Deck 8: Photosynthesis

Question 1

If photosynthesizing green algae are provided with CO₂ containing heavy oxygen (18O), subsequent analysis will show that 18O is absent from which of the following molecules produced by the algae?

A) O₂
B) glyceraldehyde 3-phosphate (G3P)
C) glucose
D) ribulose bisphosphate (RuBP)

Answer 1

A

Question 2

In autotrophic bacteria, where are chlorophyll-like pigments located?

A) in the chloroplast membranes
B) in the chloroplast stroma
C) in infolded regions of the plasma membrane
D) in infolded regions of the cell wall
E) in the central vacuole membrane

Answer 2

C

Question 3

Which of the following events occurs in the light reactions of photosynthesis?

A) NADP+ is produced.
B) ATP is consumed to yield ADP.
C) Carbon dioxide is fixed in organic molecules.
D) Light is absorbed and funneled to reaction-center chlorophyll a.

Answer 3

D

Question 4

If plants are grown in the light with CO₂ containing heavy oxygen (18O), subsequent analysis will show that 18O incorporated in organic molecules first appears in

A) the thylakoid space.
B) the thylakoid membranes.
C) the stroma.
D) photosystem II
E) the chloroplast intermembrane space.

Question 5

If plants are grown with H₂O containing heavy oxygen (18O), subsequent analysis will show that 18O first appears in which of the following molecules produced by the algae?

A) O₂
B) glyceraldehyde 3-phosphate (G3P)
C) glucose
D) ribulose bisphosphate (RuBP)
E) CO₂

Question 6

A plant has a unique photosynthetic pigment. The leaves of this plant appear to be reddish yellow. What wavelengths of visible light are being absorbed by this pigment?

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

Question 7

What does the chemiosmotic process in chloroplasts involve?

A) establishment of a proton gradient across the thylakoid membrane
B) diffusion of electrons through the thylakoid membrane
C) reduction of water to produce oxygen
D) formation of glucose, using carbon dioxide, NADPH, and ATP

Question 8

In the thylakoid membranes, what is the main role of the pigment molecules in a light-harvesting complex?

A) split water and release oxygen to the reaction-center chlorophyll
B) transfer light energy to the reaction-center chlorophyll
C) synthesize ATP from ADP and ℗i
D) transfer electrons to NADPH

Question 9

What is the primary function of cyclic electron flow?

A) to produce additional NADPH
B) to produce additional ATP
C) to produce additional oxygen
D) to produce additional carbon dioxide

Question 10

Some photosynthetic organisms contain chloroplasts that lack photosystem II, yet are able to survive. The best way to detect the lack of photosystem II in these organisms would be

A) to determine if they have thylakoids in the chloroplasts.
B) to test for liberation of O₂ in the light.
C) to test for CO₂ fixation in the dark.
D) to the action spectrum for photosynthesis.

Question 11

Where does the Calvin cycle take place?

A) stroma of the chloroplast
B) thylakoid membrane
C) outer membrane of the chloroplast
D) interior of the thylakoid (thylakoid space)

Question 12

What are the products of linear electron flow?

A) heat and fluorescence
B) ATP and water
C) ATP and NADPH
D) ADP and NADP+

Question 13

Which of the following activities is associated with photosystem II?

A) Light energy excites electrons in the thylakoid membrane electron transport chain.
B) Electrons released from the P680 chlorophyll are replaced by electrons derived from water.
C) The P680 chlorophyll donates a pair of electrons directly to NADP+, producing NADPH.
D) Electrons are passed from the P680 chlorophyll to molecular oxygen (O₂).

Question 14

In chemiosmosis in mitochondria, protons flow from the intermembrane space into the matrix, whereas in chemiosmosis in chloroplasts, protons flow from

A) the stroma into the cytosol.
B) the matrix into the stroma.
C) the stroma into the thylakoid space.
D) the intermembrane space into the stroma.
E) the thylakoid space to into the stroma.

Question 15

As a research scientist, you measure the amount of ATP and NADPH consumed by the Calvin cycle in 1 hour. You find 30,000 molecules of ATP consumed, but only 20,000 molecules of NADPH. What is the source of the extra ATP?

