Deck 11: Photosynthetic Processes

Question 1

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

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

Answer 1

A

Question 2

Which of the following statements best describes the conditions under which the Calvin cycle and cellular respiration occur in plants?

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

Answer 2

D

Question 3

If various plant cell membranes are isolated and incubated with a proton gradient across the isolated membrane in the presence of ADP and i, which of the following samples are most likely to be able to synthesize ATP?

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

Answer 3

C

Question 4

Lab students placed ten spinach leaf disks in each of three test tubes containing a baking soda solution and a control tube without baking soda. The volume of liquid in each tube and the temperature of the solutions were held constant. All tubes were placed an equal distance from a light source as indicated in the accompanying table. After 10 minutes, the amount of oxygen present in each sample was measured.

Which tube is expected to contain the greatest quantity of oxygen?

A) Tube 1
B) Tube 2
C) Tube 3
D) Tube 4

Question 5

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

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

Question 6

A mutation that disrupts cyclic electron flow in the light reactions of photosynthesis will specifically reduce the production of which of the following molecules?

A) CO₂
B) ATP
C) NADPH
D) ADP and NADP+

Question 7

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 8

Which of the following statements best describes the relationship between autotrophs and heterotrophs?

A) Autotrophs produce their organic molecules from CO₂ and other inorganic molecules, whereas heterotrophs obtain their organic molecules from compounds produced by other organisms.
B) Heterotrophs produce their organic molecules from CO₂ and other inorganic molecules, whereas autotrophs obtain their organic molecules from compounds produced by other organisms.
C) Both autotrophs and heterotrophs produce some of their organic molecules from CO₂ and other inorganic molecules.
D) Heterotrophs are considered the producers of the biosphere, whereas autotrophs are consumers.

Question 9

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

A) Only heterotrophs perform cellular respiration.
B) Only heterotrophs have mitochondria.
C) Only autotrophs can produce organic molecules from CO₂ and other inorganic materials.
D) Only autotrophs require oxygen to produce organic molecules.

Question 10

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

A) land plants
B) prokaryotes
C) fungi
D) unicellular aquatic eukaryotes

Question 11

Which of the following observations would be the best indicator that an organism lacks photosystem II?

A) It produces glucose in the light and dark.
B) It does not produce CO₂ in the dark.
C) It does not produce O₂ in the light.
D) It produces CO₂ in the light.

Question 12

Lab students placed ten spinach leaf disks in each of three test tubes containing a baking soda solution and a control tube without baking soda. The volume of liquid in each tube and the temperature of the solutions were held constant. All tubes were placed an equal distance from the light source indicated in the accompanying table. After 10 minutes, the amount of oxygen present in each sample was measured.

Which tube is expected to produce the least amount of oxygen?

A) Tube 1
B) Tube 2
C) Tube 3
D) Tube 4

Question 13

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 14

In chloroplasts, the photosynthetic electron transport chain acidifies which of the following cellular compartments?

A) mitochondrial matrix
B) stroma
C) thylakoid space
D) cytosol

Question 15

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 cytosol outside the chloroplast decreases and ATP is synthesized.
D) The pH of the stroma decreases and ATP is hydrolyzed.

Question 16

ATP is synthesized in plant cells by chemiosmosis in which of the following processes?

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

Question 17

Which of the following statements best describes 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 18

Researchers discovered that carbon fixation in spinach leaves utilizes 45,000 molecules of ATP and 30,000 molecules of NADPH in an hour. The deficit in ATP required for carbon fixation is most directly made up for by which of the following processes?

A) substrate level phosphorylation
B) mitochondrial electron flow
C) cyclic electron flow
D) linear electron flow

Question 19

Carotenoids are often found in foods that are considered to have antioxidant properties in human nutrition. Which of the following statements best describes a related function they serve 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 20

P680+ is said to be the strongest biological oxidizing agent. The strong oxidizing potential of P680+ is essential for its function because it ________.

A) is the receptor for the most excited electron in either photosystem of photosynthesis
B) is the molecule that transfers electrons to plastoquinone (Pq) of the electron transfer system
C) transfers its electrons to reduce NADP+ to NADPH
D) obtains electrons from the oxygen atom in a water molecule

Question 21

Which of the following statements describes a primary benefit of having photosystem reaction centers 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.

Question 22

In autumn, chlorophyll is degraded in the leaves of deciduous trees. Which of the following statements best explains the change in color from green to shades of yellow, orange, or red?

A) Sugars from sap fill the leaves prior to winter.
B) Degraded chlorophyll appears yellow, orange, or red.
C) In the absence of photosynthesis, the leaves produce energy exclusively by aerobic cellular respiration.
D) Other pigments such as carotenoids remain in the leaves after the chlorophyll is degraded.

Question 23

When a filament of algae is illuminated with light that is passed through a prism, different segments of algae are exposed to different wavelengths of light. When aerobic bacteria are present, they congregate in highest concentrations in the areas illuminated by the red and blue light. Which of the following statements provides the best explanation for the bacteria congregation in these areas?

A) Red and blue light increase the temperature in these areas.
B) The highest concentrations of oxygen are available in these areas.
C) Bacteria are attracted to red and blue light.
D) Bacteria congregate in areas with relatively low rates of photosynthesis.

Question 24

Which of the following describes 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 25

Paper chromatography is a technique used to separate molecules based upon their polarity. If pigments from oak leaves are extracted and subjected to paper chromatography, which of the following statements best describes the pigment bands that would be observed?

