Biology - Photosynthesis

• What is the focus of national plant biology unit three?

  Life on air
• What is the basic photosynthesis equation?

  Water + Carbon Dioxide + Light → Oxygen + Sugar
• What is the role of chlorophyll in photosynthesis?

  It absorbs light energy for the process
• What are the two stages of photosynthesis?

  Light reactions and carbon fixation
• What happens during the light reactions of photosynthesis?

  Light energy is converted into chemical energy
• What is produced when water is split during photosynthesis?

  Hydrogen and oxygen
• What is the process of splitting water in photosynthesis called?

  Photolysis
• What is the significance of oxygen produced in photosynthesis?

  It is a waste product released into the atmosphere
• What is carbon fixation in photosynthesis?

  A series of enzyme-controlled reactions using CO2
• What are the three uses of sugar produced in photosynthesis?

  Energy source, storage, building material
• How is sugar stored in plants?

  As starch
• What is cellulose used for in plants?

  To build cell walls
• What are limiting factors in photosynthesis?

  Conditions that slow down the rate of photosynthesis
• What are the three limiting factors of photosynthesis?

  Carbon dioxide concentration, light intensity, temperature
• Why is temperature a limiting factor in photosynthesis?

  It affects enzyme activity in reactions
• How does carbon dioxide concentration affect photosynthesis?

  Low concentration slows down the rate
• What happens to the rate of photosynthesis as light intensity increases?

  It increases until another factor limits it
• What occurs to enzymes at high temperatures during photosynthesis?

  They can denature and lose function
• What are the stages of photosynthesis and their functions?

  • Stage 1: Light Reactions
  • Light energy captured by chlorophyll
  • Converts to chemical energy (ATP)
  • Splits water into hydrogen and oxygen
  • Stage 2: Carbon Fixation
  • Uses hydrogen and ATP from stage 1
  • Combines with carbon dioxide to produce sugar
• What are the fates of sugar produced in photosynthesis?

  • Used immediately for energy (respiration)
  • Stored as starch
  • Used as building material (cellulose)
• What are the effects of limiting factors on photosynthesis?

  • Carbon dioxide concentration: Low levels slow down the rate
  • Light intensity: Increases rate until limited by another factor
  • Temperature: Affects enzyme activity; too high can denature enzymes