Deck 8: Photosynthesis

Question 1

Which of the following molecules 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

Answer 1

E

Question 2

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 transferred to reaction-center chlorophyll.

Answer 2

D

Question 3

The leaves of a plant with a unique photosynthetic pigment appear orange in sunlight.What wavelengths of visible light are most likely absorbed by this unique pigment?

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

Answer 3

B

Question 4

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 5

The Calvin cycle in a culture of algae grown in the light utilizes approximately 30,000 molecules of ATP but only 20,000 molecules of NADPH per hour.What is the source of the extra ATP utilized?

A)photosystem II
B)photosystem I
C)cyclic electron flow
D)oxidation of NADPH

Question 6

A reduction in the amount of NADP⁺ available in plant cells in the light will ultimately result in which of the following effects?

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 7

Which of the following reactions reduce(s)oxygen to form water?

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 8

In chemiosmosis in mitochondria,protons flow from the intermembrane space into the matrix.In what direction do protons flow during chemiosmosis in chloroplasts?

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

Question 9

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 10

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 11

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

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

Question 12

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 of the following relationships would you expect to find when the cell is examined in the light?

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

Question 13

Which of the following reactions produces the oxygen released by photosynthesis?

A)reduction of NADP⁺
B)splitting of water molecules
C)chemiosmosis
D)electron transfer in photosystem I.

Question 14

Chemiosmosis in chloroplasts involves which of the following processes?

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 from carbon dioxide

Question 15

Which of the following statements correctly describes a reaction 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 oxygen (O₂).

Question 16

What is the primary function of the pigment molecules in a light-harvesting complex?

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

Question 17

Imagine that a researcher has developed a way to isolate thylakoids from chloroplasts and to make the pH of the thylakoid space acidic.If these isolated thylakoids are transferred to a pH8 solution in the dark,what might the researcher expect to observe?

A)that the isolated thylakoids produce ATP
B)that the isolated thylakoids produce glucose
C)that the isolated thylakoids reduce NADP⁺ to NADPH
D)that the isolated thylakoids produce oxygen gas

Question 18

Which of the following statements correctly describes an activity directly associated with photosystem I?

A)It produces ATP by substrate-level phosphorylation.
B)It receives electrons from the electron transport chain associated with thylakoid membranes.
C)It produces O₂.
D)It extracts hydrogen electrons released by the splitting of water.

Question 19

Which of the following statements correctly summarizes a redox reaction that occurs in photosynthesis?

A)Glucose is oxidized to form CO_2.
B)CO₂ is oxidized to form glucose.
C)CO₂ is reduced to form glucose.
D)Water is reduced to form O_2.
E)O₂ is oxidized to form water.

Question 20

Some photosynthetic organisms contain chloroplasts that lack photosystem II,yet they are able to survive.Which of the following experimental approaches would be a reasonable way to detect the lack of photosystem II in these organisms?

A)Determine if they have thylakoid membranes in the chloroplasts.
B)Test whether they release O₂ in the light.
C)Test whether they fix CO₂ in the dark.
D)Test the action spectrum for photosynthesis.

Question 21

Photophosphorylation in photosynthesis is most similar to which of the following processes associated with cellular respiration?

A)substrate-level phosphorylation in glycolysis
B)pyruvate oxidation in the production of acetyl-CoA
C)oxidation of NADH in anerobic fermentation
D)oxidative phosphorylation in mitochondria

Question 22

In mitochondria,the electron transport chain pumps protons from the matrix into the intermembrane space.In what direction are protons pumped by the electron transport chain in chloroplasts?

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

Question 23

Carotenoids are found in several 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 absorb and dissipate excess light energy that might otherwise react with oxygen to form harmful oxidative molecules.
D)They absorb orange light,enhancing the efficiency of photosynthesis.

Question 24

Some photosynthetic bacteria (e.g. ,purple sulfur bacteria)have only photosystem I,whereas others (e.g. ,cyanobacteria)have both photosystem I and photosystem II.No photosynthetic bacteria have only photosystem II.Which of the following might be a possible explanation for this observation?

A)Both photosystems evolved together,and photosystem II was selected against in some species.
B)Photosynthesis with only photosystem I is more ancestral.
C)Photosystem I is more efficient at photosynthesis than both photosystems I and II together.
D)Linear electron flow is more primitive than cyclic flow of electrons.

Question 25

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

A)ATP
B)FAD
C)FADH₂
D)NADPH
E)CO₂

Question 26

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

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 27

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 28

P680⁺ is often considered 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 greater affinity for electrons than oxygen has.
E)It has a positive charge.

Question 29

In photosynthetic cells,which reactions is (are)responsible for the synthesis of ATP by chemiosmosis?

