Deck 8: Photosynthesis

Question 1

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

Answer 1

B

Question 2

Which of the following are 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
E) passing electrons to the thylakoid membrane electron transport chain

Answer 2

B

Question 3

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 ferredoxin and then NADPH
E) concentrate photons within the stroma

Answer 3

B

Question 4

Which statement describes the functioning of photosystem II?

A) Light energy excites electrons in the thylakoid membrane electron transport chain.
B) Photons are passed along to a reaction-center chlorophyll.
C) The P680 chlorophyll donates a pair of protons to NADP+, which is thus converted to NADPH.
D) The electron vacancies in P680+ are filled by electrons derived from water.
E) The splitting of water yields molecular carbon dioxide as a by-product.

Question 5

What are the products of linear electron flow?

A) heat and fluorescence
B) ATP and P700
C) ATP and NADPH
D) ADP and NADP+
E) P700 and P680

Question 6

If photosynthesizing green algae are provided with CO2 containing heavy oxygen (18O), later analysis will show that all of the following molecules produced by the algae contain 18O except

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

Question 7

In autotrophic bacteria, where is chlorophyll located?

A) in chloroplast membranes
B) in chloroplast stroma
C) in the ribosomes
D) in the nucleoid
E) in the infolded plasma membrane

Question 8

Where are the molecules of the electron transport chain found in plant cells?

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

Question 9

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 10

In any ecosystem, terrestrial or aquatic, which of the following are always necessary?

A) autotrophs and heterotrophs
B) producers and primary consumers
C) photosynthesizers
D) autotrophs
E) green plants

Question 11

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 ATP energy
D) movement of water by osmosis into the thylakoid space from the stroma
E) formation of glucose, using carbon dioxide, NADPH, and ATP

Question 12

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

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

Question 13

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

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

Question 14

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

A) NADP is produced.
B) NADPH is reduced to NADP+.
C) Carbon dioxide is incorporated into PGA.
D) ATP is phosphorylated to yield ADP.
E) Light is absorbed and funneled to reaction-center chlorophyll a.

Question 15

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 do experiments to generate an action spectrum.
E) to test for production of either sucrose or starch.

Question 16

Which of the following statements best describes the relationship between photosynthesis and respiration?

A) Respiration runs the biochemical pathways of photosynthesis in reverse.
B) Photosynthesis stores energy in complex organic molecules, whereas respiration releases it.
C) Photosynthesis occurs only in plants and respiration occurs only in animals.
D) ATP molecules are produced in photosynthesis and used up in respiration.
E) Respiration is anabolic and photosynthesis is catabolic.

Question 17

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. Where did the extra ATP molecules come from?

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

Question 18

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) the electron transfer system of photosystem I.
E) the electron transfer system of photosystem II.

Question 19

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 make ATP.
B) The Calvin cycle will be activated.
C) Cyclic photophosphorylation will occur.
D) The isolated chloroplasts will generate oxygen gas.
E) The isolated chloroplasts will reduce NADP+ to NADPH.

Question 20

Where does the Calvin cycle take place?

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

Question 21

In thylakoids, protons travel through ATP synthase from the thylakoid space to the stroma. Therefore, the catalytic "knobs" of ATP synthase would be located

A) on the side facing the thylakoid space.
B) on the ATP molecules themselves.
C) on the pigment molecules of photosystem I and photosystem II.
D) on the stromal side of the membrane.
E) built into the center of the thylakoid stack (granum).

Question 22

Reduction of oxygen to form water occurs during

A) photosynthesis only.
B) respiration only.
C) both photosynthesis and respiration.
D) neither photosynthesis nor respiration.
E) the dark reactions only.

Question 23

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

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

Question 24

Reduction of NADP+ occurs during

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

Question 25

In metabolic processes of cell respiration and photosynthesis, prosthetic groups such as heme and iron-sulfur complexes are encountered in components of the electron transport chain. What do they do?

