Deck 15: Photosynthesis

Question 1

Most chlorophylls are green.This means they absorb in the ________ region of the visible spectrum.

A)green
B)blue-violet
C)red-orange
D)blue-violet and red-orange
E)infrared

Answer 1

blue-violet and red-orange

Question 2

What is wavelength of light if the energy of one photon is 2.925 × 10-¹⁹ J?(h = 6.63 × 10-³⁴ J s and c = 3.00 × 10⁸ m s-¹)

A)680nm
B)700 nm
C)5.8 m
D)1.5 × 10-³ nm

Answer 2

680nm

Question 3

Photosynthesis in PS I is non-cyclic because

A)it is slower than those in PS II.
B)reaction centers must be reduced by electrons from another source.
C)reaction centers are more tightly packed in the photosystem complexes.
D)there can never exist a cyclic process of electron transfer in these photosystems.

Answer 3

reaction centers must be reduced by electrons from another source.

Question 4

The source of electrons for green sulfur bacteria is ________,and the source of electrons for cyanobacteria is ________.

A)NADPH;NAD+
B)H₂S;H₂O
C)H₂O;H₂S
D)cytochrome c;cytochrome bf

Question 5

The main difference between photosynthesis and respiratory electron transport is (are)

A)the tetrapyrole ring of the pigments involved.
B)the coenzymes that carry electrons.
C)the sources of excited electrons.
D)the formation of ATP.

Question 6

Carotenoids,phycobilins,xanthophylls and chlorophyll molecules (that are not in the special pair)________.

A)can transfer light energy to chlorophylls
B)can absorb light energy
C)may prevent the formation of reactive superoxide anion
D)A,B and C
E)A and B only

Question 7

Plant pigments which can absorb light include

A)chlorophyll a.
B)chlorophyll b.
C)carotenoids and phycobilins.
D)All of the above.
E)A and B only.

Question 8

Chlorophyll molecules can exist in ________ different states.

A)2
B)3
C)4
D)5

Question 9

The formation of ATP is a(n)________ reaction in plants.

A)dark
B)light independent
C)light dependent
D)anaerobic
E)carbon fixation

Question 10

In the Z scheme describing electron flow in photosynthesis,the electron donor to P680 is ________,while the electron donor to P700 is ________.

A)H₂O;plastocyanin
B)plastocyanin;H₂O
C)O₂;plastocyanin
D)plastocyanin;O₂
E)O₂;H₂O

Question 11

Which use only type I reaction centers for photosynthesis?

A)Heliobacteria.
B)Purple bacteria.
C)Cyanobacteria.
D)Algae.

Question 12

Photosynthesis by green sulfur bacteria and cyanobacteria are different because green sulfur bacteria ________.

A)have only cyclic photosynthesis
B)use photosystem I,but not photosystem II
C)use both photosystems I and II
D)use cytochromes

Question 13

Two interdependent processes which comprise photosynthesis are (1)the formation of carbohydrates from CO₂ and (2)the formation of ________.

A)ADP
B)ATP
C)NAD+
D)NADPH
E)ATP and NADPH

Question 14

Reactions to extract electrons from water require ________ to reverse electron flow.

A)powerful oxidizing agents
B)powerful reducing agents
C)dark reactions
D)ATP

Question 15

The region of the chlorophyll molecule that helps anchor it in the membrane is the

A)Mg²+ ion.
B)chlorin ring.
C)phytol side chain.
D)tetrapyrrole ring.
E)All of the above.

Question 16

Calculate the energy of a photon with a wavelength of 700 nm.(h = 6.63 × 10-³⁴ J s and c = 3.00 × 10⁸ m s-¹)

A)2.8 × 10-²⁸ J
B)2.8 × 10-¹⁹ J
C)1.3 × 10-²² J
D)3.6 × 10¹⁸ J

Question 17

The photosynthetic dark reactions ________.

A)occur only in the dark (nocturnal)
B)are the main source of ATP in photosynthesis
C)convert carbon dioxide to carbohydrates
D)produce the reduced coenzyme NADH

Question 18

Which term is not used for a photosystem or a part of a photosystem?

