Photosynthesis Quiz

Photosynthesis

• Definition: Photosynthesis is a process used by plants and other organisms to convert light energy, typically from the sun, into chemical energy stored in carbohydrates.
• Carbon Fixation: The conversion of gaseous carbon dioxide into solid carbon during photosynthesis, occurring in the light-independent reactions (Calvin cycle).
• Equation: CO₂ + H₂O + photons → C₆H₁₂O₆ + O₂
• Light-Dependent Reactions:
  • Occur in the thylakoid membrane of chloroplasts.
  • Require light energy.
  • The ultimate source of energy for all life comes from light energy from the sun.
  • Require water (H₂O).
  • Water is broken apart by photosystem II, providing electrons for the reaction to occur.
  • Produce oxygen (O₂) as a waste product of breaking apart H₂O.
  • Function: Produce ATP and NADPH for the light-independent reactions (Calvin cycle).
  • Involve active and passive transport.
• Light-Independent Reactions (Calvin Cycle):
  • Occur in the chloroplast stroma.
  • Require ATP and NADPH produced in the light-dependent reaction.
  • Require carbon dioxide (CO₂) from the atmosphere.
  • Function: Ultimately produces glucose (C₆H₁₂O₆).
  • Carbon fixation occurs during this stage.

Chloroplast Structure

• Chloroplast: A double-membrane organelle involved in photosynthesis.
• Thylakoid: Membrane-bound compartments within the chloroplast, site of light-dependent reactions. The thylakoid membrane is where light-dependent reactions occur.
• Stroma: Fluid-filled space surrounding the thylakoids, where the light-independent reactions (Calvin cycle) occur.

Photosynthesis vs. Cellular Respiration

• Reactants/Products: The reactants of cellular respiration are the products of photosynthesis and vice-versa.
• Energy Conversion: Photosynthesis converts light energy to chemical energy; cellular respiration converts one type of chemical energy into another type of chemical energy.
• Process Type: Cellular respiration is catabolic (breaks down larger molecules, like glucose), while photosynthesis is anabolic (builds larger molecules, like glucose).
• Catabolism/Anabolism Example: Cellular respiration breaks down a larger molecule (C₆H₁₂O₆) into smaller molecules (CO₂). Photosynthesis makes larger molecules (C₆H₁₂O₆) from smaller molecules (CO₂). Example: Photosynthesis is anabolic; Cellular Respiration is catabolic.

Definitions

• Heterotroph: "Other-feeders," organisms that obtain organic compounds from other organisms (consumers). Dependent on photoautotrophs directly or indirectly.
• Autotroph: "Self-feeders," organisms that produce their own organic compounds (producers). The ultimate source of all organic compounds for non-autotrophic organisms.
• Chlorophyll: A pigment in chloroplasts absorbing light energy. Found in photosystems.
• Photon: A packet of light energy.
• Pigment: A substance absorbing visible light; its electrons elevate to a high energy state when visible light is absorbed.
• Photophosphorylation: ADP's phosphorylation in photosynthesis to create ATP, using light energy to attach the phosphate group.
• Thylakoid: Membrane bound compartments inside chloroplasts.

Cell Cycle and Reproduction

• Cell Cycle Phases: G1, S, G2, M (mitosis) phases in the cell cycle.
• Mitosis Phases: Four phases characterizing mitosis and its outcome.
• Meiosis: Two stages (Meiosis I and Meiosis II) of meiosis.
• Cell Cycle Regulation: Checkpoints and proteins control the cell cycle.
• Cancer: Uncontrolled cell growth.
• Apoptosis: Programmed cell death.
• Cell Cycle Reproduction: Sexual and asexual reproduction occur within the cell cycle.

Test your knowledge on the process of photosynthesis! This quiz covers the definition, carbon fixation, light-dependent and light-independent reactions, and the overall equation of photosynthesis. Challenge yourself and see how well you understand this vital biological process.