Chapter 10

Question 1

Plants are green because

A. chlorophylls absorb blue and orange-red wavelengths of light and reflect green light.
B. chloroplasts capture energy of green photons for photosynthesis.
C. energized chlorophyll a emits green light.
D. plants only have green pigments.
E. chlorophyll molecules absorb green light for photosynthesis.

Answer 1

A

Question 2

Photosynthesis and respiration have which of the following in common?

A. In eukaryotes, both processes reside in specialized organelles.
B. ATP synthesis in both processes relies on the chemiosmotic mechanism.
C. Both use electron transport.
D. Both require light.
E. a, b, and c

Answer 2

E

Question 3

The Calvin cycle uses ___ to produce carbohydrate.

A. CO2
B. ATP
C. NADPH
D. rubisco
E. All of the above

Answer 3

E

Question 4

Which of the following statements is false concerning photosynthesis?

A. Photosynthesis is an andergonic process.
B. Photosynthesis converts light energy to chemical energy.
C. Photosynthesis involves electron transport through two electron transport chains.
D. Photosynthesis is exactly cellular (aerobic) respiration in reverse.
E. Photosynthesis is an anabolic process.

Answer 4

D

Question 5

Which of the following is the revised, balanced equation for photosynthesis?

A. 6 CO2 + 6 H2O –> C6H12O6 + O2
B. 6 CO2 + 12 H2O –> C6H12O6 + 6 O2 + 6 H2O
C. 6 CO2 + 6 H2O –> C6H12O6 + 6 O2
D. 12 CO2 + 12 H2O –> 2 C6H12O6 + 2 O2
E. None of the above

Answer 5

B

Question 6

The precise moment when light energy is captured in chemical energy is the point at which

A. light shines on chlorophyll.
B. water is hydrolyzed.
C. chlorophyll is oxidized.
D. chlorophyll is reduced.
E. the CO2 from air is captured in a sugar.

Answer 6

C

Question 7

The first phase of photosynthesis, a series of reactions that requires the absorption of photos to form ATP and NADPH, is referred to as the ___ phase.

A. reduction
B. dark reactions
C. carbon fixations
D. light reactions (or photophosphorylation)
E. None of the above

Answer 7

D

Question 8

In photosynthesis, light energy is sued to extract hydrogen atoms from ___ and ultimately transfer therm to ___.

A. glucose; water
B. chlorophyll; glucose
C.water; CO2
D. water; oxygen
E. None fo the above

Answer 8

C

Question 9

Which of the following occurs during the light-independent reactions of photosynthesis?

A. Water is split into hydrogen and oxygen.
B. CO2 is ocnverted into sugars.
C. Chlorophyll is oxidized.
D. ATP is synthesized.
E. All of the above

Answer 9

B

Question 10

The O2 gas produced during photosynthesis is derived from

A. CO2.
B. glucose.
C. water.
D. CO.
E. bicarbonate ions.

Answer 10

C

Question 11

The Calvin cycle results int eh production of

A. glucose.
B. starch.
C. rubisco.
D. G3P.
E. ATP.

Answer 11

D

Question 12

In plant cells, the electron transport chains of photosynthesis

A. are located in the thylakoid membranes ot the chloroplasts.
B. are located int eh stroma of the chloroplasts.
C. are located in the cristae of the mitochondria.
D. hydrolyze ATP rather than synthesize it.
E. are directly involved in sugar synthesis.

Answer 12

A

Question 13

In noncyclic photosynthetic electron transport, water is used to

A. excite chlorophyll.
B. hydrolyze ATP.
C. reduce Pi.
D. oxidize NADPH.
E. reduce chlorophyll.

Answer 13

E

Question 14

Which statement about light is true?

A. An absorption spectrum is a plot of biological effectiveness versus wavelength.
B. An absorption spectrum may be a good means of identifying a pigment.
C. Light need not be absorbed to produce a biological effect.
D. A given kind of molecule can occupy any energy level.
E. A pigment loses energy as it absorbs a photon.

Answer 14

B

Question 15

Which statement about chlorophylls is not true?