A) photosystem II
B) photosystem I
C) cyclic electron flow
D) linear electron flow

Question 16

Suppose the interior of the thylakoids of isolated chloroplasts were made acidic and then transferred in the dark to a pH 8 solution. What would be likely to happen?

A) The isolated chloroplasts will produce ATP.
B) The isolated chloroplasts will make glucose.
C) Cyclic photophosphorylation will occur.
D) The isolated chloroplasts will generate oxygen gas.
E) The isolated chloroplasts will reduce NADP+ to NADPH.

Question 17

Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?

A) CO₂ and glucose
B) H₂O and O₂
C) ADP, ℗i, and NADP+
D) electrons and H+
E) ATP and NADPH

Question 18

If photosynthesizing green algae are provided with CO₂ containing heavy oxygen (18O), subsequent analysis will show that 18O first appears in which of the following molecules produced by the algae?

A) O₂
B) glyceraldehyde 3-phosphate (G3P)
C) glucose
D) ribulose bisphosphate (RuBP)
E) 3-phosphoglycerate

Question 19

Which of the following is directly associated with photosystem I?

A) harvesting of light energy by ATP
B) receiving electrons from the thylakoid membrane electron transport chain
C) generation of molecular oxygen
D) extraction of hydrogen electrons from the splitting of water

Question 20

When oxygen is released as a result of photosynthesis, it is a direct by-product of

A) reducing NADP+.
B) splitting water molecules.
C) chemiosmosis.
D) electron transfer in photosystem I.
E) electron transfer in photosystem II.

Question 21

Reduced soluble electron carriers are produced in

A) the light reactions of photosynthesis.
B) the Calvin cycle.
C) the citric acid cycle.
D) both the Calvin cycle and the citric acid cycle.
E) both the light reactions of photosynthesis and the citric acid cycle.

Question 22

The pH of the inner thylakoid space has been measured, as have the pH of the stroma and of the cytosol of a particular plant cell. Which, if any, relationship would you expect to find?

A) The pH within the thylakoid is lower than that of the stroma.
B) The pH of the stroma is lower than that of either the thylakoid space or cytosol.
C) The pH of the thylakoid space is higher than that of either the stroma or cytosol.
D) The pH of the stroma is higher than that of either the thylakoid space or cytosol.

Question 23

Some photosynthetic bacteria (e.g., purple sulfur bacteria) have only photosystem I, whereas others (e.g., cyanobacteria) have both photosystem I and photosystem II. Which of the following might this observation imply?

A) Photosystem II was selected against in some species.
B) Photosynthesis with only photosystem I is more ancestral.
C) Photosystem II may have evolved to be more photoprotective.
D) Linear electron flow is more primitive than cyclic flow of electrons.
E) Cyclic electron flow is essential to photosynthesis.

Question 24

What is the primary function of the Calvin cycle?

A) regenerate ATP for use in the light reactions of photosynthesis
B) produce carbon dioxide for use in the light reactions of photosynthesis
C) produce oxygen by oxidizing water
D) produce simple sugars from carbon dioxide

Question 25

What is the relationship between wavelength of light and the quantity of energy per photon?

A) They have a direct, linear relationship.
B) They are inversely related.
C) They are logarithmically related.
D) They are only related in certain parts of the spectrum.

Question 26

A flask containing photosynthetic green algae and a control flask containing water with no algae are both placed under a bank of lights, which are set to cycle between 12 hours of light and 12 hours of dark. The dissolved oxygen concentrations in both flasks are monitored. Predict what the relative dissolved oxygen concentrations will be in the flask with algae compared to the control flask.

A) The concentration of dissolved oxygen in the flask with algae will always be higher.
B) The concentration of dissolved oxygen in the flask with algae will always be lower.
C) The concentration of dissolved oxygen in the flask with algae will be higher in the light, but the same in the dark.
D) The concentration of dissolved oxygen in the flask with algae will be higher in the light, but lower in the dark.
E) The concentration of dissolved oxygen in the flask with algae will be lower in the light, but higher in the dark.

Question 27

The splitting of carbon dioxide to form oxygen gas and carbon compounds occurs during

A) photosynthesis.
B) respiration.
C) both photosynthesis and cellular respiration.
D) neither photosynthesis nor respiration.
E) photorespiration.

