Deck 7: Photosynthesis, Light, and Life

Question 1

In the light reactions, the cytochrome b₆/f complex receives electrons directly from:

A)plastoquinol.
B)ferredoxin.
C)pheophytin
D)manganese.
E)plastocyanin.

Answer 1

A

Question 2

Who provided the first experimental evidence that soil alone does not nourish the plant?

A)Jan Ingenhousz
B)Aristotle
C)F.F.Blackman
D)Joseph Priestley
E)Jan Baptista van Helmont

Answer 2

E

Question 3

Light is composed of particles called:

A)electrons.
B)protons.
C)neutrons.
D)gamma rays.
E)photons.

Answer 3

E

Question 4

Which of the following events is NOT associated with Photosystem I?

A)absorption of light by antenna molecules
B)excitation of an electron from P₇₀₀
C)transfer of electrons from cytochromes to iron-sulfur proteins
D)reduction of NADP⁺
E)reduction of A_o

Question 5

Which of the following statements about an antenna complex is FALSE?

A)It is part of a photosystem.
B)It "funnels" energy to the reaction center.
C)It contains chlorophyll molecules.
D)It contains carotenoid pigments.
E)It converts light energy into chemical energy.

Question 6

Xanthophylls and carotenes:

A)are the principal photosynthetic pigments in green plants.
B)are the principal sources of vitamin C for humans.
C)are carotenoids.
D)are normally present in the cytosol rather than in plastids.
E)can substitute for chlorophylls in photosynthesis.

Question 7

In the antenna complex, light energy is transferred from one pigment molecule to another by:

A)pigment activation.
B)fluorescence.
C)resonance energy transfer.
D)reduction.
E)oxidation.

Question 8

Which pigment occurs in all photosynthetic eukaryotes?

A)Chlorophyll a
B)Chlorophyll b
C)Chlorophyll c
D)Bacteriochlorophyll
E)Chlorobium chlorophyll

Question 9

The O₂ evolved in photosynthesis comes from:

A)carbon dioxide.
B)water.
C)glucose.
D)(CH₂O).
E)(C₃H₃O₃).

Question 10

The primary function of ______ is as an anti-oxidant.

A)chlorophyll a
B)carotenoids
C)phycobilins
D)bacteriochlorophyll
E)chlorobium chlorophyll

Question 11

The ______ complex links photosystems I and II.

A)ATP synthase
B)light-harvesting
C)oxygen-evolving
D)water photolysis
E)cytochrome b₆/f

Question 12

Following photolysis, the resulting protons are released into the ______, contributing to the proton gradient across the ______ membrane.

A)lumen of the thylakoid; thylakoid
B)chloroplast stroma; outer chloroplast
C)chloroplast stroma; thylakoid
D)chloroplast matrix; inner chloroplast
E)cytosol; inner mitochondrial

Question 13

Which of the following statements about the electromagnetic spectrum is FALSE?

A)All radiations travel in waves.
B)White light consists of a number of different colors.
C)Different colors of light are refracted at different angles.
D)A wavelength is the distance from one wave crest to the crest of another.
E)The longer the wavelength of light, the more energy it has.

Question 14

In photophosphorylation, the role of the ATP synthase complex is to provide a channel for protons to flow back into the:

A)lumen of the thylakoid.
B)chloroplast stroma.
C)intermembrane space of the mitochondrion.
D)intermembrane space of the chloroplast.
E)cytosol.

Question 15

Which of the following is the very next event that occurs when a chlorophyll molecule absorbs light?

A)The energy is released as heat.
B)Fluorescence occurs.
C)The electron is boosted to an excited state.
D)Resonance energy transfer occurs.
E)The electron is transferred to an electron transport chain.

Question 16

The energy-transduction reactions of photosynthesis are also called the ______ reactions.

A)light
B)dark
C)light-independent
D)carbon-fixation
E)biosynthetic

Question 17

In contrast to Photosystem I, Photosystem II is located primarily:

A)in the chloroplast.
B)in the cytosol.
C)in grana thylakoids.
D)in stroma thylokoids
E)in the plasma membrane.

Question 18

F.Blackman showed that:

A)air "restored" by vegetation could support the breathing of animals.
B)air is "restored" only in the presence of light and only by the green parts of the plant.
C)photosynthesis has a light-dependent stage and a light-independent stage.
D)isolated chloroplasts are able to produce O₂ in the absence of light.
E)all the substance of a plant is provided by water and not the soil.

