ______ and ______, respectively.

A) rubisco; glyceraldehyde-3-phosphate dehydrogenase
B) phosphoglycerate kinase; glyceraldehyde-3-phosphate dehydrogenase
C) phosphoribulokinase; 3-phosphoglycerate dehydrogenase
D) phosphofructokinase; pyruvate dehydrogenase
E) phosphoglycerate kinase; 3-phosphoglycerate dehydrogenase

Question 15

The Z-scheme of photosynthesis produces a 3:2 ratio of ATP:NADPH. How does a C₄ plant compensate for the greater ATP requirement created by the C₄ pathway?

A) no changes need to be made since there is more ATP available from the light reactions than actually needed for carbon fixation
B) no cyclic photophosphorylation can occur
C) more cyclic photophosphorylation must occur
D) oxygen production must be increased at photosystem II
E) oxygen production must be decreased at photosystem II

Question 16

The Z-scheme of photosynthesis produces a 3:2 ratio of ATP:NADPH. How does a plant compensate when starch or sucrose is being synthesized?

A) no changes need to be made since there is more ATP available from the light reactions than actually needed for carbon fixation
B) no cyclic photophosphorylation can occur
C) more cyclic photophosphorylation must occur
D) more NADPH must be made
E) none of the above

Question 17

Fluorescence and exciton transfer are the two mechanisms by which an excited chlorophyll molecule can productively transfer energy; heat and photooxidation are unproductive mechanisms for energy transfer.

Question 18

Cyclic electron flow allows the chloroplast to produce a greater amount of NADPH than it would under non-cyclic electron flow.