Question 28

Which of the following statements about the relationship between photosynthesis and cellular respiration is true?

A) In cellular respiration the biochemical pathways of photosynthesis run in reverse.
B) In photosynthesis the biochemical pathways of cellular respiration run in reverse.
C) Cellular respiration occurs only in animals and photosynthesis occurs only in plants.
D) There is a net consumption of ATP in cellular respiration and a net production of ATP in photosynthesis.
E) Cellular respiration is catabolic and photosynthesis is anabolic.

Question 29

In photosynthetic cells, synthesis of ATP by chemiosmosis occurs during

A) photosynthesis only.
B) cellular respiration only.
C) both photosynthesis and cellular respiration.
D) photophosphorylation only.

Question 30

Carotenoids are often found in foods that are considered to have antioxidant properties in human nutrition. What related function do they have in plants?

A) They are accessory pigments that narrow the spectrum of light wavelengths used to drive photosynthesis.
B) They absorb harmful ultraviolet radiation to protect plant chromosomes from damage.
C) They protect against oxidative damage from excessive light energy.
D) They absorb orange light, enhancing the efficiency of photosynthesis.

Question 31

Electron transport chains associated with ATP production in plant cells are located in

A) the outer chloroplast membranes only.
B) the thylakoid membranes only.
C) the mitochondrial inner membranes only.
D) the thylakoid and outer chloroplast membranes.
E) the thylakoid and mitochondrial inner membranes.

Question 32

P680+ is said to be the strongest biological oxidizing agent. Given its function, why is this necessary?

A) It is the receptor for the most excited electrons in either photosystem.
B) It is the molecule that transfers electrons to the photosynthetic electron transport chain.
C) It transfers its electrons directly to NADP+ to produce NADPH.
D) It obtains electrons from the oxygen atom in a water molecule, so it must have a stronger affinity for electrons than oxygen has.
E) It has a positive charge.

Question 33

In which types of plants is the enzyme rubisco found?

A) C3 plants only
B) C4 plants only
C) C3 and C4 plants only
D) C4 and CAM plants only
E) C3, C4, and CAM plants

Question 34

Generation of proton gradients across membranes occurs during

A) photosynthesis only.
B) cellular respiration only.
C) both photosynthesis and cellular respiration.
D) neither photosynthesis nor cellular respiration.

Question 35

In mitochondria, the electron transport chain pumps protons from the matrix into the intermembrane space, whereas in chloroplasts, the electron transport chain pumps protons from

A) the stroma to the cytosol.
B) the matrix to the stroma.
C) the stroma to the thylakoid space.
D) the intermembrane space to the stroma.
E) the thylakoid space to the stroma.

Question 36

In the process of carbon fixation, three molecules of RuBP combine with three molecules of CO₂ to produce three six-carbon molecules, which are then split to produce 12 molecules of 3-phosphoglycerate. After phosphorylation and reduction produce 12 glyceraldehyde 3-phosphate (G3P), what more needs to happen to complete the Calvin cycle?

A) release of two G3P to make sugars and regeneration of ATP from ADP
B) release of two G3P to make sugars and regeneration of RuBP
C) release of one G3P to make sugars and regeneration of NADPH
D) release of one G3P to make sugars and regeneration of citrate
E) release of one G3P to make sugars and regeneration of RuBP

Question 37

In a plant cell, where are ATP synthase complexes located?

A) thylakoid membranes only
B) plasma membrane only
C) inner mitochondrial membranes only
D) thylakoid membrane and inner mitochondrial membranes
E) thylakoid membrane and plasma membranes

Question 38

A reduction in the amount of NADP+ available in plant cells in the light will ultimately result in

A) an increase in the rate of the Calvin cycle.
B) a decrease in the rate of linear electron flow.
C) a decrease in the rate of cyclic electron flow.
D) an increase in the rate of oxygen production.

Question 39

Reduction of oxygen to form water occurs during

A) the light reactions of photosynthesis only.
B) the Calvin cycle only.
C) cellular respiration only.
D) both the light reactions of photosynthesis and cellular respiration.
E) both the light reactions of photosynthesis and the Calvin cycle.

Question 40

Where are the molecules of the electron transport chain associated with photophosphorylation located in plant cells?

