Understanding Limiting Factors in Photosynthesis

Objectives

• Interpret graphs to determine limiting factors in photosynthesis.
• Explain how greenhouses are used to increase the rate of photosynthesis.

Key Concepts

• Photosynthesis Equation: Light energy is absorbed by chlorophyll, allowing carbon dioxide and water to react and form glucose. Oxygen is also produced.

Limiting Factors in Photosynthesis

• Light Intensity: Initially, increasing light intensity increases the rate of photosynthesis, indicating it is a limiting factor.
• Carbon Dioxide Concentration:
  • If increased, and the rate increases, CO2 was the limiting factor.
  • If further increase does not change the rate, CO2 is no longer the limiting factor.
• Temperature:
  • If increasing temperature increases the rate, temperature was the limiting factor.
  • If increased too much, enzymes denature, reducing the rate of photosynthesis.
• Amount of Chlorophyll: While less controllable, it can also be a limiting factor.

Greenhouses and Photosynthesis

• Purpose: Used to exploit limiting factors to increase photosynthesis rate and crop yield.
• Methods:
  • Light and heat are provided to the greenhouse.
  • Extra carbon dioxide is supplied.
  • Sometimes oil burners are used to release heat and CO2 simultaneously.
• Cost Consideration: The expense of enhancing greenhouse conditions must be justified by increased crop yield.

Additional Resources

• Revision Workbook: Contains questions on limiting factors, available via a link provided in the lesson.

By mastering these concepts, you should be able to interpret relevant graphs and explain the role of greenhouses in boosting photosynthesis.