[PM] Photosynthesis

Question 1

The light reactions of photosynthesis occur in the ___ membrane of the chloroplast.

Answer 1

thylakoid

Question 2

In the dark reactions of photosynthesis, glyceraldehyde-3-phosphate is converted to dihydroxyacetone phosphate by ___.

Answer 2

triose phosphate isomerase

Question 3

Synthesis of sucrose requires which of the following?
I. glyceraldehyde-3-phosphate and/or dihydroxyacetone phosphate
II. sucrose phosphate kinase
III. sucrose sucrose phosphate phosphatase
IV. UTP

Answer 3

I, III, and IV

Question 4

In which part of the chloroplast does production of oxygen during photosynthesis primarily occur?

Answer 4

Thykaloid disks

Question 5

In which part of the chloroplast does production of oxygen during photosynthesis primarily occur?

Answer 5

Thylakoid disks

Question 6

Green plants contain ___.

Answer 6

both chlorophyll a and b

Question 7

Which of the following is NOT a component of the electron transport chain that links Photosystem I and Photosystem II?

Answer 7

NADPH

Question 8

The process of ATP synthesis in chloroplasts is referred to as ___.

Answer 8

photophosphorylation

Question 9

The terminal electron acceptor during the light phase of photosynthesis in green plants is ___.

Answer 9

NADP+

Question 10

Light energy absorbed in chloroplasts is used in the light phase for all reactions except

Answer 10

reduce water; reduce H2O to make O2

Question 11

Determine the order of the light reactions during the light phase of photosynthesis:
1. Light absorption in Photosystem I
2. Light absorption in Photosystem II
3. Formation of O2 from water
4. Formation of NADPH
5. Formation of ATP

Answer 11

3→2→5→1→4

Question 12

The actual CO2 fixation process in photosynthesis is the addition of CO2 into a 5 carbon compound to yield ___.

Answer 12

3-phosphoglycerate

Question 13

In the first reaction of carbon dioxide fixation in photosynthesis, CO2 reacts with ___.

Answer 13

ribulose-1,5-bisphosphate

Question 14

The essential enzyme for the C4 pathway is ___.

Answer 14

Phosphoenolpyruvate carboxylase

Question 15

Which of the following is NOT an intermediate in the C4 pathway?

Answer 15

fumarate

Question 16

Pheophytins are structurally similar to ___ except they possess hydrogen atoms instead of a metal ion.

Answer 16

Chlorophyll

Question 17

The six-carbon precursor of amylose in plants is ___.

Answer 17

Glucose-1-phosphate

Question 18

Which of the following is a product of Calvin cycle?

Answer 18

Glyceraldehyde-3-phosphate

Question 19

What is the source of carbon for Calvin cycle?

Answer 19

carbon dioxide

Question 20

How many protons are transferred into the thykaloid lumen after absorption of four photons?

Answer 20

12

Question 21

The region of the chloroplast between the inner membrane and the thylakoid membrane is called
a. the stroma.
b. the thylakoid space.
c. the intermembrane space.
d. the grana.

Answer 21

a. the stroma

Question 22

In chloroplasts,
a. the light reactions take place in the thylakoid disks, whereas the dark reactions occur in the stroma
b. the dark reactions take place in the thylakoid disks, whereas the light reactions occur in the stroma
c. the light reactions take place in the thylakoid space, whereas the dark reactions occur in the stroma
d. the dark reactions take place in the thylakoid space, whereas the light reactions occur in the stroma

Answer 22

a. the light reactions take place in the thylakoid disks, whereas the dark reactions occur in the stroma

Question 23

In which part of the chloroplast does production of oxygen during photosynthesis primarily occur?
a. Grana.
b. Thylakoid disks.
c. Stroma.
d. Thylakoid space.
e. It is not known where this reaction occurs in the chloroplast.

Answer 23

b. Thylakoid disks

Question 24

In which part of the chloroplast does reduction of CO2 during photosynthesis primarily occur?
a. Grana.
b. Thylakoid disks.
c. Stroma.
d. Thylakoid space.
e. It is not known where this reaction occurs in the chloroplast.

