Questions and Answers
What does it mean that plants are photoautotrophs?
They use light energy to drive the synthesis of organic molecules from inorganic materials.
Which of these phosphorylates ADP to make ATP?
_____ releases energy that is used to pump hydrogen ions from the stroma into the thylakoid compartment.
Photophosphorylation
_____ splits water into 1/2 O2, H+, and e-.
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Energized electrons from ____ enter an electron transport chain and are then used to reduce NADP+.
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Where can chlorophyll be found?
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Which of the following is a product of the light reactions of photosynthesis?
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What are the inputs of the Light Reaction?
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What are the outputs of the Light Reaction?
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What are the inputs of the Calvin Cycle?
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What is the output of the Calvin Cycle?
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In the light reactions, light energy is used to oxidize ______ to _______.
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The electrons derived from this oxidation reaction in the light reactions are used to reduce _________ to _________.
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The Calvin cycle oxidizes the light-reactions product ________ to ________.
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The electrons derived from this oxidation reaction in the Calvin cycle are used to reduce _________ to _________.
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What is the overall function of the Calvin cycle?
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What is the ultimate source of energy to support most life on Earth?
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Which products of the light reactions of photosynthesis are utilized in the Calvin cycle?
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Where does the Calvin cycle take place?
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What is the primary function of the Calvin cycle?
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Which equation 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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Which term describes ATP production resulting from the capture of light energy by chlorophyll?
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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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According to the chemiosmotic hypothesis, what provides the energy that directly drives ATP synthesis?
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Which particles can pass through the ATP synthase channel?
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The region of ATP synthase that catalyzes the production of ATP from ADP and inorganic phosphate spans the chloroplast membrane.
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What conclusion can be drawn when chloroplast membrane vesicles equilibrated in a simple solution of pH 5 is adjusted to pH 8?
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Which statement best describes the relationship between photosynthesis and respiration?
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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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The light-dependent reactions of photosynthesis use water and produce oxygen.
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Which molecule 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 statement best describes the relationship between the light-dependent and light-independent reactions of photosynthesis?
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Which reaction ensures that the Calvin cycle can make a continuous supply of glucose?
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When light strikes chlorophyll molecules, they lose electrons, which are ultimately replaced by _____.
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In the electromagnetic spectrum, the type of radiation that we call visible light occurs between _____ and _____.
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What is the final electron acceptor associated with photosystem I?
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Where are the photosynthetic membranes found in plant cells?
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Which product of the light reactions of photosynthesis is consumed during the Calvin cycle?
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Study Notes
Photosynthesis Overview
- Plants function as photoautotrophs, utilizing light energy to synthesize organic molecules from inorganic materials.
- Photosynthesis occurs in two main stages: light reactions and the Calvin cycle.
Light Reactions
- Light reactions occur in the thylakoid membranes, utilizing water and producing oxygen, NADPH, and ATP.
- Input components for light reactions include NADP+, water, ADP, and light.
- Key outcomes of light reactions are NADPH, O2, and ATP.
- Photophosphorylation refers to ATP production driven by light energy captured by chlorophyll.
- Electrons from water (H2O) are oxidized to produce oxygen (O2) and are then transferred to reduce NADP+ to NADPH.
Key Components
- Chlorophyll is located in the thylakoid membranes, capturing light energy.
- Energized electrons from chlorophyll enter the electron transport chain, powering the formation of NADPH.
Calvin Cycle
- The Calvin cycle takes place in the stroma of the chloroplast and synthesizes simple sugars from carbon dioxide.
- Inputs for the Calvin cycle are CO2, ATP, and NADPH, while outputs include ADP, G3P (a sugar), and NADP+.
- The cycle operates by using ATP and NADPH produced during the light reactions to convert CO2 into glucose.
Interconnections
- ATP and NADPH from light reactions are essential for driving the Calvin cycle.
- The synthesis of glucose during the Calvin cycle allows energy stored in complex organic molecules to be utilized by living organisms.
Photosynthesis Equations
- The overall equation summarizing photosynthesis is: 6 CO2 + 6 H2O → C6H12O6 + 6 O2.
Light-Dependent Reactions
- Light-dependent reactions involve the use of water and produce oxygen.
- These reactions lead to the generation of a proton gradient, crucial for ATP synthesis via ATP synthase.
Importance of Reactions
- The light-independent (Calvin cycle) reactions convert gaseous CO2 into usable sugars, playing a significant role in the carbon flow within the biosphere.
- Continuous regeneration of RuBP is essential to sustain the Calvin cycle and ensure a steady supply of glucose.
Spectral Regions
- Visible light is a narrow band of the electromagnetic spectrum located between ultraviolet and infrared radiation.
Electron Transport in Photosystems
- In photosystem I, the final electron acceptor is NADP+, which helps form NADPH for use in the Calvin cycle.
- Light energy causes chlorophyll to lose electrons, which are replenished by the splitting of water.
Membrane Structures
- Photosynthetic membranes, including thylakoid membranes within chloroplasts, are crucial for compartmentalizing reactions and facilitating photosynthesis.
Significance of Photosynthesis
- Photosynthesis ultimately supports life on Earth by converting sunlight into chemical energy stored in sugar, which is then accessible to various organisms.
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