Question 19

Chlorophyll absorbs light principally in the ______ wavelengths.

A)blue and green
B)green and violet
C)blue and violet
D)violet and green
E)green and red

Question 20

An action spectrum is different from an absorption spectrum in that an action spectrum:

A)provides evidence that a particular pigment is responsible for a particular process.
B)provides information about the extent of reflectance.
C)is the light-transmitting pattern of a pigment.
D)is the light-absorbing pattern of a pigment.
E)is the relative effectiveness of different wavelengths for a specific process.

Question 21

Which of the following is a C₄ plant?

A)rice
B)oats
C)Kentucky bluegrass
D)crabgrass
E)wheat

Question 22

The malate or aspartate produced in the C₄ pathway moves next into:

A)the bundle-sheath cells.
B)the mesophyll cells.
C)the stomata.
D)Photosystem I.
E)Photosystem II.

Question 23

Rubisco can use ______ or CO₂ as a substrate.

A)3-phosphoglycerate
B)O₂
C)glyceraldehyde 3-phosphate
D)serine
E)oxaloacetate

Question 24

Carbon dioxide is "fixed" by bonding to:

A)glyceraldehyde 3-phosphate.
B)3-phosphoglycerate.
C)ribulose 1,5-bisphosphate.
D)NADP⁺.
E)ADP.

Question 25

Kranz anatomy is characterized by a layer of ____ around a layer of ____.

A)xylem cells; mesophyll cells
B)mesophyll cells; bundle-sheath cells
C)mesophyll cells; phloem cells
D)bundle-sheath cells; phloem cells
E)bundle-sheath cells; mesophyll cells

Question 26

Which of the following does NOT occur in the Calvin cycle?

A)ATP is hydrolyzed.
B)ADP is phosphorylated to ATP.
C)NADPH is oxidized.
D)Ribulose 1,5-bisphosphate is regenerated.
E)CO₂ is fixed.

Question 27

In the C₄ pathway, the enzyme PEP carboxylase:

A)uses O₂ as a substrate.
B)uses CO₂ as a substrate.
C)operates inefficiently when the CO₂ concentration is low.
D)is active only in the chloroplasts of mesophyll cells.
E)catalyzes the formation of oxaloacetate.

Question 28

How many molecules of CO₂ are fixed during each turn of the Calvin cycle?

A)one
B)two
C)three
D)four
E)five

Question 29

Suaeda aralocaspica is different from many other C₄ plants because it:

A)has only one type of chloroplast.
B)has Kranz anatomy.
C)lacks Kranz anatomy.
D)has bundle-sheath cells.
E)lacks bundle-sheath cells.

Question 30

During cyclic electron flow, electrons are transferred directly from P₇₀₀ to A_o to:

A)P₇₀₀.
B)P₆₈₀.
C)the photosynthetic electron transport chain.
D)the photosynthetic ATP synthase.
E)the lumen of the thylakoid.

Question 31

One of the benefits of photorespiration is removing toxic:

A)3-phosphoglyceraldehyde.
B)phosphoglycolate.
C)ribulose-bisphosphate.
D)3-phosphoglycerate.
E)oxaloacetate.

Question 32

Which of the following statements about photorespiration is FALSE?

A)It yields ATP but not NADPH.
B)Phosphoglycolate is an intermediate.
C)It consumes oxygen and releases CO₂.
D)It is a wasteful process.
E)Three cellular organelles participate in the process.

Question 33

The Calvin cycle takes place in the:

A)lumen of the thylakoid.
B)chloroplast stroma.
C)thylakoid membrane.
D)cytoplasm.
E)mitochondrial matrix.

Question 34

Which of the following conditions favors photorespiration?

A)a ratio of CO₂ to O₂ that favors CO₂
B)conditions that cause the stomata to open
C)plants growing far apart
D)a hot, dry environment
E)darkness

Question 35

Compared with a C₃ plant, a C₄ plant:

A)carries out more photorespiration.
B)has a lower photosynthetic efficiency.
C)has more Rubisco.
D)has a higher leaf nitrogen content.
E)needs more ATP to fix CO₂.

Question 36

Which of the following is produced during noncyclic AND cyclic electron flow?

A)water
B)NADPH
C)sugar
D)ATP
E)O₂

Question 37

Most of the glyceraldehyde 3-phosphate not exported to the cytosol is converted to ______ and stored in the chloroplasts.