A) a single green band
B) two green bands
C) several bands that appear green, yellow, or orange
D) one red band and one blue band

Question 26

Which of the following events is most immediately associated with the 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 27

A flask containing photosynthetic green algae and a control flask containing only water are exposed to a cycle of 12 hours of light and 12 hours of darkness. Which of the following statements best describes how the relative dissolved oxygen concentration in the flask with algae will compare to the control flask?

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

Question 28

Which of the following processes is driven by the free energy released as electrons move through photosystem II and I in the thylakoid membranes?

A) excitement of electrons in the reaction center of photosystem I
B) establishment of a proton gradient
C) synthesis of ATP through substrate-level phosphorylation
D) phosphorylation of NAD+ to NADPH

Question 29

When a filament of algae is illuminated with light that is passed through a prism, different segments of algae are exposed to different wavelengths of light. When aerobic bacteria are present, they congregate in highest concentrations in the areas illuminated by the red and blue light. These data suggest a relationship between which of the following variables?

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

Question 30

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 31

A plant with unique photosynthetic pigments has leaves that appear reddish yellow. Which of the following wavelengths of visible light are most effectively absorbed by this pigment?

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

Question 32

A greenhouse becomes excessively hot from too much sunlight. One solution is to shade the plants with colored translucent plastic sheets, the color of which allows passage of only that wavelength of light. Which of the following colors would reduce the overall light energy without reducing plant growth?

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

Question 33

In a plant, which of the following reactions produces 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 34

The accompanying figure shows the absorbance spectrum for a photosynthetic bacterium that appears purple. Which of the following wavelengths of light are maximally absorbed by this organism?

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

Question 35

The accompanying figure shows the absorption spectrum for chlorophyll a and the action spectrum for photosynthesis. Which of the following statements best explains the low rate of photosynthesis at 550 nm?

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 photosynthetic pigments absorb light in addition to chlorophyll a.
D) Chlorophyll a does not absorb 550 nm light well.

Question 36

On a spaceship designed to support 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 so far from the sun, an artificial light source will be needed to support photosynthesis. Which of the following wavelengths of light should be used to maximize plant growth?

A) a mixture of yellow and orange light
B) green light
C) a mixture of blue and red light
D) ultraviolet light

Question 37

Which of the following molecules is the final electron acceptor for electrons from photosystem I?

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

Question 38

Based on the accompanying figure, which of the following wavelengths of light is most effective in driving photosynthesis?

A) 440 nm
B) 575 nm
C) 660 nm
D) 720 nm

Question 39

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) oxidation of chlorophyll molecules

Question 40

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 41

Which of the following molecules best describes the primary form in which plants stockpile extra sugar produced by photosynthesis?

A) glucose
B) sucrose
C) cellulose
D) starch

Question 42

Which of the following processes occurs in the Calvin cycle?

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

Question 43

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) would be least likely to contain 18O in subsequent analyses?

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

Question 44

Which of the following statements best describes a characteristic of C4 plants?

A) They are able to fix CO₂ at lower CO₂ concentrations and higher oxygen concentrations than C3 plants.
B) They have higher rates of photorespiration than C3 plants.
C) They use rubisco for carbon fixation, whereas C3 plants do not.
D) They produce oxaloacetate, a four-carbon compound, which is then delivered to the citric acid cycle in mitochondria.

Question 45

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 46

Which of the following statements best explains the ability of CAM plants to synthesize sugars in the daytime while keeping their stomata closed to reduce water loss?

A) They fix CO₂ into organic acids during the night.
B) They fix CO₂ into sugars in the bundle-sheath cells.
C) They fix CO₂ into pyruvate in the mesophyll cells.
D) They use photosystem I and photosystem II at night.

Question 47

Which of the following molecules is the primary reducing agent in the Calvin cycle reactions?

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

Question 48

Most sugar is transported from the leaves to the rest of the plant in the form of which of the following molecules?

A) glucose
B) sucrose
C) G3P
D) starch

Question 49

A mutation that eliminates a plant's ability to perform photorespiration will most likely have which of the following effects on the plant?

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 50

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 51

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

A) ATP is produced, oxygen and carbon dioxide are consumed.
B) ATP is hydrolyzed, carbon dioxide is produced, and oxygen is consumed.
C) ATP is hydrolyzed, oxygen is produced, and carbon dioxide is consumed.
D) ATP and oxygen are produced and carbon dioxide is consumed.

Question 52

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

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

Question 53

Which of the following molecules will accumulate if light reactions occur normally, but the Calvin Cycle is inhibited?

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

Question 54

To identify the molecule that first reacts with CO₂ in the light-independent reactions of photosynthesis, Calvin and Benson manipulated the carbon-fixation cycle by either elminating CO₂ or light from cultures of photosynthetic algae. Which of the following statements best predicts the immediate effects of these manipulations on the concentration of the molecule that initially reacts with CO₂?

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

Question 55

Which of the following statements best explains why photosynthesis using C4 or CAM systems may be described as a metabolic compromise?

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 in the process of carbon fixation.

Question 56

In which cellular structure are the enzymes of the Calvin cycle localized?

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

Question 57

In which cell of the accompanying figure would elevated oxygen concentrations have the greatest inhibitory effect on 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 58

Which of the following statements best explains the ability of C4 plants to perform photosynthesis 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 59

Which of the following statements best describes 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 60

The light reactions supply the Calvin cycle with ________.

A) light energy
B) H₂O and ATP
C) CO₂ and NADPH
D) ATP and NADPH

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) reduction of NADP+ molecules
C) transfer of energy from pigment molecule to pigment molecule
D) ATP synthesis

Question 62

Which of the following occurs during the Calvin cycle?

A) carbon fixation
B) reduction of NADP+
C) release of oxygen
D) generation of CO₂

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.