factors affecting photosynthesis

• Factors affecting photosynthesis


  • Light intensity
  • Temperature
  • Concentration of carbon dioxide in the air
  • Amount of chlorophyll in plants
• Chlorophyll


  Pigment within chloroplasts that absorbs the light energy needed for photosynthesis
• Plants have less chlorophyll


  They won't be able to carry out as much photosynthesis
• Factors that can reduce chlorophyll levels in plants include disease, environmental stress, and lack of nutrients like water
• Limiting factors for photosynthesis

  • Light
  • Carbon dioxide
  • Temperature
• Relationship between light intensity and rate of photosynthesis

  1. As light intensity increases, rate of photosynthesis increases

  2. Rate plateaus when something else becomes the limiting factor (e.g. carbon dioxide or temperature)
• Relationship between carbon dioxide concentration and rate of photosynthesis

  1. As carbon dioxide increases, rate of photosynthesis increases

  2. Rate plateaus when something else becomes the limiting factor
• Relationship between temperature and rate of photosynthesis

  1. As temperature increases, rate of photosynthesis increases

  2. Rate starts to drop as enzymes denature at higher temperatures (around 45°C)
• Information from this point onwards is higher tier GCSE biology
• Two experiments with different temperatures


  Comparison of the curves shows temperature was a limiting factor in the 15°C experiment
• Two experiments with different carbon dioxide concentrations

  Comparison of the curves shows carbon dioxide concentration was a limiting factor in the lower curve
• Strategies farmers use to optimise photosynthesis

  • Use greenhouses to trap heat and provide artificial light
  • Pump in carbon dioxide
  • Use fertilizers to ensure essential minerals
  • Use pesticides to control pests
• Optimising photosynthesis conditions can be costly for farmers, so they have to weigh the extra cost against the expected yield increase