Chapter 10: Photosynthesis
39) 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.
D
4) In any ecosystem, terrestrial or aquatic, what group(s) is (are) always necessary? A) Autotrophs and heterotrophs. B) Producers and primary consumers. C) Photosynthesizers. D) Autotrophs. E) Green plants.
D
40) P680+ is said to be the strongest biological oxidizing agent. Why? 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.
D
45) 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.
D
2) 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, Pi, and NADP+. D) Electrons and H+. E) ATP and NADPH.
E
3) Photosynthesis is not responsible for: A) Oxygen in the atmosphere. B) The ozone layer. C) Most of the organic carbon on Earth's surface. D) Atmospheric CO2. E) Fossil fuels.
E
48) 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.
E
63) Which of the events listed below 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.
E
74) 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.
E
9) If photosynthesizing green algae are provided with CO2 synthesized with heavy oxygen (18O), later analysis will show that all but one of the following compounds produced by the algae contain the 18O label. That one is: A) 3-phosphoglycerate. B) Glyceraldehyde 3-phosphate (G3P). C) Glucose. D) Ribulose bisphosphate (RuBP). E) O2.
E
14) 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.
A
15) What wavelength of light in the figure is most effective in driving photosynthesis? A) 420 mm. B) 575 mm. C) 625 mm. D) 730 mm.
A
12) 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.
A
24) In autumn, the leaves of deciduous trees change colors. This is because chlorophyll is degraded and _____. A) Carotenoids and other pigments are still present in the leaves. B) The degraded chlorophyll changes into many other colors. C) Water supply to the leaves has been reduced. D) Sugars are sent to most of the cells of the leaves.
A
42) In plants, 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 is not part of photosynthesis.
A
57) 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.
A
60) 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.
A
66) 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
A
67) 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.
A
68) 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.
A
70) Reduction of NADP+ occurs during: A) Photosynthesis. B) Respiration. C) Both photosynthesis and respiration. D) Neither photosynthesis nor respiration. E) Photorespiration
A
75) 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 is not part of photosynthesis.
A
76) 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
A
79) 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.
A
8) Early investigators thought the oxygen produced by photosynthetic plants came from carbon dioxide. In fact, it comes from _____. A) Water. B) Glucose. C) Air. D) Electrons from NADPH
A
81) 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.
A
82) 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.
A
85) 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 out-competes rubisco for CO2. E) Use photosystem I and photosystem II at night.
A
91) Which of the following statements is true concerning the figure above? 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.
A
95) If the power fails and the lights go dark, what will happen to CO2 levels? A) CO2 will rise as a result of both animal and plant respiration. B) CO2 will rise as a result of animal respiration only. C) CO2 will remain balanced because plants will continue to fix CO2 in the dark. D) CO2 will fall because plants will increase CO2 fixation. E) CO2 will fall because plants will cease to respire in the dark.
A
37) 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; respiration releases energy from complex organic molecules. 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.
B
1) The process of photosynthesis probably originated _____. A) In plants. B) In prokaryotes. C) In fungi. D) Three separate times during evolution.
B
10) 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
B
19) 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.
B
20) 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) Blue, green, and red. 21) Halobacterium has
B
22) Why are there several structurally different pigments in the reaction centers of photosystems? 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) They enable the plant to absorb more photons from light energy, all of which are at the same wavelength. D) They enable the reaction center to excite electrons to a higher energy level.
B
23) If pigments from a particular species of plant are extracted and subjected to paper chromatography, which of the following is most likely? A) Paper chromatography for the plant would isolate a single band of pigment that is characteristic of that particular plant. B) Paper chromatography would separate the pigments from a particular plant into several bands. C) The isolated pigments would be some shade of green. D) Paper chromatography would isolate only the pigments that reflect green light.
B
29) In the thylakoid membranes, the pigment molecules in a light-harvesting complex _____. A) Split water and release oxygen from the reaction-center chlorophyll. B) Absorb and transfer light energy to the reaction-center chlorophyll. C) Synthesize ATP from ADP and Pi. D) Transfer electrons to ferredoxin and then NADPH.