A. Chlorophylls absorb light near both ends of the visible spectrum.
B. Chlorophylls can accept energy from other pigments, such as carotenoids.
C. Excited chlorophyll can either reduce another substance or release light energy.
D. Excited chlorophyll cannot be an oxidizing agent.
E. Chlorophylls contain magnesium.

Answer 15

D

Question 16

In cyclic electron transport,

A. oxygen gas is released.
B. ATP is formed.
C. water donates electrons and protons.
D. NADPH forms.
E. CO2 reacts with RuBP.

Answer 16

B

Question 17

Which of the following does not happen in noncyclic electron transport?

A. Oxygen gas is released.
B. ATP forms.
C. Water donates electrons and protons.
D. NADPH forms.
E. CO2 reacts with RuBP.

Answer 17

E

Question 18

In chloroplasts,

A. light leads to the flow of protons out of the thylakoids.
B. ATP is formed when protons flow into the thylakoid lumen.
C. light causes the thylakoid lumen to become less acidic than the stroma.
D. protons return passively to the stroma through protein channels.
E. proton pumping requires ATP.

Answer 18

D

Question 19

Which statement about the Calvin cycle is not true?

A. CO2 reacts with RuBP to form 3PG.
B. RuBP forms by the metabolism of 3PG.
C. ATP and NADPH form when 3PG is oxidized.
D. The concentration of 3PG rises if the light is switched off.
E. Rubisco catalyzes the reaction of CO2 and RuBP.

Answer 19

D

Question 20

In C4 photosynthesis,

A. 3PG is the first product of CO2 fixation.
B. rubisco catalyzes the first step in the pathway.
C. 4-carbon acids are formed by PEP carboxylase in bundle sheath cells.
D. photosynthesis continues at lower CO2 levels than in C3 plants.
E. CO2 released from RuBP is transferred to PEP.

Answer 20

D

Question 21

Photosynthesis in green plants occurs only during the day. Respiration in plants occurs

A. only at night.
B. only when there is enough ATP.
C. only during the day.
D. all the time.
E. in the chloroplast after photosynthesis.

Answer 21

D

Question 22

Photorespiration

A. takes place only in C4 plants.
B. includes reactions carried out in peroxisomes.
C. increases the yield of photosynthesis.
D. is catalyzed by PEP carboxylase.
E. is independent of light intensity.

Answer 22

B

Question 23

Which of the following statements about photosynthesis is false?

A. The light-independent reactions occur in the dark.
B. The Calvin cycle takes place in the stroma.
C. Oxygen is produced by thylakoid membranes.
D. ATP and NADPH link the light reactions and the light-independent reactions.
E. CO2 is reduced to sugars.

Answer 23

A

Question 24

Which of the following statements regarding light absorption and photosynthesis is false?

A. Red and blue light are effective in driving photosynthesis.
B. Chlorophyll appears green because it absorbs green light.
C. Light energy absorbed by chlorophyll may be transferred to a neighboring molecule.
D. The action spectrum for photosynthesis resembles the absorption spectrum of chlorophyll.
E. Absorption of a photon can boost a molecule to an excited, higher energy state.

Answer 24

B

Question 25

Which statement about a photosystem is false? A. Only the reaction center chlorophyll becomes oxidized in the light. B. The majority of pigment molecules serve as antennae or light harvesting molecules. C. Most of the light absorbed is re-emitted as fluorescence. D. Chemical work is done. E. Energy transfer among pigments takes place.

Answer 25

C

Question 26

Which of the following statements about the activities of photosystems I and II is false? A. Water is oxidized by photosystem II. B. Photons are required to drive both photosystems. C. The reaction center chlorophylls differ in the two photosystems. D. Sustained, noncyclic ATP production requires the activities of both photosystem I and photosystem II. E. The reduction of NADP+ to NADPH is carried out by photosystem II.

Answer 26

E

Question 27

Which of the following statements related to electron transport in photosynthesis is true? A. Water is a strong reducing agent. B. Reaction center chlorophylls are not part of the electron transport chain. C. NADPH is a weak reducing agent. D. Non-cyclic electron transport may be represented as: H2O + NADP+ → ½ O2 + NADPH + H+. E. Non-cyclic electron transport is not coupled to ATP synthesis.

