Campbell Chapter 10: Mastering Biology Questions – Flashcards
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Which of these equations best summarizes photosynthesis?
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6 CO2 + 6 H2O > C6H12O6 + 6 O2
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Where does the Calvin cycle occur?
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Stroma
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The light reactions of photosynthesis use _____ and produce _____.
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water ... NADPH
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The light reactions of photosynthesis use _____ and produce _____.
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water ... NADPH
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The photosynthetic membranes are found in the _____ in plant cells.
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chloroplasts
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Which term describes ATP production resulting from the capture of light energy by chlorophyll?
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Photophosphorylation
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True or false? The chemiosmotic hypothesis states that the synthesis of ATP generates a proton gradient that leads to electron flow through an electron transport chain.
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False
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According to the chemiosmotic hypothesis, what provides the energy that directly drives ATP synthesis?
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Proton gradient
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Which of the following particles can pass through the ATP synthase channel?
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Protons
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True or false? The region of ATP synthase that catalyzes the production of ATP from ADP and inorganic phosphate spans the chloroplast membrane.
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False
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Chloroplast membrane vesicles are equilibrated in a simple solution of pH 5? . The solution is then adjusted to pH 8? . Which of the following conclusions can be drawn from these experimental conditions?
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ATP will not be produced because there is no ADP and inorganic phosphate in the solution.
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_____ has a longer wavelength than _____.
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Red ... green
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Which of the following is a product of the light reactions of photosynthesis?
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oxygen, ATP, and NADPH
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Photosynthesis is a redox reaction. This means that H2O is _____ during the light reactions and CO2 is _____ during the Calvin cycle.
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oxidized...reduced
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In the electromagnetic spectrum, the type of radiation that we call visible light occurs between _____.
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ultraviolet radiation and infrared radiation
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Approximately what wavelength of light is best absorbed by chlorophyll a, the pigment that participates directly in the light reactions?
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435 nm
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Which wavelength of light is best absorbed by chlorophyll b?
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455 nm
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You obtain the pigments called carotenoids in your diet when you eat carrots. Why do carotenoids appear yellow and orange?
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They absorb blue/green light and reflect yellow and red wavelengths of light.
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Can you tell from these absorption spectra whether red light is effective in driving photosynthesis?
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One cannot tell from this graph, but because chlorophyll a does absorb red light, we can predict that it would be effective in driving photosynthesis.
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If only chlorophyll a were involved in the light reactions, would blue light (wavelength about 490 nm) be effective in driving photosynthesis?
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The graph indicates that chlorophyll a absorbs very little blue light, so we can predict that blue light would not be effective.
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An action spectrum plots the rate of photosynthesis at various wavelengths of visible light, and it shows that blue light with a wavelength of about 490 nm is effective in driving photosynthesis. Based on this information and the absorption spectra shown at left, what role may chlorophyll b and carotenoids play in photosynthesis?
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These pigments are able to absorb more wavelengths of light (and thus more energy) than chlorophyll a alone can absorb. As part of light-harvesting complexes in photosystems, they broaden the range of light that can be used in the light reactions.
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The overall function of the Calvin cycle is _____.
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making sugar
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Carbon fixation involves the addition of carbon dioxide to _____.
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RuBP
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After 3-PGA is phosphorylated, it is reduced by _____.
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NADPH
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How many carbon dioxide molecules must be added to RuBP to make a single molecule of glucose?
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6
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In the Calvin cycle, how many ATP molecules are required to regenerate RuBP from five G3P molecules?
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3
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Which process produces oxygen?
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Photosynthesis
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Which set of reactions uses H2O and produces O2?
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The light-dependent reactions
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What is the importance of the light-independent reactions in terms of carbon flow in the biosphere?
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The light-independent reactions turn CO2, a gas, into usable carbon in the form of sugars.
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True or false? The light-dependent reactions of photosynthesis use water and produce oxygen.
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True
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Which of the following molecules is the primary product of photosystem I?
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NADPH
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What is the biological significance of the light-independent reactions of photosynthesis?
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They convert carbon dioxide to sugar.
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Which of the following statements best describes the relationship between the light-dependent and light-independent reactions of photosynthesis?
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The light-dependent reactions produce ATP and NADPH, which are then used by the light-independent reactions.
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Which of the following reactions ensures that the Calvin cycle can make a continuous supply of glucose?
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Regneration of RuBP
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Which of the following products of the light reactions of photosynthesis is consumed during the Calvin cycle?
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NADPH
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C4 plants occur more commonly in desert conditions because _____.
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they can fix carbon at the lower CO2 concentrations that develop when the stomata are closed
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In C3 plants the conservation of water promotes _____.
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photorespiration
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In C4 and CAM plants carbon dioxide is fixed in the _____ of mesophyll cells.
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cytoplasm
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C4 plants differ from C3 and CAM plants in that C4 plants _____.
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transfer fixed carbon dioxide to cells in which the Calvin cycle occurs
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Plants are photoautotrophs. What does this mean?
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They use light energy to drive the synthesis of organic molecules from inorganic materials.
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Which of the following does not occur during the Calvin cycle?
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release of oxygen
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Which process is most directly driven by light energy?
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removal of electrons from chlorophyll molecules
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The ultimate source of energy to support most life on Earth is _____.
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sunlight
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The light reactions of photosynthesis supply the Calvin cycle with
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ATP and NADPH.
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Which of the following statements is a correct distinction between autotrophs and heterotrophs?
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Autotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and other nutrients that are inorganic.
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In any ecosystem, terrestrial or aquatic, what group(s) is (are) always necessary?
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autotrophs
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When oxygen is released as a result of photosynthesis, it is a direct by-product of
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splitting water molecules.
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Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?
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ATP and NADPH
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Where does the Calvin cycle take place?
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stroma of the chloroplast
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The splitting of carbon dioxide to form oxygen gas and carbon compounds occurs during
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neither photosynthesis nor respiration
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Which statement describes the functioning of photosystem II?
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The electron vacancies in P680+ are filled by electrons derived from water.
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In mitochondria, chemiosmosis translocates protons from the matrix into the intermembrane space, whereas in chloroplasts, chemiosmosis translocates protons from
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the stroma to the thylakoid space.
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Generation of proton gradients across membranes occurs during
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both photosynthesis and respiration.
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Photorespiration occurs when rubisco reacts RuBP with
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O2.
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Compared to C3 plants, C4 plants
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can continue to fix CO2 even at relatively low CO2 concentrations and high oxygen concentrations.
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CAM plants keep stomata closed in daytime, thus reducing loss of water. They can do this because they
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fix CO2 into organic acids during the night.
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CAM plants keep stomata closed in daytime, thus reducing loss of water. They can do this because they
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fix CO2 into organic acids during the night.
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CAM plants keep stomata closed in daytime, thus reducing loss of water. They can do this because they
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fix CO2 into organic acids during the night.
