Biology- limiting factors

• Limiting factor in photosynthesis

  Factor that limits the rate of photosynthesis
• Interpreting graphs to determine the limiting factor in photosynthesis

  1. Observe the rate of photosynthesis as different factors are increased

  2. Identify the factor that causes the rate to stop increasing, as that is the limiting factor
• Factors that limit photosynthesis

  • Light intensity
  • Carbon dioxide concentration
  • Temperature
  • Amount of chlorophyll in leaves
• Increasing light intensity


  Rate of photosynthesis increases initially
• At a certain point, light intensity is no longer the limiting factor</b>
• Increasing carbon dioxide concentration

  Rate of photosynthesis increases
• Carbon dioxide concentration was the limiting factor
• Increasing carbon dioxide concentration further

  Rate of photosynthesis does not increase
• Carbon dioxide concentration was no longer the limiting factor
• Increasing temperature


  Rate of photosynthesis increases
• Temperature was a limiting factor
• Increasing temperature too much causes enzymes to denature and the rate of photosynthesis to fall
• How greenhouses are used to increase the rate of photosynthesis

  • Provide extra light
  • Provide extra heat
  • Provide extra carbon dioxide
• The extra cost of using greenhouses has to be justified by the increase in crop yield