Answer 24

c. Stroma

Question 25

Accessory pigments a. transfer electrons to reaction center chlorophylls. b. transfer energy to reaction center chlorophylls. c. transfer electrons from reaction center chlorophylls to phaeophytins. d. transfer electrons from reaction center chlorophylls to ferredoxin. e. All of these statements are true.

Answer 25

b. transfer energy to reaction center chlorophylls.

Question 26

Photosynthetic bacteria which do not use water as the ultimate source of electrons a. only contain chlorophyll a. b. only contain chlorophyll b. c. do not produce oxygen. d. have two photosystems.

Answer 26

c. do not produce oxygen.

Question 27

The key element at the center of chlorophyll is a. chlorine. b. copper. c. iron. d. magnesium. e. manganese.

Answer 27

d. magnesium.

Question 28

Cyanobacteria contain a. only chlorophyll a. b. only chlorophyll b. c. both chlorophyll a and chlorophyll b. d. bacteriochlorophyll.

Answer 28

a. only chlorophyll a.

Question 29

Two different types of chlorophyll are used by most plants for the following reason: a. Two chlorophylls allow for absorbing light from a larger portion of the light spectrum. b. The different chorophylls are used in different parts of the photosynthesis process. c. One type is used in photosystem I and the other in phototsystem II. d. The different chlorophylls are located in different compartments of the chloroplast. e. It is not know why there are two different chlorophylls.

Answer 29

a. Two chlorophylls allow for absorbing light from a larger portion of the light spectrum.

Question 30

Wavelengths of what color are mostly responsible for the reactions in the light phase of photosynthesis? a. Blue. b. Green. c. Red. d. Blue and red. e. All three colors.

Answer 30

d. Blue and red.

Question 31

Green plants contain a. only chlorophyll a. b. only chlorophyll b. c. both chlorophyll a and chlorophyll b. d. bacteriochlorophyll.

Answer 31

c. both chlorophyll a and chlorophyll b.

Question 32

Which of the following is true concerning chlorophyll? a. It absorbs green light, which is why leaves are green b. Chlorophyll a and b each have peaks of absorption at two different wavelengths c. Chlorophyll a has a maximum absorption at 600 nm d. Between the two chlorophylls, light is absorbed between 400 and 700 mm

Answer 32

b. Chlorophyll a and b each have peaks of absorption at two different wavelengths

Question 33

Chlorophyll differs from heme because it a. has a cyclohexene ring fused to the tetrapyrrole ring system b. has a 16-carbon unbranched side chain. c. contains magnesium rather than iron. d. has a fully saturated tetrapyrrole ring.

Answer 33

c. contains magnesium rather than iron.

Question 34

While chlorophyll contains a different metal ion, its ring structure is very similar to the ring structure in steroids. a. True b. False

Answer 34

b. False

Question 35

Light with short wavelengths has less energy than light with long wavelengths. a. True b. False

Answer 35

b. False

Question 36

A specialized pair of chlorophylls exists at a. the antenna complexes. b. the accessory pigments. c. the reaction centers. d. the stroma.

Answer 36

c. the reaction centers.

Question 37

The light reactions drive the redox process that involves the following pairs of reactants/products a. H2O/O2 and NADP+/NADPH b. H2O/O2 and NADH/NAD+ c. O2/H2O and NADPH/NADP+ d. H2O/O2 and FAD/FADH2

Answer 37

a. H2O/O2 and NADP+/NADPH

Question 38

Which of the following is not a component of the electron transport chain that links Photosystem I and Photosystem II? a. NADPH b. pheophytin c. plastoquinone d. cytochrome f

Answer 38

a. NADPH

Question 39

The light phase of photosynthesis is closest to which other metabolic process? a. Anaerobic Glycolysis. b. The Pentose Monophosphate Pathway. c. The Kreb's Cycle. d. The Electron Transport System e. The reactions in the light phase are not similar to any other pathway.

Answer 39

d. The Electron Transport System

Question 40

The process of ATP synthesis in chloroplasts is referred to as a. oxidative phosphorylation. b. photophosphorylation c. reductive phosphorylation d. substrate-level phosphorylation.