A)PS I.
B)PS II.
C)Special pair.
D)Light complexes.
E)Antenna pigments.

Question 19

Cyanobacteria have evolved photosynthetic features not found in green sulfur bacteria.These include

A)cytochrome bc.
B)synthesis of NADH.
C)electron acceptor P700.
D)an oxygen-evolving complex.
E)All of the above.

Question 20

What structural feature is most responsible for chlorophyll's ability to absorb light?

A)The magnesium ion.
B)The conjugated double-bonds in the tetrapyrrole ring.
C)The phytol side chain.
D)An aromatic side chain attached to the tetrapyrrole ring.

Question 21

Which molecule is the CO₂ acceptor in the first step of the Calvin cycle?

A)Rubisco.
B)Ribulose 1,5-bisphosphate.
C)3-phosphoglycerate.
D)Glyceraldehyde-3-phosphate.

Question 22

Which statement is false about bacteriorhodopsin?

A)It occurs in archaebacteria.
B)A molecule of retinal inside bacteriorhodopsin converts from the trans to the cis configuration when light is absorbed.
C)It creates a light-induced proton gradient across a membrane.
D)Its activity is coupled to PSI and PSII.

Question 23

The Calvin cycle occurs in the ________ of plant chloroplasts and in the ________ of bacteria.

A)lumen;plasma membrane
B)stroma;cytosol
C)grana lamellae;cytosol
D)stroma;plasma membrane
E)lumen;cytosol

Question 24

The production of O₂ from water supplies an electron first for

A)photosystem I.
B)photosystem II.
C)cytochrome bf complex.
D)plastocyanin.

Question 25

Electron carriers between activated P680* and P700 photosystems include

A)plastoquinones.
B)pheophytin.
C)ferredoxin and iron - sulfur clusters.
D)All of the above.
E)A and B.

Question 26

Photon capture by plant chloroplasts is more efficient than in bacteria because they contain

A)both PS I and PS II.
B)more chlorophyll.
C)LHII,a light harvesting complex.
D)both cyclic and noncyclic photophosphorylation.

Question 27

Within the chloroplast,grana are ________.

A)stacks of enfolded thylakoid membrane
B)the stroma
C)stroma lamellae
D)the site of carbon fixation reactions

Question 28

How many ATP molecules are required for the fixation of one CO₂ molecule via the Calvin cycle to a triose phosphate?

A)1
B)2
C)3
D)4

Question 29

Which enzyme is not part of the Calvin cycle?

A)Triose phosphate isomerase.
B)Rubisco.
C)Plastocyanin.
D)Transketolase.

Question 30

Which statement is false about ferredoxin?

A)It is produced by PSII.
B)It is reduced by PSII.
C)It participates in the reduction of NADP+.
D)It can serve as an electron donor to cytochrome bf.

Question 31

Attempts to genetically modify rubisco to help increase food production might include trying to ________.

A)enhance the carboxylation reaction and suppress the oxygenation reaction
B)suppress the carboxylation reaction and enhance the oxygenation reaction
C)decrease the value of kcat by site-directed mutagenesis
D)increase rubisco's activity in the dark

Question 32

Which is not required to activate rubisco?

A)CO₂.
B)Mg²+.
C)Light.
D)NADP+.
E)All of the above are required.

Question 33

What is the product of the reaction catalyzed by rubisco in the Calvin cycle?

A)Dihydroxyacetone phosphate.
B)3-phosphoglycerate.
C)Ribose 5-phosphate.
D)Fructose 6-phosphate.

Question 34

Starting with carbon dioxide fixation,which is the correct order for the stages of the Calvin cycle?

A)Carboxylation → Reduction → Regeneration.
B)Regeneration → Carboxylation → Reduction.
C)Carboxylation → Regeneration → Reduction.
D)Reduction → Carboxylation → Regeneration.

Question 35

The site of light-dependent reactions in the chloroplast is

A)the stroma.
B)the thylakoids.
C)the outer membrane.
D)the lumen.
E)All of the above.

Question 36

Which statement is false about the photosynthesis in plants?

