Deck 10: Photosynthesis

Question 1

Use the following figure to answer the question.

Halobacterium has a photosynthetic membrane that appears purple. Its photosynthetic action spectrum is the inverse of the action spectrum for green plants (see figure). 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) violet and blue
C) green and yellow
D) blue and red

Answer 1

C

Question 2

Why are the reaction centers of photosystems composed of several structurally different pigments?

A) Excited electrons must pass through several pigments before they can be transferred to electron acceptors of the electron transport chain.
B) This arrangement enables the plant to absorb light energy of a variety of wavelengths.
C) This arrangement enables the plant to absorb more photons from light energy, all of which are at the same wavelength.
D) This arrangement enables the reaction center to excite electrons to a higher energy level.

Answer 2

B

Question 3

In which of the following organisms did the process of photosynthesis most likely originate?

A) in plants
B) in prokaryotes
C) in fungi
D) three separate times during evolution

Answer 3

B

Question 4

Which of the following events accompanies absorption of energy by chlorophyll molecules of the reaction-center complex?

A) ATP is synthesized from the energy absorbed.
B) An electron is excited.
C) NADP⁺ is reduced to NADPH.
D) A molecule of water is split.

Question 5

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. Which of the following statements describes a relationship that Engelmann's experiment helped to determine?

A) the relationship between wavelength of light and the rate of aerobic respiration
B) the relationship between wavelength of light and the amount of heat released
C) the relationship between wavelength of light and the rate of photosynthesis
D) the relationship between carbon dioxide concentration and the rate of photosynthesis

Question 6

Use the following figure to answer the question.

What wavelength of light in the figure is most effective in driving photosynthesis?

A) 420 nm
B) 575 nm
C) 625 nm
D) 730 nm

Question 7

Which molecule is the final electron acceptor for electrons from photosystem I?

A) oxygen
B) chlorophyll in photosystem II
C) carbon dioxide
D) NADP⁺

Question 8

Under what conditions do photosynthesis and cellular respiration occur in plants?

A) Photosynthesis and cellular respiration occur only in the light.
B) Photosynthesis occurs only in the light, and cellular respiration occurs only in the dark.
C) Photosynthesis occurs only in the light, and cellular respiration occurs in both the dark and the light.
D) Photosynthesis and cellular respiration occur in both the dark and the light.

Question 9

Paper chromatography is a technique used to separate molecules based upon their size and solubility in a particular solvent. If pigments from a particular species of plant are extracted and subjected to paper chromatography, which of the following results is most likely?

A) Paper chromatography would produce a single band of pigment that is characteristic of that particular plant.
B) Paper chromatography would separate the pigments into two bands that appear green.
C) Paper chromatography would separate the pigments into several bands that appear green or yellow/orange.
D) Paper chromatography would separate the pigments into two bands, one that appears blue and one that appears red.

Question 10

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. Since the spaceship will be too far from the sun for photosynthesis, an artificial light source will be needed. Suppose a plant has a unique photosynthetic pigment and the leaves of this plant appear to be reddish yellow. What wavelengths of visible light are absorbed by this pigment?

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

Question 11

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

A) They split water and release oxygen from the reaction-center chlorophyll.
B) They absorb and transfer light energy to the reaction-center chlorophyll.
C) They synthesize ATP from ADP and ᵢ.
D) They transfer electrons to NADP⁺.

Question 12

What happens to the free energy released as electrons are passed from photosystem II to photosystem I through a series of electron carriers?

A) It excites electrons of the reaction center in photosystem I.
B) It is used to establish and maintain a proton gradient.
C) It is used to synthesize ATP through substrate-level phosphorylation.
D) It is used to phosphorylate NAD⁺ to NADPH.

Question 13

Use the following figure to answer the question.

If photosynthesizing green algae are provided with CO₂ containing heavy oxygen (¹⁸O), which of the following molecules produced by the algae (refer to the accompanying figure) will fail to contain ¹⁸O in later biochemical analyses?

A) glyceraldehyde 3-phosphate (G3P)
B) 3-phosphoglycerate
C) ribulose bisphosphate (RuBP)
D) ADP

Question 14

The oxygen released by photosynthesis is produced by which of the following processes?

A) splitting water molecules
B) chemiosmosis
C) the electron transfer system of photosystem I
D) the electron transfer system of photosystem II

Question 15

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

Question 16

Which of the following statements correctly describes a distinction between autotrophs and heterotrophs?

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

Question 17

Use the following figure to answer the question.