Answer 40

b. photophosphorylation

Question 41

Which of the following statements concerning the light reactions of photosynthesis is false? a. Photophosphorylation results from the proton gradient across the thylakoid membrane. b. Photosystem II is devoted to water oxidation. c. P700 is Photosystem II. d. Photosystem I is devoted to NADP+ reduction.

Answer 41

c. P700 is Photosystem II.

Question 42

The transfer of electrons from water to NADP+ to produce oxygen and NADPH is a highly exergonic process. a. True b. False

Answer 42

b. False

Question 43

The terminal electron acceptor during the light phase of photosynthesis in green plants is a. Hydrogen (H2 → H2O). b. NAD+ (→ NADH). c. NADP+ (→ NADPH). d. Oxygen (O2 → H2O). e. Sulfur (→ H2S).

Answer 43

d. Oxygen (O2 → H2O).

Question 44

Which of the following statements concerning the light reactions of photosynthesis is false? a. There are two photosystems linked by an electron transport chain b. Electron transport is coupled to production of ATP c. The production of NADPH is carried out by Photosystem I, whereas the splitting of water is carried out by Photosystem II d. Carbon dioxide fixation takes place

Answer 44

d. Carbon dioxide fixation takes place

Question 45

Light energy absorbed in chloroplasts is used in the light phase for all of these reactions, except: a. To reduce water. b. To make ATP. c. To generate NADPH. d. To reduce water and to generate oxygen, O2. e. All of these occur during the light phase.

Answer 45

d. To reduce water and to generate oxygen, O2.

Question 46

The oxygen evolving complex consists of a. accessory pigments. b. a manganese-containing protein. c. the reaction center chlorophylls. d. ferredoxin.

Answer 46

b. a manganese-containing protein.

Question 47

The electrons used in photosynthesis come first from this molecule or atom: a. Hydrogen (H2). b. Manganese atom (Mn). c. NADPH d. Oxygen (O2). e. Water (H2O).

Answer 47

e. Water (H2O).

Question 48

The reactions during the light phase of photosynthesis include the following: 1. Light absorption in photosystem I 2. Light absorption in photosystem II 3. Formation of O2 from water 4. Formation of NADPH 5. Formation of ATP The order of the reactions is as follows: a. 4 → 2 → 3 → 1 → 5. b. 3 → 2 → 5 → 1 → 4. c. 3 → 1 → 5 → 2 → 4 d. 4 → 1 → 5 → 2 → 3 e. 5 → 2 → 4 → 1 → 3.

Answer 48

b. 3 → 2 → 5 → 1 → 4.

Question 49

Which of the following correctly describes a major difference between pheophytins and chlorophylls? a. Pheophytins contain iron in their centers while chlorophylls contain magnesium. b. Chlorophylls contain iron in their centers while pheophytins contain magnesium. c. Pheophytins contain no metal ion in their centers. d. Pheophytins aren't at all like chlorophylls, but are quinones.

Answer 49

c. Pheophytins contain no metal ion in their centers.

Question 50

Which of the following statements concerning the photosynthetic reaction center of Rhodopseudomonas viridis is false? a. There is a pair of chlorophylls in a special environment. b. Accessory pigments play a role in trapping of light. c. A separation of charge represents stored energy. d. The electrons being transferred can take either of two possible paths.

Answer 50

d. The electrons being transferred can take either of two possible paths.

Question 51

Which of the following is true? a. A protein with a manganese ion is key to the conversion of O2 to water b. The electron transport chain in photosynthesis is identical to the one in mitochondria c. Parts of the electron transport chain in photosynthesis are similar to the electron transport chain in mitochondria d. Photosynthesis is the exact opposite of respiration

Answer 51

c. Parts of the electron transport chain in photosynthesis are similar to the electron transport chain in mitochondria

Question 52

Which of the following is the mobile electron carrier from Photosystem Il to the cytochrome b6f complex? a. plastoquinone b. pheophytin c. plastocyanin d. ferredoxin

Answer 52

a. plastoquinone

Question 53

During cyclic electron transport a. only Photosystem II is involved. b. only Photosystem I is involved. c. both photosystems are involved. d. neither photosystem is involved.