A)3-phosphoglycerate
B)sucrose
C)glucose
D)starch
E)ribulose 1,5-bisphosphate

Question 38

Which of the following statements concerning ferredoxin is FALSE?

A)It is the final electron acceptor of Photosystem I.
B)It is found in the chloroplast grana.
C)It transfers electrons to NADP⁺.
D)It is an iron-sulfur protein.
E)It is a mobile protein.

Question 39

Which of the following statements about the Calvin cycle is FALSE?

A)It requires more ATP than NADPH.
B)Each reaction is catalyzed by a specific enzyme.
C)It regenerates ribulose 1,5-bisphosphate.
D)It fixes CO₂.
E)It uses ATP from noncyclic, but not cyclic, photophosphorylation.

Question 40

The role of Rubisco is to catalyze the conversion of:

A)CO₂ to an unstable six-carbon compound.
B)CO₂ to glyceraldehyde 3-phosphate.
C)3-phosphoglycerate to glyceraldehyde 3-phosphate.
D)glyceraldehyde 3-phosphate to sucrose.
E)glyceraldehyde 3-phosphate to starch.

Question 41

Which of the following is most likely to occur in a leaf cell of a CAM plant during the day?

A)entry of CO₂ through stomata
B)exit of water through stomata
C)decarboxylation of malic acid
D)fixation of CO₂ by PEP carboxylase
E)conversion of oxaloacetate to malate

Question 42

Which of the following statements about CAM plants is FALSE?

A)Not all CAM plants are succulent.
B)All CAM plants are flowering plants.
C)They use both C₃ and C₄ pathways.
D)They are dependent on nighttime accumulation of CO₂ for photosynthesis.
E)Their water-use efficiency is higher than that of C₃ and C₄ plants.
True-False Questions

Question 43

The light-harvesting complex contains does not contain a reaction center.

Question 44

The ATP and NADPH generated by the light reactions are used in the Calvin cycle.

Question 45

All photosynthetic eukaryotes contain both chlorophylls a and b.

Question 46

The cytochrome b₆/f complex links Photosystems II and I.

Question 47

In Photosystem II, pheophytin passes an electron directly to plastoquinone.

Question 48

Phycobilins are water-soluble accessory pigments found in cyanobacteria and red algae.

Question 49

Compared with C₃ plants, C₄ plants:

A)are well adapted to low light intensities.
B)are well adapted to low temperatures.
C)are well adapted to moist areas.
D)use nitrogen more efficiently.
E)fix CO₂ less efficiently.

Question 50

Which of the following is not considered a CAM plant?

A)cactus
B)pineapple
C)Spanish "moss"
D)Welwitschia
E)wheat

Question 51

The energy of a photon of light is directly proportional to its wavelength.

Question 52

The photolysis of water occurs in conjunction with Photosystem II but not Photosystem I.

Question 53

Chlorophyll absorbs light principally in the green wavelength.

Question 54

In CAM plants, malate formed as the end product of CO₂ fixation in the dark is stored as malic acid in the:

A)vacuole.
B)chloroplast stroma.
C)thylakoid lumen.
D)cytosol.
E)nucleus.

Question 55

At the reaction center of Photosystem II is P₇₀₀.

Question 56

B.van Neil's experiments provided evidence that water, not carbon dioxide, was the source of the oxygen in photosynthesis.

Question 57

In the process of cyclic photophosphorylation, both ATP and NADPH are produced.

Question 58

An action spectrum can be used to demonstrate the relative effectiveness of different wavelengths of light for photosynthesis.

Question 59

Protons flow through the ATP synthesis from the stroma into the thylakoid lumen.

Question 60

Accessory pigments are directly involved in the energy-transduction processes of photosynthesis.

Question 61

One of the benefits of photorespiration is to remove phosphoglycolate from the plant.

Question 62

C₃-C₄ intermediates provide evidence for the evolution of C₃ plants from C₄ ancestors.

Question 63

The leaf anatomy of C₄ plants provides a spatial separation between the C₄ pathway and the Calvin cycle.

Question 64

The concentration of CO₂ in the Earth's atmosphere is approximately 3 percent.

Question 65

Rubisco can use either O₂ or CO₂ as a substrate.

Question 66

Some CAM plants can keep their stomata closed night and day.

Question 67

Photorespiration is an energetically wasteful process that seldom occurs in nature.