Photosynthesis

• Photosynthesis


  A chemical reaction in which energy is transferred from the environment as light from the Sun to the leaves of a plant. This is an endothermic reaction.
• Photosynthetic reaction


  Carbon dioxide + water -> Glucose + Oxygen
• Limiting factors for photosynthesis

  • Temperature
  • Carbon dioxide concentration
  • Light intensity
  • Amount of chlorophyll
• As the distance of a light source from a plant increases

  The light intensity decreases
• Inverse square law


  Light intensity varies in inverse proportion to the square of the distance
• If you double the distance between a light source and a plant


  Light intensity falls by three-quarters
• Limiting factors often interact

  Any one may be limiting photosynthesis
• Interaction of limiting factors

  • Temperature limiting
  • Carbon dioxide and temperature limiting
  • Photosynthesis rate increases when both temperature and carbon dioxide are increased until another factor becomes limiting
• Commercial greenhouses control limiting factors to get the highest possible rates of photosynthesis so they can grow plants as quickly as possible or produce the highest yields, whilst still making a profit
• Uses of glucose produced in photosynthesis


  • Convert into insoluble starch for storage
  • For respiration to produce energy
  • Produce fat or oil (lipids) for storage
  • Produce cellulose to strengthen cell walls
  • Produce amino acids for protein synthesis