BRAINCAKETemperature as a Limiting Factor
Temperature affects photosynthesis mainly through enzymes. The light-independent reaction (Calvin cycle) is catalysed by enzymes such as rubisco, so it is the stage most affected by temperature. The light-dependent reaction is less affected, because absorbing light is a physical process.
At low temperatures, molecules have little kinetic energy, so there are few successful collisions between enzymes and substrates and few enzyme-substrate complexes form. The rate of photosynthesis is low. As the temperature rises, the rate increases up to an optimum.
Above the optimum the rate falls, for two reasons:
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Key terms in this lesson
- rubisco
- The enzyme that catalyses the fixation of carbon dioxide onto ribulose bisphosphate (RuBP) in the Calvin cycle; it is the rate-limiting enzyme of photosynthesis.
More in Energy for Biological Processes
- Calvin Cycle
- Limiting Factors of Photosynthesis
- Light Intensity as a Limiting Factor
- Carbon Dioxide Concentration as a Limiting Factor
- Interpreting Limiting Factor Graphs
- Effect of Limiting Factors on the Calvin Cycle
- Uses of Triose Phosphate
- Investigating the Rate of Photosynthesis
All 17 lessons in Energy for Biological Processes · All AQA A-level Biology topics