The figure 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) Oxygen given off during photosynthesis interferes with the absorption of light.
C) Other pigments absorb light in addition to chlorophyll a.
D) Aerobic bacteria take up oxygen, which changes the measurement of the rate of photosynthesis.

Question 18

In autotrophic bacteria, where is chlorophyll located?

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

Question 19

In autumn, chlorophyll is degraded in the leaves of deciduous trees. Why do the leaves change color to shades of yellow, orange, or red?

A) Sugars from sap fill the leaves prior to winter.
B) Degraded chlorophyll changes into many other colors.
C) In the absence of photosynthesis, the leaves produce energy exclusively by aerobic cellular respiration.
D) Other pigments such as carotenoids are still present in the leaves.

Question 20

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. Since 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) UV light

Question 21

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

A) Cellular respiration runs the biochemical pathways of photosynthesis in reverse.
B) Photosynthesis stores energy in complex organic molecules; cellular respiration releases energy from complex organic molecules.
C) Photosynthesis occurs only in plants; cellular respiration occurs only in animals.
D) Photosynthesis is catabolic; cellular respiration is anabolic.

Question 22

Which of the following events are associated with chemiosmosis in chloroplasts?

A) The pH of the stroma increases and ATP is synthesized.
B) The pH of the thylakoid space increases and ATP is synthesized.
C) The pH of the cytoplasm outside the chloroplast decreases and ATP is synthesized.
D) The pH of the stroma decreases and ATP is hydrolyzed.

Question 23

What are the products of cyclic electron flow during the light reactions of photosynthesis?

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

Question 24

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) orange
D) Any color will work equally well.

Question 25

Carbon dioxide is split to form oxygen gas and carbon compounds in which of the following metabolic pathways?

A) only photosynthesis
B) only respiration
C) photosynthesis and respiration
D) neither photosynthesis nor respiration

Question 26

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

A) matrix to the stroma
B) stroma to the thylakoid space
C) thylakoid space to the matrix
D) thylakoid space to the stroma

Question 27

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

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

Question 28

Which of the following processes would be most directly affected if a thylakoid membrane is punctured so that the interior of the thylakoid is no longer separated from the stroma?

A) splitting of water
B) flow of electrons from photosystem II to photosystem I
C) synthesis of ATP
D) reduction of NADP⁺

Question 29

Where are ATP synthase complexes located in plant cells?

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

Question 30

Which of the following processes 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

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 of photosynthesis.
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.

Question 32

Which of the following processes is directly associated with photosystem I?

A) receiving electrons from the thylakoid membrane electron transport chain
B) generation of molecular oxygen
C) extraction of hydrogen electrons from the splitting of water
D) passing electrons to NADP⁺

Question 33

What are the products of linear electron flow during the light reactions of photosynthesis?

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

Question 34

The mechanism of photophosphorylation is most similar to which of the following processes?

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

Question 35

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.

Question 36

In a plant, which of the following reactions produce molecular oxygen (O₂)?

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

Question 37

What is the relationship between the 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.

Question 38

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

A) Determine whether they have thylakoid membranes.
B) Determine whether they consume CO₂ in the dark.
C) Determine whether they produce O₂ in the light.
D) Determine the action spectrum for photosynthesis in these organisms.

Question 39

A flask containing photosynthetic green algae and a control flask containing water with no algae are both placed under a bank of lights that is 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. The dissolved oxygen in the flask with algae will ________.

A) always be higher
B) always be lower
C) be higher in the light, but the same in the dark
D) be higher in the light, but lower in the dark

Question 40

In photosynthetic cells, synthesis of ATP by chemiosmosis occurs during ________.

A) photosynthesis only
B) respiration only
C) photosynthesis and respiration
D) photosynthesis, respiration, and fermentation

Question 41

Why might the alternative pathways of photosynthesis using C₄ or CAM systems be described as metabolic compromises?

A) Both pathways increase the rate of photosynthesis but also increase the rate of water loss.
B) The CAM pathway allows more CO₂ into the plant but also increases the rate of water loss.
C) The C₄ pathway decreases water loss but also increases the rate of photorespiration.
D) Both pathways minimize photorespiration but also expend more ATP during carbon fixation.

Question 42

Where in a plant cell does the Calvin cycle take place?

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

Question 43

What would be a likely consequence of a mutation in plants that results in a photorespiration deficiency?

A) Photosynthetic efficiency would be reduced at low light intensities.
B) Cells would carry on the Calvin cycle at a much slower rate.
C) There would be more cellular damage from harmful products of the light reactions of photosynthesis.
D) Less oxygen would be produced by photosynthesis.