B
30) 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.
B
31) 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.
B
41) 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.
B
43) The accumulation of free oxygen in Earth's atmosphere began with the origin of _____. A) Life and respiratory metabolism. B) Cyanobacteria using photosystem II. C) Chloroplasts in photosynthetic eukaryotic algae. D) Land plants.
B
44) In its mechanism, photophosphorylation is most similar to _____. A) Substrate-level phosphorylation in glycolysis. B) Oxidative phosphorylation in cellular respiration. C) The Calvin cycle. D) Reduction of NADP+.
B
46) 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 uses to reduce overall light energy but still maximize plant growth? A) Green. B) Blue. C) Orange. D) Any color will work equally well.
B
50) Refer to the figure above. 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
B
52) 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.
B
55) What would be the expected effect on plants if the atmospheric CO2 concentration was doubled? A) All plants would experience increased rates of photosynthesis. B) C3 plants would have faster growth; C4 plants would be minimally affected. C) C4 plants would have faster growth; C3 plants would be minimally affected. D) C3 plants would have faster growth; C4 plants would have slower growth.
B
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.
B
61) 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.
B
62) In the thylakoid membranes, what is the main role of the antenna pigment molecules? A) Split water and release oxygen to the reaction-center chlorophyll. B) Harvest photons and transfer light energy to the reaction-center chlorophyll. C) Synthesize ATP from ADP and Pi. D) Transfer electrons to ferredoxin and then NADPH. E) Concentrate photons within the stroma.
B
72) 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 lectron flow.
B
77) 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 is not part of photosynthesis.
B
80) 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 is not part of photosynthesis.
B
84) Photorespiration occurs when rubisco reacts RuBP with: A) CO2. B) O2. C) Glyceraldehyde 3-phosphate. D) 3-phosphoglycerate. E) NADPH.
B
86) Photorespiration lowers the efficiency of photosynthesis by: A) Carbon dioxide molecules. B) 3-phosphoglycerate molecules. C) ATP molecules. D) Ribulose bisphosphate molecules. E) RuBP carboxylase molecules.
B
88) If atmospheric CO2 concentrations increase twofold or more, how will plants be affected, disregarding any changes in climate? 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.
B
92) Referring to the above figure, oxygen would inhibit the CO2 fixation reactions in A) Cell I only. B) Cell II only. C) Neither cell I nor cell II. D) Both cell I and cell II. E) Cell I during the night and cell II during the day.
B
97) In mechanism, photophosphorylation is most similar to: A) Substrate-level phosphorylation in glycolysis. B) Oxidative phosphorylation in cellular respiration. Trial G r a m s o f soda (CO22 source) Wattage of light bulb Disks floating at 10 minutes 1 0.5 25 3 2 0.5 50 5 3 0.5 75 9 4 0 75 0 C) The Calvin cycle. D) Carbon fixation. E) Reduction of NADP+.
B
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. 16) 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.
B
11) Which of the following statements is a correct 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.
C
17) An outcome of Engelmann's experiment was to help determine the relationship between _____. A) Wavelengths of light and the rate of aerobic respiration B) Wavelengths of light and the amount of heat released C) Wavelengths of light and the rate of photosynthesis D) The concentration of carbon dioxide and the rate of photosynthesis
C
26) As electrons are passed through the system of electron carriers associated with photosystem II, they lose energy. What happens to this energy? A) It excites electrons of the reaction center of photosystem I. B) It is lost as heat. C) It is used to establish and maintain a proton gradient. D) It is used to phosphorylate NAD+ to NADPH, the molecule that accepts electrons from photosystem I.
C
27) The final electron acceptor associated with photosystem I is _____. A) Oxygen. B) Water. C) NADP. D) NADPH.