A) thylakoid membranes of chloroplasts
B) stroma of chloroplasts
C) outer membrane of chloroplasts
D) matrix of mitochondria
E) inner membrane of mitochondria

Question 41

Where do the enzymatic reactions of the Calvin cycle take place?

A) stroma of the chloroplast
B) thylakoid membranes
C) matrix of the mitochondria
D) thylakoid space

Question 42

Figure 8.1
Figure 8.1 shows the absorption spectrum for chlorophyll a and the action spectrum for photosynthesis. Why are they different?

A) Green and yellow wavelengths inhibit the absorption of red and blue wavelengths.
B) Bright sunlight destroys photosynthetic pigments.
C) Oxygen given off during photosynthesis interferes with the absorption of light.
D) Other pigments absorb light in addition to chlorophyll a.

Question 43

Please use the following information to answer the question(s) below.
Theodor W. Engelmann illuminated a filament of algae with light that passed through a prism, thus exposing different segments of algae to different wavelengths of light. He added aerobic bacteria and then noted in which areas the bacteria congregated. He found that the largest groups were found in the areas illuminated by the red and blue light.
What did Engelmann conclude about the congregation of bacteria in the red and blue areas?

A) Bacteria congregated in these areas due to a local increase in temperature generated by illumination by red and blue light.
B) Bacteria released excess carbon dioxide in these areas.
C) Bacteria congregated in these areas because they are attracted to red and blue light.
D) Bacteria congregated in these areas because they were the areas where the most oxygen was released by the algae.
E) Bacteria congregated in these areas because green, yellow, and orange light inhibits bacterial metabolism.

Question 44

Photorespiration occurs when rubisco combines RuBP with

A) CO₂.
B) O₂.
C) glyceraldehyde 3-phosphate.
D) citrate.
E) NADPH.

Question 45

Figure 8.2
Use Figure 8.2 and the compounds labeled A, B, C, D, and E to answer the following question. If the carbon atom of each of the incoming CO₂ molecules is labeled with a radioactive isotope of carbon, which organic molecules of the Calvin cycle will be radioactively labeled after one cycle?

A) C only
B) B, C, D, and E
C) C, D, and E only
D) B and C only
E) B and D only

Question 46

Figure 8.2
Use Figure 8.2 and the compounds labeled A, B, C, D, and E to answer the following question. If ATP used by this plant is labeled with radioactive phosphorus, which molecule or molecules of the Calvin cycle will be radioactively labeled first?

A) B only
B) B and C only
C) B, C, and D only
D) B and E only
E) B and D only

Question 47

Which of the following statements best represents the relationships between the light reactions and the Calvin cycle?

A) The light reactions provide ATP and NADPH to the Calvin cycle, and the Calvin cycle returns ADP, ℗i, and NADP+ to the light reactions.
B) The light reactions provide ATP and NADPH to the carbon fixation step of the Calvin cycle, and the Calvin cycle provides water and electrons to the light reactions.
C) The light reactions supply the Calvin cycle with CO₂ to produce sugars, and the Calvin cycle supplies the light reactions with sugars to produce ATP.
D) The light reactions provide the Calvin cycle with oxygen for carbon fixation, and the Calvin cycle provides the light reactions with sugars to produce ATP.

Question 48

CAM plants keep stomata closed in daytime, thus reducing loss of water. They can do this because they

A) fix CO₂ into organic acids during the night when temperatures are cooler.
B) fix CO₂ into organic acids in the bundle-sheath cells, which do not rely on stomata.
C) fix CO₂ into organic acids in the mesophyll cells, which do not rely on stomata.
D) fix CO₂ into by combining it with RuBP in the Calvin cycle.
E) obtain CO₂ through their roots during the day.

Question 49

Reactions that consume CO₂ take place in

A) the light reactions of photosynthesis only.
B) the Calvin cycle only.
C) the citric acid cycle only.
D) both the light reactions and the Calvin cycle.
E) both the Calvin cycle and the citric acid cycle.

Question 50

Compared to C3 plants, C4 plants

A) can continue to fix CO₂ even at relatively low CO₂ concentrations and high oxygen concentrations.
B) have higher rates of photorespiration.
C) do not use rubisco for carbon fixation.
D) grow better under cool, moist conditions.