Answer 27

D

Question 28

Which of the following statements correctly describes cyclic electron transport? (See figure.) A. Cyclic electron transport requires both photosystems I and II. B. Cyclic electron transport produces NADPH. C. Cyclic electron transport involves photosystem I, ferredoxin, and the electron transport chain between the two photosystems. D. There is a net oxidation of P700 during cyclic electron transport. E. There is no product of cyclic electron transport.

Answer 28

C

Question 29

Based on the figure here, which of the following partial reactions of the chloroplast electron transport chain would generate a proton-motive force in the light? A. H2O to PQ B. : PC to Fd C. Fd to NADP+ D. PQ to PC E. A and D

Answer 29

E

Question 30

Which of the following statements about the Calvin cycle (see figure) is false? A. The reactions of the Calvin cycle cease shortly after the light is switched off. B. Carbon dioxide fixation produces a compound called 3-phosphoglycerate (3PG). C. Ribulose bisphosphate (RuBP) reacts with CO2. D. CO2 reduction requires ATP and NADPH. E. 3-Phosphoglycerate is a phosphorylated sugar.

Answer 30

E This statement is false. 3PG is a carboxylic acid. The COOH group of 3PG is reduced by NADPH to an aldehyde group. The resulting compound, glyceraldehyde 3-phosphate, is a phosphorylated sugar.

Question 31

Photorespiration A. consumes CO2 and releases O2. B. occurs in all green plants. C. is initiated by the oxygenation of RuBP. D. is most rapid when the ratio of CO2 to O2 in chloroplasts is high. E. occurs in the dark.

Answer 31

C

Question 32

The accompanying figure shows the arrangement of cells in the leaves of a C3 plant and of a C4 plant. Which of the following is not a difference between C3 and C4 plants? A. The bundle sheath cells of C4 plants have rubisco, whereas bundle sheath cells in the C3 plant have little rubisco. B. The first product of photosynthesis in C3 plants is a 3-carbon molecule (3PG). C. C4 plants have two enzymes for carbon fixation, whereas C3 plants have only one. D. Photosynthesis in C3 plants occurs in the mesophyll. E. C3 plants have high rates of photorespiration.

Answer 32

D

Question 33

This figure shows two cells from a C4 plant. Select the answer that correctly completes this sentence: The lower cell in this figure is characterized by a _______ carbon fixation pathway, a _______ CO2/O2 ratio in the cell, and the major carbon fixation enzyme is \_\_\_\_\_\_\_. A. C3; Low; Rubisco B. C3; High; Rubisco C. C3 and C4; High; Rubisco D. C3 and C4; High; PEP Carboxylase E. C4; Low; PEP Carboxylase

Answer 33

C

Question 34

Which of the following statements about the Calvin cycle and cellular respiration is false? A. The carbohydrates synthesized in the dark reactions are used to fuel cellular respiration. B. Both cellular respiration and fermentation can occur in plants. C. G3P produced in the Calvin cycle can be converted to pyruvate. D. Cellular respiration in leaves occurs only at night E. Most of the G3P from the Calvin cycle can be used for sucrose synthesis in the cytoplasm.

Answer 34

D

Question 35

Plants that carry out crassulacean acid metabolism (CAM) differ from C4 plants in that A. CAM plants do not contain PEP carboxylase. B. CAM plants open their stomata only at night. C. the first product of CO2 fixation in CAM plants is 3PG. D. CAM plants are adapted to wet environments. E. CAM plants have high rates of photorespiration.

Answer 35

B

Question 36

The Calvin cycle maybe divided into three phases: CO2 fixation (A), Reduction (B), and Regeneration of RuBP (C). Per CO2 fixed, how many molecules of ATP are used in each phase of the cycle? A. A–0, B–1, C–2 B. A–0, B–2, C–1 C. A–1, B–1, C–1 D. A–0, B–1, C–1 E. A–0, B–3, C–0

Answer 36

B

Question 37

Which statement about activation of the Calvin cycle in the light is false? A. NADPH is the source of electrons for the reduction of disulfide bond to dithiols. B. Four enzymes of the cycle are reduced in the light. C. Reduced ferredoxin reduces thioredoxin. D. Reduced thioredoxin reduces disulfide bonds in the enzymes. E. The reduced enzymes are more active than the oxidized enzymes.

