Questions and Answers
What is the role of the carrier molecule NADP in photosynthesis?
NADP is an important molecule used in cellular respiration, converting into NADPH during glucose breakdown.
What is the role of chlorophyll molecules in photosynthesis?
Chlorophyll turns light into sugars which are used as fuel.
What are the main events of light-dependent reactions and where do they occur?
They involve light absorption, splitting of water, release of oxygen, and production of ATP and NADPH in thylakoids.
How is ATP produced as a result of light striking chlorophyll molecules during the light-dependent phase?
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What is non-cyclic photophosphorylation?
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Why is non-cyclic phosphorylation also known as non-cyclic photophosphorylation?
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How does cyclic photophosphorylation differ from non-cyclic photophosphorylation?
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What is the purpose of the cyclic pathway of electron flow in photosynthesis?
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How does the independence of Photosystem I provide a mechanism for the evolution of the photosynthetic pathway?
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Study Notes
NADP in Photosynthesis
- NADP functions as a carrier molecule in cellular respiration, converting to NADPH with the addition of hydrogen.
- NADPH plays a critical role in the energy-making process during photosynthesis.
Role of Chlorophyll
- Chlorophyll converts sunlight into chemical energy in the form of sugars for the plant's fuel.
Light Dependent Reactions
- Photosynthesis consists of light reactions and the Calvin Cycle, occurring in the chloroplasts.
- Light reactions take place in thylakoids, which contain chlorophyll.
- Steps of light reactions include:
- Light absorption causes water molecules to split, producing oxygen and H+ ions.
- Released O2 is exhaled; H+ combines with NADP+ to form NADPH.
- ATP is generated through photophosphorylation when ADP receives a phosphate.
- ATP and NADPH produced move on to power the Calvin Cycle.
ATP Production Mechanism
- Light hits chlorophyll, activating it and resulting in electron release.
- This activation initiates photolysis, splitting water into H+ and OH- ions.
- The end products include glucose, reduced NADP, water, oxygen, and ATP.
Non-Cyclic Photophosphorylation
- Non-cyclic photophosphorylation operates through two distinct photosystems (PS I and II) and the electron transport chain.
- Electrons flow in a one-way pattern from PS II to NADPH, resulting in the synthesis of both ATP and NADPH.
Characteristics of Non-Cyclic Pathway
- The process is termed non-cyclic because it does not follow a circular electron flow, moving solely from photosystem II to NADPH via photosystem I.
Cyclic vs. Non-Cyclic Photophosphorylation
- Cyclic photophosphorylation primarily supports ATP production for the Calvin Cycle and only utilizes Photosystem II's P680.
- Non-cyclic photophosphorylation encompasses both P680 (PS II) and P700 (PS I), generating both NADPH and ATP.
Purpose of Cyclic Electron Flow
- Cyclic electron flow allows electrons to cycle back to P700 in photosystem I, producing additional ATP without generating NADPH.
Independence of Photosystems
- The distinct requirements of photosystems (PS I needing electrons and PS II needing water) illustrate an evolutionary mechanism for photosynthetic pathways.
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Description
This quiz covers key concepts related to photosynthesis, focusing on the roles of molecules such as NADP and chlorophyll. Each flashcard provides definitions and explanations to enhance your understanding of this essential biological process.
