Factors That Affect Photosynthesis

• What do plants need to carry out photosynthesis?

  Light, temperature, carbon dioxide concentration, and chlorophyll
• How does 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 main limiting factors for photosynthesis?

  Light, carbon dioxide, and temperature
• In a graph showing light intensity on the x-axis, what happens to the rate of photosynthesis as light intensity increases?

  The rate of photosynthesis increases until it plateaus
• What does it mean when the graph of photosynthesis plateaus?

  Another factor, like carbon dioxide or temperature, is limiting the rate
• How does carbon dioxide concentration affect photosynthesis?

  Higher carbon dioxide concentration increases the rate of photosynthesis until it plateaus
• What happens to the rate of photosynthesis as temperature increases?

  The rate increases until enzymes denature, causing the rate to drop
• At what temperature are enzymes involved in photosynthesis fully denatured?

  About 45 degrees Celsius
• How can multiple limiting factors be represented in a graph?

  By showing different curves for different experiments
• What can be inferred if one curve in a graph shows a higher maximum rate of photosynthesis than another?

  The limiting factor was different in the two experiments
• How do farmers create optimal conditions for photosynthesis in colder climates?

  By using greenhouses to trap heat and provide artificial light
• 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 using greenhouses for farming?

  They protect plants from pests and pathogens
• What must farmers consider when implementing methods to enhance photosynthesis?

  The cost versus the expected yield from their crops
• What are the four main factors affecting photosynthesis?

  • Light intensity
  • Temperature
  • Carbon dioxide concentration
  • Amount of chlorophyll
• How do different factors limit the rate of photosynthesis?

  • Light: Increases until saturation
  • Carbon dioxide: Increases until saturation
  • Temperature: Increases then decreases due to enzyme denaturation
• How can farmers optimize conditions for photosynthesis in greenhouses?

  • Use heating to maintain temperature
  • Provide artificial lighting
  • Increase carbon dioxide levels
  • Use fertilizers and pesticides
• What happens to the rate of photosynthesis when chlorophyll levels are low?

  • The rate of photosynthesis decreases
  • Plants cannot absorb enough light energy
• How do temperature and enzyme activity relate to photosynthesis?

  • Higher temperatures increase enzyme activity
  • Excessive temperatures lead to enzyme denaturation
• Inverse square law


  I = 1/d^2

  I = light intensity

  d = distance between light source and object