A) donate electrons
B) act as reducing agents
C) act as oxidizing agents
D) transport protons within the mitochondria and chloroplasts
E) both oxidize and reduce during electron transport

Question 26

What is the primary function of the Calvin cycle?

A) use ATP to release carbon dioxide
B) use NADPH to release carbon dioxide
C) split water and release oxygen
D) transport RuBP out of the chloroplast
E) synthesize simple sugars from carbon dioxide

Question 27

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.
E) the chloroplast, but are not part of photosynthesis.

Question 28

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.
E) Plant growth will not be affected because atmospheric CO2 concentrations are never limiting for plant growth.

Question 29

In photosynthetic cells, synthesis of ATP by the chemiosmotic mechanism occurs during

A) photosynthesis only.
B) respiration only.
C) both photosynthesis and respiration.
D) neither photosynthesis nor respiration.
E) photorespiration 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 serve as accessory pigments to increase light absorption.
B) They protect against oxidative damage from excessive light energy.
C) They shield the sensitive chromosomes of the plant from harmful ultraviolet radiation.
D) They reflect orange light and enhance red light absorption by chlorophyll.
E) They take up and remove toxins from the groundwater.

Question 31

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 electron in either photosystem.
B) It is the molecule that transfers electrons to plastoquinone (Pq) of the electron transfer system.
C) It transfers its electrons to reduce NADP+ to NADPH.
D) It obtains electrons from the oxygen atom in a water molecule, so it must have a stronger attraction for electrons than oxygen has.
E) It has a positive charge.

Question 32

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 less than that of the stroma.
B) The pH of the stroma is lower than that of the other two measurements.
C) The pH of the stroma is higher than that of the thylakoid space but lower than that of the cytosol.
D) The pH of the thylakoid space is higher than that anywhere else in the cell.
E) There is no consistent relationship.

Question 33

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) cytosol around the chloroplast
E) thylakoid space

Question 34

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 separate phenomena.
E) They are only related in certain parts of the spectrum.

Question 35

Generation of proton gradients across membranes occurs during

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

Question 36

In a cyanobacterium, the reactions that produce NADPH occur 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.
E) the chloroplast, but are not part of photosynthesis.

Question 37

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

A) ATP
B) NAD+
C) NADH
D) NADP+
E) NADPH

Question 38

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 dissolved oxygen in the flask with algae will always be higher.
B) The dissolved oxygen in the flask with algae will always be lower.
C) The dissolved oxygen in the flask with algae will be higher in the light, but the same in the dark.
D) The dissolved oxygen in the flask with algae will be higher in the light, but lower in the dark.
E) The dissolved oxygen in the flask with algae will not be different from the control flask at any time.

Question 39

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 flow is more necessary than linear electron flow.

Question 40

The reactions that produce molecular oxygen (O2) 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.
E) the chloroplast, but are not part of photosynthesis.

Question 41

In the process of carbon fixation, RuBP attaches a CO2 to produce a six-carbon molecule, which is then split to produce two molecules of 3-phosphoglycerate. After phosphorylation and reduction produces glyceraldehyde 3-phosphate (G3P), what more needs to happen to complete the Calvin cycle?

A) addition of a pair of electrons from NADPH
B) inactivation of RuBP carboxylase enzyme
C) regeneration of ATP from ADP
D) regeneration of RuBP
E) regeneration of NADP+

Question 42

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 43

The alternative pathways of photosynthesis using the C4 or CAM systems are said to be compromises. Why?

A) Each one minimizes both water loss and rate of photosynthesis.
B) C4 compromises on water loss and CAM compromises on photorespiration.
C) Both minimize photorespiration but expend more ATP during carbon fixation.
D) CAM plants allow more water loss, whereas C4 plants allow less CO2 into the plant.
E) C4 plants allow less water loss but CAM plants allow more water loss.

Question 44

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.
E) make a four-carbon compound, oxaloacetate, which is then delivered to the citric acid cycle in mitochondria.