Answer 37

A

Question 38

Calvin cycle

Answer 38

stage in photosynthesis in which CO2 reacts with RuBP to form 3PG, which is then reduced to a sugar, and RuBP is regenerated other products are released to the rest of the plant

Question 39

Calvin cycle

Answer 39

Question 40

light rxns

Answer 40

initial phase of photosynthesis; light energy is converted to chemical energy

Question 41

photosystem | (definition)

Answer 41

light-harvesting complex in chloroplast thylakoid composed of pigments and proteins

Question 42

photosystem | (composition)

Answer 42

pigments and proteins

Question 43

bundle sheath cell

Answer 43

part of tissue surrounding veins of plants contains chloroplasts in C4 plants

Question 44

cyclic electron transport

Answer 44

flow of electrons that produces ATP but no NADPH or oxygen in photosynthetic light rxns

Question 45

stoma

Answer 45

small opening in plant epidermix that permits gas exhange bounded by pair of guard cells that regulated opening/closing through intracellular pressure

Question 46

oxygenase

Answer 46

enzyme that oxidizes a substrate by transferring the oxygen from molecular oxygen O2 (as in air)

Question 47

photosystem II

Answer 47

reactions absorbing light at 660 nm electrons passed to electron transport chain in chloroplast rich in chlorophyll *b*

Question 48

carotenoid

Answer 48

yellow, orange, or red lipid pigment commonly found as an accessory pigment in photosynthesis

Question 49

antenna system

Answer 49

group of different molecules that cooperte to absorb light and transfer it to rxn center

Question 50

rubisco

Answer 50

enzyme that combines CO2 or O2 with ribulose biphosphate to catalyze the first step of photosynthetic carbon fixation (CO2) or photorespiration (O2)

Question 51

light independent rxns

Answer 51

phase in photosynthesis in which chemical energy captured in light rxns is used to drive reduction of CO2 to form carbohydrates

Question 52

noncyclic electron transport

Answer 52

flow of electrons that forms ATP, NADPH, and O2 in photosynthesis

Question 53

pigment

Answer 53

substance that absorbs visible light

Question 54

photon

Answer 54

quantum of visible radiation or, "packet" of light energy

Question 55

autotroph

Answer 55

organism capable of living exclusively on nonorganic materials, water, and some sort of energy source (sunlight of chemically reduced matter)

Question 56

crassulacean acid metabolism | (abbreviation)

Answer 56

CAM | (long form)

Question 57

crassulacean acid metabolism (CAM)

Answer 57

metabolic pathway enabling these plants to store CO2 at night and perform photosynthesis during the day while stomata are closed

Question 58

chlorophyll

Answer 58

green pigments responsible for trapping light energy for photosynthesis

Question 59

phycobilin

Answer 59

photosynthetic pigment that absorbs red, yellow, orange, and green light founnd in cyanobacteria and some red algae

Question 60

photosystem I

Answer 60

rxns in photosynthesis that absorb light at 700 nm electrons are passed to ferrodoxin and NADPH rich in chlorophyll *a*

Question 61

PEP carboxylase

Answer 61

enzyme that combines CO2 with PEP to form 4-carbon dicarboxylic acid at the start of C4 photosynthesis or CAM

Question 62

absorption spectrum

Answer 62

graph of light absorption versus light wavelength shows how much light is absorbed at each wavelength

Question 63

photorespiration

Answer 63

light-driven uptake of O2 and release of CO2, where carbon is derived from early rxns of photosynthesis

Question 64

C4 plants

Answer 64

plants that produce oxaloacetate as the first stable product of carbon fixation in photosynthesis use phosphoenolpyruvate as CO2 acceptor

Question 65

action spectrum

Answer 65

graph of biological process versus light wavelength shows which wavelengths are involved in the process

Question 66

carboxylase

Answer 66

enzyme that catalyzes the addition of carboxyl groups to a substrate

Question 67

heterotroph

Answer 67

organism that requires preformed organic molecules as food

Question 68

C3 plants

Answer 68

plants that produce 3PG as the first stable product of carbon fixation in photosynthesis use ribulose biphosphate as CO2 receptor

Question 69

rxn center

Answer 69

group of electron transfer proteins that receive energy from light-absorbing pigments and convert it to chemical energy through redox rxns