Question 44

Compared to C₃ plants, C₄ plants ________.

A) can continue to fix CO₂ even at lower CO₂ concentrations and higher oxygen concentrations
B) have higher rates of photorespiration
C) do not use rubisco for carbon fixation
D) make a four-carbon compound, oxaloacetate, which is then delivered to the citric acid cycle in mitochondria

Question 45

The reducing power for Calvin cycle reactions is provided by which of the following molecules?

A) ATP
B) NADH
C) NADP⁺
D) NADPH

Question 46

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.

Question 47

In the initial step in carbon fixation, a molecule of CO₂ is attached to RuBP to produce a six-carbon molecule, which is immediately split to produce two molecules of 3-phosphoglycerate. After phosphorylation and reduction produces glyceraldehyde 3-phosphate (G3P), what more needs to occur to complete the Calvin cycle?

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

Question 48

Use the following figure to answer the question.

Referring to the accompanying figure, where would elevated concentrations of oxygen inhibit carbon fixation reactions?

A) cell I only
B) cell II only
C) neither cell I nor cell II
D) both cell I and cell II

Question 49

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) ATP and NADPH

Question 50

Which of the following processes occurs during the Calvin cycle?

A) reduction of NADPH
B) release of oxygen
C) regeneration of the CO₂ acceptor
D) production of ATP

Question 51

Use the following figure to answer the question.

Which of the following statements is true concerning the accompanying figure?

A) It represents a C₄ photosynthetic system.
B) It represents an adaptation that maximizes photorespiration.
C) It represents a C₃ photosynthetic system.
D) It represents a CAM photosynthetic system.

Question 52

Which of the following statements summarizes the metabolic results of photorespiration?

A) It produces ATP and consumes oxygen and carbon dioxide.
B) It produces carbon dioxide and consumes ATP and oxygen.
C) It produces oxygen and consumes ATP and carbon dioxide.
D) It produces oxygen and ATP and consumes carbon dioxide.

Question 53

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) NADP → Helectron transport chain → O₂

Question 54

Students conducted an experiment to determine the effect of light intensity on the rate of photosynthesis. They punched 40 leaf disks from spinach leaves and used a syringe partially filled with water to pull the gases from the leaf disks so that all leaf disks sunk to the bottom of the syringe. Ten leaf disks from the syringe were placed in each of four cups and covered with 50 ml of the solutions as indicated below. All leaf disks were resting on the bottom of the cups when the experiment began. The volume of liquid in each cup and the temperature of the solutions were held constant. All cups were placed 0.5 meters from the designated light source. A large beaker of water was placed between the light and the cups to act as a heat sink to prevent a change in temperature. At the end of 10 minutes, the number of disks floating in each cup was recorded.

Use your knowledge of the mechanism of photosynthesis and the data presented in the chart to determine which of the statements is a correct explanation for the students' data.

A) Cup 1 had a low rate of photosynthesis because 0.5 grams of baking soda did not provide a sufficient amount of CO₂.
B) Cup 2 had the highest rate of photosynthesis because it had the highest ratio of disks floating to wattage of light.
C) Cup 3 had the same rate of photosynthesis as Cup 1 because they had the same ratio of disks floating to wattage of light.
D) Cup 4 had the lowest rate of photosynthesis because it had the least CO₂.

Question 55

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) NADPH → electron transport chain → O₂

Question 56

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?

A) The CO₂ acceptor concentration would decrease when either the CO₂ or light are cut off.
B) The CO₂ acceptor concentration would increase when either the CO₂ or light are cut off.
C) The CO₂ acceptor concentration would decrease when the CO₂ is cut off, but increase when the light is cut off.
D) The CO₂ acceptor concentration would increase when the CO₂ is cut off, but decrease when the light is cut off.

Question 57

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 conserve water more efficiently.
D) They exclude oxygen from their tissues.

Question 58

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

A) All plants would have faster growth rates.
B) C₃ plants would have faster growth rates; C₄ plants would be minimally affected.
C) C₄ plants would have faster growth rates; C₃ plants would be minimally affected.
D) C₃ plants would have faster growth rates; C₄ plants would have slower growth rates.

Question 59

CAM plants keep stomata closed in the 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 photosystem I and photosystem II at night

Question 60

Use the following figure to answer the question.

Refer to the accompanying figure and the molecules labeled A, B, C, D, and E. 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

Question 61

How is photosynthesis similar in C₄ plants and CAM plants?

A) In both cases, only photosystem I is 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 62

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) transfer of energy from pigment molecule to pigment molecule
D) ATP synthesis

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

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