C
28) The electrons of photosystem II are excited and transferred to electron carriers. From which molecule or structure do the photosystem II replacement electrons come? A) The electron carrier, plastocyanin. B) Photosystem I. C) Water. D) Oxygen.
C
32) What are the products of linear electron flow? A) Heat and fluorescence. B) ATP and P700. C) ATP and NADPH. D) ADP and NADP+.
C
33) As a research scientist, you measure the amount of ATP and NADPH consumed by the Calvin cycle in 1 hour. You find that 30,000 molecules of ATP were consumed, but only 20,000 molecules of NADPH were consumed. Where did the extra ATP molecules come from? A) Photosystem II. B) Photosystem I. C) Cyclic electron flow. D) Linear electron flow.
C
36) 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.
C
38) 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
C
49) 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) Regeneration of ATP from ADP. C) Regeneration of RuBP. D) Regeneration of NADP+.
C
51) Refer to the figure above. 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 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.
C
53) 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.
C
58) 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, while C4 plants allow less CO2 into the plant.
C
59) If plant gene alterations cause plants to be deficient in photorespiration, what would most probably occur? 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 light-induced damage to the cells. D) Less oxygen would be produced.
C
6) In autotrophic bacteria, where are the enzymes located that can carry on carbon fixation (reduction of carbon dioxide to carbohydrate)? A) In chloroplast membranes. B) In chloroplast stroma. C) In the cytosol. D) In the nucleoid. E) In the infolded plasma membrane.
C
65) What are the products of linear photophosphorylation? A) Heat and fluorescence. B) ATP and P700. C) ATP and NADPH. D) ADP and NADP. E) P700 and P680.
C
69) 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) Photorespiration only.
C
7) Plants photosynthesize _____. A) Only in the light but respire only in the dark. B) Only in the dark but respire only in the light. C) Only in the light but respire in light and dark. D) And respire only in the light
C
71) Generation of proton gradients across membranes occurs during: A) Photosynthesis. B) Respiration. C) Both photosynthesis and respiration. D) Neither photosynthesis nor respiration. E) Photorespiration.
C
87) 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, while C4 plants allow less CO2 into the plant. E) C4 plants allow less water loss but CAM plants allow more water loss.
C
89) Plants photosynthesize only in the light. Plants respire: A) In the dark only. B) In the light only. C) Both in light and dark. D) Never-they get their ATP from photophosphorylation. E) Only when excessive light energy induces photorespiration.
C
90) 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 10.2 to help you in determining the correct answer. 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 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.
C
96) 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. E) In both cases, thylakoids are not involved in photosynthesis.
C
A spaceship is designed to support animal life for a multi-year voyage to the outer planets of the solar system.Plants will be grown to provide oxygen and to recycle carbon dioxide. 18) 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) Yellow light. E) UV light.
C
13) 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.
D
21) 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) Blue and red
D
25) What event accompanies energy absorption by chlorophyll (or other pigment molecules of the antenna complex)? A) ATP is synthesized from the energy absorbed. B) A carboxylation reaction of the Calvin cycle occurs. C) Electrons are stripped from NADPH. D) An electron is excited.
D
34) Assume a thylakoid is somehow punctured so that the interior of the thylakoid is no longer separated from the stroma. This damage will have the most direct effect on which of the following processes? A) The splitting of water. B) The absorption of light energy by chlorophyll. C) The flow of electrons from photosystem II to photosystem I. D) The synthesis of ATP. E) The reduction of NADP+.
D
35) 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.
D
47) 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. 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.
D
5) In autotrophic bacteria, where is chlorophyll located? A) In chloroplast membranes. B) In the ribosomes. C) In the nucleoid. D) In the infolded plasma membrane.
D
54) What compound provides the reducing power for Calvin cycle reactions? A) ATP. B) NADH. C) NADP+. D) NADPH.
D
64) 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.
D
73) 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).
D
78) In a plant leaf, the reactions that produce NADH 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 is not part of photosynthesis.
D
83) 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.
D