Question 51

The NADPH required for the Calvin cycle comes from

A) reactions initiated in photosystem I.
B) reactions initiated in photosystem II.
C) the citric acid cycle.
D) glycolysis.
E) oxidative phosphorylation.

Question 52

In C3 photosynthesis, the reactions that require ATP take place in

A) the light reactions alone.
B) the Calvin cycle alone.
C) both the light reactions and the Calvin cycle.
D) neither the light reactions nor the Calvin cycle.

Question 53

Why are C4 plants able to photosynthesize with no apparent photorespiration?

A) They do not participate in the Calvin cycle.
B) They keep their stomata open most of the time in hot, dry climates, which allows for water loss to prevent photorespiration.
C) They keep their stomata closed most of the time in hot, dry climates, which conserves water and oxygen to inhibit photorespiration.
D) They do not use rubisco to fix CO₂.
E) They exclude oxygen from their tissues.

Question 54

What compound provides the reducing power for the Calvin cycle reactions?

A) ATP
B) FAD
C) FADH₂
D) NADPH
E) CO₂

Question 55

Figure 8.1
Figure 8.1 shows the absorption spectrum for chlorophyll a and the action spectrum for photosynthesis. What colors of light are least effective in driving photosynthesis?

A) violet-blue
B) green-yellow
C) yellow-orange
D) orange-red

Question 56

What would be the expected effect on plants if the atmospheric CO₂ concentration was doubled?

A) All plants will experience increased rates of photosynthesis.
B) C3 plants will have faster growth; C4 plants will be minimally affected.
C) C4 plants will have faster growth; C3 plants will be minimally affected.
D) C3 plants will have faster growth; C4 plants will have slower growth.

Question 57

Figure 8.1
Figure 8.1 shows the absorption spectrum for chlorophyll a and the action spectrum for photosynthesis. What wavelength of light is most effective in driving photosynthesis?

A) 420 nm
B) 450 nm
C) 500 nm
D) 650 nm
E) 700 nm

Question 58

Figure 8.2
To identify the molecule that accepts CO₂, Calvin and Benson manipulated the carbon-fixation cycle by either cutting off CO₂ or cutting off light from cultures of photosynthetic algae. They then measured the concentrations of various metabolites immediately following the manipulation. How would these experiments help identify the CO₂ acceptor? Study Figure 8.2 to help you in determining the correct answer.

A) The CO₂ acceptor concentration would decrease when either the CO₂ or light is cut off.
B) The CO₂ acceptor concentration would increase when either the CO₂ or light is cut off.
C) The CO₂ acceptor concentration would increase when the CO₂ is cut off, but decrease when the light is cut off.
D) The CO₂ acceptor concentration would decrease when the CO₂ is cut off, but increase when the light is cut off.
E) The CO₂ acceptor concentration would stay the same regardless of the CO₂ or light.

Question 59

Figure 8.2
Use Figure 8.2 and the compounds labeled A, B, C, D, and E to answer the following question. Which molecule(s) of the Calvin cycle is (are) also found in glycolysis?

A) B, C, E, and 3-phosphoglycerate
B) B, C, and E only
C) 3-phosphoglycerate only
D) B, C, D, and 3-phosphoglycerate only
E) E only

Question 60

Photorespiration lowers the efficiency of photosynthesis by

A) consuming excess carbon dioxide.
B) reducing the amount of water consumed.
C) reducing the amount of sugar produced.
D) producing excess ATP, but less NADPH.
E) inhibiting electron transfers from photosystem II.

Question 61

Please use the following information to answer the question(s) below.
A spaceship is designed to support animal life for a multiyear voyage to the outer planets of the solar system. Plants will be grown to provide oxygen and to recycle carbon dioxide. Because the spaceship will be too far from the sun for photosynthesis, an artificial light source will be needed.
Halobacterium has a photosynthetic membrane that appears purple. Its photosynthetic action spectrum is the inverse of the action spectrum for green plants. (That is, the Halobacterium action spectrum has a peak where the green plant action spectrum has a trough.) What wavelengths of light do the Halobacterium photosynthetic pigments absorb?