A)PSI reduces ferredoxin.
B)PSI produces ferredoxin.
C)ATP is synthesized in the lumen.
D)PQH₂ can diffuse within the thylakoid membrane.

Question 37

What is the correct sequence for the following components in photosynthesis as described by the Z scheme?

A)NADPH → P700 → P700* → cytochrome bf complex → P680 → P680* → water.
B)Water → P700 → P700* → cytochrome bf complex → P680* → P680 → NADPH.
C)Water → P680 → P680* → cytochrome bf complex → P700 → P700* → NADPH.
D)Water → P700 → P700* → cytochrome bf complex → P680 → P680* → NADPH.
E)NADPH → P680 → P680* → cytochrome bf complex → P700 → P700* → water.

Question 38

Which is not a name for the reactions of the Calvin cycle?

A)Proton translocation cycle.
B)Reductive pentose phosphate cycle.
C)C₃ pathway.
D)Dark reactions.

Question 39

In plants,light energy channeled to PSII and PSI drives electron transport through a series of electron carriers.At the same time,protons are translocated into the ________.

A)stroma
B)lumen
C)granum
D)plasma membrane

Question 40

Which is not directly exposed to the stroma,but is exposed to the thylakoid lumen?

A)PSI.
B)PSII.
C)both PSI and PSII.
D)None of the above because both PSI and PSII are exposed to the stroma.

Question 41

Which is the proper order of substrates in the synthesis of starch?

A)Glucose 1-phosphate → glucose 6-phosphate → ADP-glucose → starch.
B)Glucose 1-phosphate → fructose 6-phosphate → UDP-fructose → starch.
C)Glucose 3-phosphate → glucose 1-phosphate → ADP-glucose → starch.
D)Glucose 6-phosphate → glucose 1-phosphate → ADP-glucose → starch.

Question 42

On a hot summer day which would you expect about the ratio of oxygenation versus carboxylation of ribulose 1,5-bisphosphate in C₃ plants as compared to a cooler day?

A)No change because oxygenation does not occur in C₃ plants.
B)The ratio is not affected by temperature.
C)The ratio rises due to increased rate of oxygenation.
D)The ratio decreases due to decreased rate of oxygenation.

Question 43

Dark reactions of photosynthesis must occur in the absence of light.

Question 44

Photorespiration in plants involves the ________.

A)fixation of carbon dioxide to a four-carbon acid
B)light-dependent uptake of O₂ catalyzed by rubisco,followed by the release of CO₂
C)reduction of surface-exposed disulfides in the regulation of rubisco
D)exclusive fixation of carbon dioxide at night by plants such as cacti

Question 45

In CAM plants,________ is stored at night and released during the day to supply carbon dioxide.

A)glucose
B)acetate
C)phosphoenolpyruvate
D)malate

Question 46

Light energy is initially captured in plant cells by raising the energy level of an electron in the chlorophyll molecule.

Question 47

Which statement is false about C₄ plants?

A)They tend to grow at high temperatures and high light intensities.
B)They decrease the ratio of CO₂ to O₂ in cells where Rubisco is active.
C)Corn is an example of a C₄ plant.
D)They avoid wasteful photorespiration by means of secondary pathways for carbon dioxide fixation.

Question 48

What is the main advantage for plants that use the C₄ pathway in addition to the Calvin cycle for the fixation of carbon dioxide?

A)Fewer ATP are consumed to produce carbohydrates using the C₄ pathway as opposed to the Calvin cycle.
B)The C₄ pathway allows for fixation of carbon dioxide at night.
C)The C₄ pathway aids in the avoidance of the oxygenation of ribulose 1,5-bisphosphate.
D)The C₄ cycle allows photosynthesis to occur at a wide range of wavelengths of light.

Question 49

Which is not a substance produced from the carbon dioxide assimilated via the Calvin cycle?

A)Cellulose.
B)Starch.
C)Sucrose.
D)Chitin.

Question 50

Which is NOT an intermediate in the biosynthesis of starch in plants?

A)ADP-glucose.
B)UDP-glucose.
C)Glucose -1 - phosphate.
D)Glucose - 6 - phosphate.

