The rate of photosynthesis

• What is the relationship between light intensity and the rate of photosynthesis?

  Rate increases with light intensity
• What happens to the rate of photosynthesis when there is not enough light?

  It slows down the rate of photosynthesis
• Why is light important for photosynthesis?

  It provides energy needed for photosynthesis
• What occurs to the rate of photosynthesis as light levels increase?

  It increases rapidly, then levels off
• What happens beyond a certain light intensity?

  The rate will no longer increase
• What becomes the limiting factor when light intensity is high?

  Temperature or CO₂ level
• What effect does too little carbon dioxide have on photosynthesis?

  It slows down the rate of photosynthesis
• Why is CO₂ important for photosynthesis?

  It is one of the raw materials needed
• What happens to the rate of photosynthesis as CO₂ levels increase?

  It increases, then levels off
• What must be plentiful for photosynthesis to occur efficiently?

  Light and CO₂
• What is the limiting factor when light and CO₂ are abundant?

  Temperature
• What temperature can damage enzymes needed for photosynthesis?

  About 45°C
• What usually causes temperature to be a limiting factor?

  It is too low for enzyme activity
• What happens to enzymes at high temperatures?

  They can be damaged
• What are the three main factors affecting the rate of photosynthesis?

  • Light intensity
  • Carbon dioxide levels
  • Temperature
• What are the consequences of insufficient light, CO₂, or temperature on photosynthesis?

  • Insufficient light: slows down photosynthesis
  • Insufficient CO₂: slows down photosynthesis
  • Low temperature: enzymes work slowly
  • High temperature: enzymes can be damaged