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Light Reactions of Photosynthesis exam Flashcards

Light Reactions of Photosynthesis exam
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  • Thylakoids
    Green pancake-like structures in chloroplasts where light reactions occur.
  • What is the main purpose of the light reactions in photosynthesis?
    To produce ATP and NADPH while releasing oxygen as a byproduct.
  • Photosystem II
    The first photosystem in the light reactions that absorbs light and energizes electrons.
  • Where do the light reactions of photosynthesis take place?
    In the thylakoid membranes of chloroplasts.
  • Electron Transport Chain (ETC)
    A series of redox reactions that transfer electrons from photosystem II to photosystem I.
  • What is the role of water in the light reactions?
    Water is split to provide electrons and produce oxygen gas.
  • Chemiosmosis
    The process by which a hydrogen ion gradient is used to produce ATP.
  • What are the products of the light reactions?
    ATP, NADPH, and oxygen gas.
  • Photosystem I
    The second photosystem in the light reactions that re-energizes electrons.
  • What is NADP+?
    An electron carrier that is reduced to NADPH in the light reactions.
  • ATP Synthase
    An enzyme that uses the hydrogen ion gradient to produce ATP.
  • What is the final electron acceptor in the light reactions?
    NADP+, which is reduced to NADPH.
  • Photon
    A particle of light that provides energy for the light reactions.
  • What drives the synthesis of ATP in the light reactions?
    The hydrogen ion gradient created by the electron transport chain.
  • Oxygen Gas (O2)
    A byproduct of the light reactions produced from the splitting of water.
  • What is the role of photosystems in the light reactions?
    To absorb light and energize electrons.
  • NADPH
    An electron carrier that provides high-energy electrons for the Calvin cycle.
  • What happens to the electrons after they are energized in photosystem II?
    They travel through the electron transport chain to photosystem I.
  • Hydrogen Ion Gradient
    A concentration gradient of H+ ions that drives ATP synthesis.
  • What is the significance of the light reactions for the Calvin cycle?
    The ATP and NADPH produced in the light reactions fuel the Calvin cycle.
  • Stroma
    The fluid-filled space surrounding the thylakoids in chloroplasts.
  • What is the first step of the light reactions?
    Photosystem II absorbs photons and energizes electrons.
  • Reduction of NADP+
    The process of NADP+ gaining electrons to form NADPH.
  • What is the role of ATP in photosynthesis?
    To provide energy for the Calvin cycle.
  • Light Harvesting Complexes
    Structures in photosystems that contain pigments and proteins to absorb light.
  • What is the role of the electron transport chain in the light reactions?
    To transfer electrons and create a hydrogen ion gradient.
  • Calvin Cycle
    The second stage of photosynthesis that uses ATP and NADPH to synthesize glucose.
  • What happens to the oxygen produced in the light reactions?
    It can be used for cellular respiration or released into the atmosphere.
  • Photophosphorylation
    The process of generating ATP from ADP using the energy of sunlight.