A) red and yellow
B) blue, green, and red
C) green and yellow
D) red and green
E) blue and red

Question 62

The light reactions of photosynthesis supply the Calvin cycle with

A) light energy.
B) C and ATP.
C) O₂ and NADPH.
D) ATP and NADPH.

Question 63

Which process is most directly driven by light energy?

A) creation of a pH gradient by pumping protons across the thylakoid membrane
B) reduction of NADP+ molecules
C) removal of electrons from chlorophyll molecules
D) ATP synthesis

Question 64

Which of the following statements is a correct distinction between autotrophs and heterotrophs?

A) Autotrophs, but not heterotrophs, can nourish themselves beginning with CO₂ and other nutrients that are inorganic.
B) Only heterotrophs require chemical compounds from the environment.
C) Cellular respiration is unique to heterotrophs.
D) Only heterotrophs have mitochondria.

Question 65

Which of the following does not occur during the Calvin cycle?

A) carbon fixation
B) oxidation of NADPH
C) release of oxygen
D) regeneration of the CO₂ acceptor

Question 66

How is photosynthesis similar in C4 plants and CAM plants?

A) In both cases, electron transport is not used.
B) Both types of plants make sugar without the Calvin cycle.
C) In both cases, rubisco is not used to fix carbon initially.
D) Both types of plants make most of their sugar in the dark.

Question 67

Please use the following information to answer the question(s) below.
A spaceship is designed to support animal life for a multiyear voyage to the outer planets of the solar system. Plants will be grown to provide oxygen and to recycle carbon dioxide. Because the spaceship will be too far from the sun for photosynthesis, an artificial light source will be needed.
What wavelengths of light should be used to maximize plant growth with a minimum of energy expenditure?

A) full-spectrum white light
B) green light
C) a mixture of blue and red light
D) yellow light
E) UV light

Question 68

In mechanism, photophosphorylation is most similar to

A) substrate-level phosphorylation in glycolysis.
B) oxidative phosphorylation in cellular respiration.
C) carbon fixation.
D) reduction of NADP+.

Question 69

Please use the following information to answer the question(s) below.
A spaceship is designed to support animal life for a multiyear voyage to the outer planets of the solar system. Plants will be grown to provide oxygen and to recycle carbon dioxide. Because the spaceship will be too far from the sun for photosynthesis, an artificial light source will be needed.
A gardener is concerned that her greenhouse is getting too hot from too much light and seeks to shade her plants with colored translucent plastic sheets, the color of which allows passage of only that wavelength. What color should she use to reduce overall light energy, but still maximize plant growth?

A) green
B) blue
C) yellow
D) orange
E) white

Question 70

Please use the following information to answer the question(s) below.
Theodor W. Engelmann illuminated a filament of algae with light that passed through a prism, thus exposing different segments of algae to different wavelengths of light. He added aerobic bacteria and then noted in which areas the bacteria congregated. He found that the largest groups were found in the areas illuminated by the red and blue light.
What would you predict would happen if you ran the same experiment without passing light through a prism?

A) The bacteria would congregate toward the middle of the algal filament.
B) The bacteria would be relatively evenly distributed along the algal filament.
C) The number of bacteria present would decrease due to an increase in the carbon dioxide concentration.
D) The number of bacteria present would increase due to an increase in the carbon dioxide concentration.
E) The number of bacteria would decrease due to a decrease in the temperature along the length of the algal filament.

Question 71

Please use the following information to answer the question(s) below.
Theodor W. Engelmann illuminated a filament of algae with light that passed through a prism, thus exposing different segments of algae to different wavelengths of light. He added aerobic bacteria and then noted in which areas the bacteria congregated. He found that the largest groups were found in the areas illuminated by the red and blue light.
An outcome of this experiment was to help determine the relationship between

A) heterotrophic and autotrophic organisms.
B) wavelengths of light and the rate of aerobic respiration.
C) wavelengths of light and the amount of heat released.
D) wavelengths of light and the rate of photosynthesis.
E) the concentration of carbon dioxide and the rate of photosynthesis.

Question 72

Which of the following sequences correctly represents the flow of electrons during photosynthesis?

A) NADPH → O₂ → CO₂
B) H₂O → NADPH → Calvin cycle
C) H₂O → photosystem I → photosystem II
D) NADPH → electron transport chain → O₂