Answer 53

b. only Photosystem I is involved.

Question 54

During Z-scheme photosynthesis, ferredoxin oxidizes NADPH. a. True b. False

Question 55

Ferredoxin is important in photosynthesis in forming NADH. a. True b. False

Question 56

It is believed that the ratio of cyclic electron transport to Z-scheme photosynthesis changes in response to metabolic demands. If a plant were actively synthesizing starch from the glucose produced, how would it alter these processes compared to a plant just performing the Calvin cycle to produce glucose? a. More cyclic photophosphorylation, less Z-scheme. b. More Z-scheme photosynthesis, less cyclic photophosphorylation. c. No significant difference. d. Impossible to predict from the information provided

Question 57

It is believed that the ratio of cyclic electron transport to Z-scheme photosynthesis changes in response to metabolic demands. If a plant were using the C. Hatch-Slack pathway, how would it alter these processes compared to a plant just performing the standard C. Calvin cycle to produce glucose? a. More cyclic photophosphorylation, less Z-scheme. b. More Z-scheme photosynthesis, less cyclic photophosphorylation. c. No significant difference. d. Impossible to predict from the information provided.

Question 58

It is believed that the ratio of cyclic electron transport to Z-scheme photosynthesis changes in response to metabolic demands. If a plant were actively engaged in a large amount of reductive biosynthesis, requiring NADPH, how would it alter these processes compared to a plant just performing the Calvin cycle to produce glucose? a. More cyclic photophosphorylation, less Z-scheme. b. More Z-scheme photosynthesis, less cyclic photophosphorylation. C. No significant difference. d. Impossible to predict from the information provided.

Question 59

While actively engaging in photosynthesis under illumination, a. the pH of the thylakoid space would be lower than that of the stroma. b. the pH of the thylakoid space would be greater than that of the stroma. c. the pH of the thylakoid space and of the stroma would be about the same. d. it would be impossible to predict the relative pH's of the thylakoid space and of the stroma.

Question 60

The synthesis of ATP in chloroplasts uses a proton gradient similar to the one used in mitochondria. a. True b. False

Question 61

The ATP synthase in photosynthesis is similar in structure and function to its mitochondrial counterpart. a. True b. False

Question 62

The production of ATP in photosynthesis a. is not linked to a proton gradient across a membrane b. does not involve membrane-bound proteins c. does not require the presence of light d. provides the energy for production of sugars

Question 63

Anaerobic, photosynthetic bacteria differ from green plants in that they only have one type of chlorophyll. a. True b. False

Question 64

Bacterial products of photosynthesis, other than oxygen and sugars, can include all of these, except: a. H2S b. NH3 c. CH4 d. Water e. All of these are products of photosynthetic bacteria.

Question 65

The earliest photosynthetic organisms most likely used water as an electron source. a. True b. False

Question 66

After the reaction with Rubisco, the major difference between the Calvin Cycle and gluconeogenesis in liver is the following reaction: a. The reduction of 1,3 bisphosphoglyceric acid uses NADPH instead of NADH b. The formation of 1,3 bisphosphoglyceric acid from 3-phosphoglyceric acid uses GTP instead of ATP. c. Phosphatases are not required in plants. d. The reduction of 1,3 bisphosphoglyceric acid uses NADH instead of NADPH e. More than one of these reactions is substantially different in plants compared to liver.

Question 67

Where does the actual CO, fixation process takes place? a. the stroma. b. the thylakoid space. c. the intermembrane space. d. the cytosol.

Question 68

The dark phase of photosynthesis is closest to this other metabolic process: a. Anaerobic Glycolysis. b. The Pentose Phosphate Pathway. c. The Kreb's Cycle. d. The Electron Transport System e. The reactions in the dark phase are not similar to any other pathway.

Question 69

The actual CO, fixation process in photosynthesis is the addition of CO, into a 5 carbon compound to yield. a. ribulose 5-phosphate. b. ribulose 1,5-bisphosphate. c. erythrose 4-phosphate. d. 3-phosphoglycerate.