Question 51

The nocturnal fixation of carbon dioxide in cacti helps ________.

A)stimulate photorespiration
B)minimize use of ATP
C)minimize water loss
D)transport CO₂ to the bundle sheath cells

Question 52

The synthesis of sucrose in plants occurs in the ________.

A)cytoplasm
B)chloroplast
C)vacuole
D)lumen

Question 53

The initial carbon dioxide acceptor of the C₄ pathway is ________.

A)phosphoenolpyruvate
B)oxaloacetate
C)ribulose 1,5-bisphosphate
D)PEP carboxylase

Question 54

In cacti ________ accumulates in the cell vacuoles at night that is released in the day and decarboxylated.

A)phosphoenolpyruvate
B)malate
C)oxaloacetate
D)bicarbonate ion

Question 55

The initial reactions of the C₄ pathway occur in the ________.

A)chloroplast stroma
B)mesophyll cells
C)bundle sheath cell cytosol
D)stomata plasma membrane

Question 56

Which is not an intermediate in the biosynthesis of sucrose in plants?

A)ADP-glucose.
B)Glucose 6-phosphate.
C)Fructose 6-phosphate.
D)Fructose 1,6-bisphosphate.

Question 57

The reactions that allow plants such as cacti and orchids to assimilate carbon at night are referred to as ________.

A)the Calvin cycle
B)nocturnal photorespiration
C)the C₄ pathway
D)Crassulacean acid metabolism

Question 58

The reaction catalyzed by which enzyme in the Calvin cycle is unlikely to be a regulatory step?

A)Phosphoglycerate kinase.
B)Triose phosphate isomerase.
C)Phosphoribokinase.
D)Rubisco.

Question 59

Solar energy is captured in chemical form as ATP and NADPH by the process of photosynthesis.

Question 60

The light reactions of photosynthesis form carbohydrates from ATP,NADPH,H+ and CO₂

Question 61

Photosystems I and II are located in the same region of the chloroplast structure,since both contain chlorophyll.

Question 62

Photosynthesis in PS II is cyclic,since there is no net gain or loss of electrons and no requirement for an outside source of electrons.

Question 63

Plants may lose green color as they mature if enzymes that degrade chlorophyll are activated.

Question 64

The compound 2-carboxyarabinitol 1-phosphate is present in plants only at night and is a strong activator of rubisco.

Question 65

The cytochrome bf complex connects the electron flow from photosystem I (PSI)to photosystem II (PSII)according to the Z scheme describing electron flow in photosynthesis.

Question 66

The only plant pigments responsible for light harvesting are chlorophylls.

Question 67

The light-dependent reactions are located in the thylakoid membrane of chloroplasts,while the dark reactions are located within the lumen.

Question 68

The structure of Rubisco is nearly identical in all phototrophs.All known forms of Rubisco have the same number of subunits.

Question 69

Although a variety of pigments absorb light,only the special pair of chlorophyll molecules at photosystems I and II can become activated and thereby provide electrons for transport.

Question 70

All chlorophyll are directly involved in electron transfer.

Question 71

Chlorophyll molecules contain hydrophilic regions containing bonds for light-absorbing and hydrophobic regions anchoring them to membranes.

Question 72

Chloroplasts evolved from a species of cyanobacteria that entered a eukaryotic cell over a billion years ago.

Question 73

Rubisco often makes up to 50% of the soluble protein in plant leaves.

Question 74

Vitamin K is part of the electron chain in photosystem II.

Question 75

Phycoerythrin and β-carotene absorb light in ranges broader than that absorbed by chlorophylls,and this light energy is ultimately used by the plant for photosynthesis.

Question 76

The translocation of protons across the thylakoid membrane creates a proton motive force necessary for ATP synthesis.

Question 77

Light with a wavelength of 700 nm has more energy per photon than light with a wavelength of 680 nm.

Question 78

Bacteria with PS I use sunlight to produce NADPH while those with PSII do not.

Question 79

In plants the light-harvesting complex (LHCII)completely surrounds PSII.

Question 80

All photosynthetic bacteria give off O₂ as an end-product of photosynthesis.