Question 45

Reactions that require CO2 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.
E) the chloroplast, but are not part of photosynthesis.

Question 46

The phylogenetic distribution of the enzyme rubisco is limited to

A) C3 plants only.
B) C3 and C4 plants.
C) all photosynthetic eukaryotes.
D) all known photoautotrophs, both bacterial and eukaryotic.
E) all living cells.

Question 47

Use Figure 8.2 and the compounds labeled A, B, C, D, and E to answer the following questions.
Figure 8.2
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, C, D, and E

Question 48

Use Figure 8.2 and the compounds labeled A, B, C, D, and E to answer the following questions.
Figure 8.2
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 49

Photorespiration occurs when rubisco reacts RuBP with

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

Question 50

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 noted 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 51

Figure 8.3
Which of the following statements is true concerning Figure 8.3?

A) It represents cell processes involved in C4 photosynthesis.
B) It represents the type of cell structures found in CAM plants.
C) It represents an adaptation that maximizes photorespiration.
D) It represents a C3 photosynthetic system.
E) It represents a relationship between plant cells that photosynthesize and those that cannot.

Question 52

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 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 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 electron flow, and the Calvin cycle provides the light reactions with water to split.
E) There is no relationship between the light reactions and the Calvin cycle.

Question 53

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.
B) fix CO2 into sugars in the bundle-sheath cells.
C) fix CO2 into pyruvate in the mesophyll cells.
D) use the enzyme phosphofructokinase, which outcompetes rubisco for CO2.
E) use photosystem I and photosystem II at night.

Question 54

Use Figure 8.2 and the compounds labeled A, B, C, D, and E to answer the following questions.
Figure 8.2
If the carbon atom of each of the incoming CO2 molecules is labeled with a radioactive isotope of carbon, which organic molecules 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 55

Photorespiration lowers the efficiency of photosynthesis by

A) consuming carbon dioxide.
B) reducing the amount of 3-phosphoglycerate formed.
C) generating excess ATP.
D) producing ribulose bisphosphate.
E) denaturing rubisco.

Question 56

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

A) They do not participate in the Calvin cycle.
B) They use PEP carboxylase to initially fix CO2.
C) They are adapted to cold, wet climates.
D) They conserve water more efficiently.
E) They exclude oxygen from their tissues.

Question 57

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.
E) Aerobic bacteria take up oxygen, which changes the measurement of the rate of photosynthesis.

Question 58

Use Figure 8.2 and the compounds labeled A, B, C, D, and E to answer the following questions.
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

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 noted 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 released excess carbon dioxide in these areas.
B) Bacteria congregated in these areas due to an increase in the temperature of the red and blue light.
C) Bacteria congregated in these areas because these areas had the most oxygen being released.
D) Bacteria are attracted to red and blue light and thus these wavelengths are more reactive than other wavelengths.
E) Bacteria congregated in these areas due to an increase in the temperature caused by an increase in photosynthesis.

Question 60

Figure 8.1
What wavelength of light in Figure 8.1 is most effective in driving photosynthesis?

A) 420 mm
B) 475 mm
C) 575 mm
D) 625 mm
E) 730 mm

Question 61

Which process is most directly driven by light energy?

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

Question 62

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.
E) In both cases, thylakoids are not involved in photosynthesis.

Question 63

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) Any color will work equally well.

Question 64

In mechanism, photophosphorylation is most similar to

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

Question 65

The light reactions of photosynthesis supply the Calvin cycle with

A) light energy.
B) CO2 and ATP.
C) H2O and NADPH.
D) ATP and NADPH.
E) sugar and O2.

Question 66

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 noted that the largest groups were found in the areas illuminated by the red and blue light.
If you ran the same experiment without passing light through a prism, what would you predict?

A) There would be no difference in results.
B) The bacteria would be relatively evenly distributed along the algal filaments.
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 of the water.

Question 67

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

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

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

Question 69

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
E) consumption of ATP

Question 70

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

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

Question 71

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