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

Question 30

Where are ATP synthase complexes located in a plant cell?

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

Question 31

What is the primary function of the Calvin cycle?

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

Question 32

Generation of proton gradients across membranes occurs during which of the following reactions?

A)photosynthesis only
B)cellular respiration only
C)both photosynthesis and cellular respiration
D)photosynthesis,cellular respiration,and alcohol fermentation in yeast

Question 33

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 34

Where are electron transport chains that are responsible for ATP production located in plant cells?

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

Question 35

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 36

Which of the following metabolic pathways produce(s)reduced soluble electron carriers?

A)only the light reactions of photosynthesis
B)only the Calvin cycle
C)only 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 37

Where is 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)inner membrane of mitochondria

Question 38

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

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

Question 39

If plants are grown in the light with CO₂ containing a radioactive isotope of 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)mitochondria.

Question 40

How would you predict that doubling the atmospheric CO₂ concentration would affect C₃ plants?

A)They will experience increased rates of photosynthesis and growth.
B)They will experience increased rates of photorespiration and decreased growth rates.
C)They will experience decreased rates of photosynthesis and growth.
D)They will experience increased rates of photosynthesis,increased water loss through stomata,and decreased growth rates.

Question 41

When plants produce excess carbohydrates,the extra sugar is generally stored in which of the following forms?

A)glyceraldehyde 3-phosphate (G3P)
B)glucose
C)cellulose
D)starch

Question 42

The enzyme rubisco plays a critical role in carbon fixation in which of the following types of plants?

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 43

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 44

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 45

In most plants the carbohydrates produced by photosynthesis are transported out of the leaves to the rest of the plant as which of the following molecules?

A)glyceraldehyde 3-phosphate (G3P)
B)glucose
C)sucrose
D)starch

Question 46

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.

Question 47

A spaceship designed to support human life for a multiyear voyage to the outer planets of the solar system will include plants to provide oxygen and consume carbon dioxide.Because the spaceship will have limited exposure to the sun for extensive periods,an artificial light source will be needed to support photosynthesis.What wavelengths of light should be used to maximize plant growth with a minimum expenditure of energy?

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

Question 48

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 bacteria would congregate toward the two ends of the algal filament.
E)The number of bacteria would decrease due to a lack of oxygen.

Question 49

Which of the following statements is an accurate comparison of C₃ and C₄ plants

A)C₄ plants can continue to fix CO₂ even at relatively low CO₂ concentrations and high oxygen concentrations,whereas C₃ plants cannot.
B)C₄ plants have higher rates of photorespiration than C₃ plants.
C)C₄ plants fix carbon during the day,whereas C₃ plants fix carbon at night.
D)C₄ plants grow better in cool,moist climates,whereas C₃ plants grow better in hot,arid climates.

Question 50

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 51

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 52

Figure 8.2
Use Figure 8.2 and the compounds labeled A,B,C,D,and E to answer the following question.Which molecule in the Calvin cycle also serves as the substrate for the first step in the energy payoff phase of glycolysis?

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

Question 53

Why does photorespiration decrease the efficiency of photosynthesis?

A)It increases the amount of carbon dioxide consumed.
B)It reduces the amount of water consumed.
C)It reduces the amount of sugar produced.
D)It produces excess NADPH but less ATP.
E)It inhibits electron transfers from photosystem II.

Question 54

Cellular respiration in plant cell mitochondria consumes approximately what proportion of the organic molecules produced by photosynthesis?

A)5%
B)25%
C)50%
D)80%

Question 55

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 56

Photorespiration occurs when rubisco combines RuBP with which of the following molecules?

A)CO₂
B)O₂
C)glyceraldehyde 3-phosphate
D)H₂O

Question 57

An early step in the process of carbon fixation combines three molecules of CO₂ with three molecules of RuBP to produce three 6-carbon molecules,which are immediately converted to six 3-carbon molecules.These six molecules are phosphorylated and reduced to produce glyceraldehyde 3-phosphate (G3P).What additional events occur to complete the Calvin cycle?

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

Question 58

Which of the following metabolic processes consume(s)CO₂?

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 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 found that the largest groups were found in the areas illuminated by the red and blue light.This experiment helped to determine the relationship between which of the following parameters?

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 60

The NADPH required for the Calvin cycle is produced by which of the following metabolic reactions?

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

Question 61

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 62

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 63

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 64

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 65

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

Question 66

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 67

A gardener is concerned that her greenhouse is getting too hot from too much light.She plans to shade her plants with colored translucent plastic filters that allow only a narrow part of the visible light spectrum to pass through.To reduce the overall light energy but still maximize plant growth,she should use a filter that allows the passage of which of the following colors of light?

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

Question 68

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.