Questions and Answers
In C3 plants the conservation of water promotes _____
photorespiration
In C4 and CAM plants carbon dioxide is fixed in the _____ of mesophyll cells.
cytoplasm
C4 plants differ from C3 and CAM plants in that C4 plants _____.
transfer fixed carbon dioxide to cells in which the Calvin cycle occurs
Which of these equations best summarizes photosynthesis?
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Where does the Calvin cycle occur?
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The light reactions of photosynthesis use _____ and produce _____.
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Plants are photoautotrophs. What does this mean?
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Under what conditions do photosynthesis and cellular respiration occur in most plants?
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_____ has a longer wavelength than _____.
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In the electromagnetic spectrum, the type of radiation that we call visible light occurs between _____.
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Which of the following is a product of the light reactions of photosynthesis?
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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?
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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?
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Carbon dioxide is split to form oxygen gas and carbon compounds in which of the following metabolic pathways?
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Which process produces oxygen?
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Which set of reactions uses H2O and produces O2?
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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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True or false? The light-dependent reactions of photosynthesis use water and produce oxygen.
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Which of the following molecules is the primary product of photosystem I?
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What is the biological significance of the light-independent reactions of photosynthesis?
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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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Which molecule is regenerated in the regeneration phase of the Calvin cycle? Without regeneration of this molecule, the Calvin cycle would stop.
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The overall function of the Calvin cycle is _____.
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Which of the following sequences correctly represents the flow of electrons during photosynthesis?
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CAM plants keep stomata closed in the daytime, thus reducing loss of water. They can do this because they _____.
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Why are C4 plants able to photosynthesize with no apparent photorespiration?
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In which of the following plants would Photosystem II be most efficient?
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Which of the following is the product of the electron transport system in Photosystem II?
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You apply this research to the world's number one food crop, rice. Which of the following are you looking for using mass spectrometry?
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Why are reactive oxygen species problematic in Photosystem II?
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If plants could be genetically altered to improve Photosystem II, which of the following would occur?
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Why are plants classified as producers?
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Study Notes
Photosynthesis Overview
- Photosynthesis Equation: 6 CO2 + 6 H2O → C6H12O6 + 6 O2 summarizes the overall process.
- Location of Calvin Cycle: Occurs in the stroma of chloroplasts.
- Role of Light Reactions: Use water to produce NADPH, oxygen, and ATP.
Plant Types and Photosynthesis
- C3 Plants: Face photorespiration due to water conservation limiting CO2 availability.
- C4 and CAM Plants: Fix carbon in the cytoplasm of mesophyll cells, allowing them to minimize photorespiration.
- C4 Plants: Transfer fixed CO2 to the cells where the Calvin cycle occurs separately.
Importance of Light Reactions
- Light Reactions Products: Generate NADPH, ATP, and oxygen as by-products.
- Role of NADPH: Supplies energy for sugar production during the Calvin cycle.
Light-independent Reactions
- Importance: Convert CO2 into usable sugars, crucial for carbon flow within the biosphere.
- RuBP Regeneration: Essential for the Calvin cycle to continue, enabling continued carbon fixation.
Electrical Flow in Photosynthesis
- Electron Flow Sequence: H2O → NADPH → Calvin cycle illustrates how electrons move through the process.
- Photosystem II: Produces oxygen by splitting water and generating reactive oxygen species, which can damage proteins.
Plant Adaptations
- CAM Plants: Adapted to close stomata during the day, fixing CO2 into organic acids at night to conserve water.
- C4 Plants and PEP Carboxylase: Efficient photosynthesis without photorespiration via unique CO2 fixation.
Experimental Applications
- Oxygen Production: Plants modified to improve Photosystem II could enhance oxygen release.
- Mass Spectrometry in Rice: Identifying modified amino acid residues for agricultural research.
General Photosynthesis Facts
- Photoautotroph Definition: Plants that use light energy to synthesize organic molecules from inorganic materials.
- Reactive Oxygen Species: By-products of photosynthesis that can cause damage yet are part of essential processes.
Plant Classification
- Producers: Plants fix inorganic carbon into organic molecules, fulfilling a critical role in ecosystems.
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Description
Explore the essential processes of photosynthesis, including the equations that define it and the roles of light and light-independent reactions. This quiz covers the distinctions between C3, C4, and CAM plants, highlighting how these variations adapt to their environments. Test your knowledge of the Calvin cycle and the importance of light reactions in energy production.
