Factors Affecting the Rate of Photosynthesis

• What do plants need to carry out photosynthesis?


  Light, carbon dioxide, temperature, and chlorophyll
• How does the amount of chlorophyll affect photosynthesis?


  Less chlorophyll means less ability to carry out photosynthesis
• What can cause variations in chlorophyll levels within a plant?


  Disease, environmental stress, and lack of nutrients
• What are the three main limiting factors for photosynthesis typically referred to?


  Light, carbon dioxide, and temperature
• What does a graph of light intensity versus rate of photosynthesis show?


  As light intensity increases, the rate of photosynthesis also increases until it plateaus
• What does it mean when the graph of photosynthesis plateaus?


  It indicates that another factor is limiting photosynthesis
• How does carbon dioxide concentration affect photosynthesis?


  Higher carbon dioxide concentration increases the rate of photosynthesis until it plateaus
• How does temperature affect the rate of photosynthesis?


  Initially, the rate increases with temperature but eventually decreases as enzymes denature
• At what temperature do enzymes involved in photosynthesis become fully denatured?


  About 45 degrees Celsius
• What does it mean when a graph shows two curves for light intensity affecting photosynthesis?


  It represents two different experiments at different temperatures
• How can comparing two curves on a graph help identify limiting factors in photosynthesis?


  By observing differences in maximum rates at different conditions, we can identify which factor is limiting
• How do farmers create optimal conditions for photosynthesis in greenhouses?


  By trapping heat, providing artificial light, and increasing carbon dioxide levels
• What is one method farmers use to increase carbon dioxide levels in greenhouses?


  Pumping carbon dioxide into the greenhouse or using paraffin heaters
• What is an additional benefit of greenhouses for farmers?


  They protect plants from pests and pathogens
• Why must farmers weigh the costs of creating optimal conditions for photosynthesis?


  To determine if the extra yield justifies the additional expenses
• What are the main factors affecting the rate of photosynthesis?


  • Light intensity
  • Carbon dioxide concentration
  • Temperature
  • Amount of chlorophyll
• How do farmers use conditions to their advantage for crop growth?

  • Use greenhouses to trap heat
  • Provide artificial light
  • Pump carbon dioxide into greenhouses
  • Use fertilizers for essential minerals
  • Apply pesticides to control pests
• How do graphs help in understanding photosynthesis?


  • Show relationships between factors and photosynthesis rate
  • Indicate limiting factors when curves plateau
  • Compare effects of different conditions on photosynthesis