Question 70

stage in photosynthesis in which CO2 reacts with RuBP to form 3PG, which is then reduced to a sugar, and RuBP is regenerated other products are released to the rest of the plant

Answer 70

Calvin cycle

Question 71

Answer 71

Calvin cycle

Question 72

initial phase of photosynthesis; light energy is converted to chemical energy

Answer 72

light rxns

Question 73

light-harvesting complex in chloroplast thylakoid composed of pigments and proteins

Answer 73

photosystem | (definition)

Question 74

part of tissue surrounding veins of plants contains chloroplasts in C4 plants

Answer 74

bundle sheath cell

Question 75

flow of electrons that produces ATP but no NADPH or oxygen in photosynthetic light rxns

Answer 75

cyclic electron transport

Question 76

small opening in plant epidermix that permits gas exhange bounded by pair of guard cells that regulated opening/closing through intracellular pressure

Answer 76

stoma

Question 77

enzyme that oxidizes a substrate by transferring the oxygen from molecular oxygen O2 (as in air)

Answer 77

oxygenase

Question 78

reactions absorbing light at 660 nm electrons passed to electron transport chain in chloroplast rich in chlorophyll *b*

Answer 78

photosystem II

Question 79

yellow, orange, or red lipid pigment commonly found as an accessory pigment in photosynthesis

Answer 79

carotenoid

Question 80

group of different molecules that cooperte to absorb light and transfer it to rxn center

Answer 80

antenna system

Question 81

enzyme that combines CO2 or O2 with ribulose biphosphate to catalyze the first step of photosynthetic carbon fixation (CO2) or photorespiration (O2)

Answer 81

rubisco

Question 82

phase in photosynthesis in which chemical energy captured in light rxns is used to drive reduction of CO2 to form carbohydrates

Answer 82

light independent rxns

Question 83

flow of electrons that forms ATP, NADPH, and O2 in photosynthesis

Answer 83

noncyclic electron transport

Question 84

substance that absorbs visible light

Answer 84

pigment

Question 85

quantum of visible radiation or, "packet" of light energy

Answer 85

photon

Question 86

organism capable of living exclusively on nonorganic materials, water, and some sort of energy source (sunlight of chemically reduced matter)

Answer 86

autotroph

Question 87

CAM | (long form)

Answer 87

crassulacean acid metabolism | (abbreviation)

Question 88

metabolic pathway enabling these plants to store CO2 at night and perform photosynthesis during the day while stomata are closed

Answer 88

crassulacean acid metabolism (CAM)

Question 89

green pigments responsible for trapping light energy for photosynthesis

Answer 89

chlorophyll

Question 90

photosynthetic pigment that absorbs red, yellow, orange, and green light founnd in cyanobacteria and some red algae

Answer 90

phycobilin

Question 91

rxns in photosynthesis that absorb light at 700 nm electrons are passed to ferrodoxin and NADPH rich in chlorophyll *a*

Answer 91

photosystem I

Question 92

enzyme that combines CO2 with PEP to form 4-carbon dicarboxylic acid at the start of C4 photosynthesis or CAM

Answer 92

PEP carboxylase

Question 93

graph of light absorption versus light wavelength shows how much light is absorbed at each wavelength

Answer 93

absorption spectrum

Question 94

light-driven uptake of O2 and release of CO2, where carbon is derived from early rxns of photosynthesis

Answer 94

photorespiration

Question 95

plants that produce oxaloacetate as the first stable product of carbon fixation in photosynthesis use phosphoenolpyruvate as CO2 acceptor

Answer 95

C4 plants

Question 96

graph of biological process versus light wavelength shows which wavelengths are involved in the process

Answer 96

action spectrum

Question 97

enzyme that catalyzes the addition of carboxyl groups to a substrate

Answer 97

carboxylase

Question 98

organism that requires preformed organic molecules as food

Answer 98

heterotroph

Question 99

plants that produce 3PG as the first stable product of carbon fixation in photosynthesis use ribulose biphosphate as CO2 receptor

Answer 99

C3 plants

Question 100

group of electron transfer proteins that receive energy from light-absorbing pigments and convert it to chemical energy through redox rxns

Answer 100

rxn center