Question

Figure 11.10 shows the effect of light on the rate of photosynthesis. Based on the graph, answer the following questions: 

1. At which point/s (A, B or C) in the curve is light a limiting factor? 
2. What could be the limiting factor/s in region A? 
3. What do C and D represent on the curve?

Answer 1

(a) In region A, light is a constraint. The factor in the shortest supply, known as the limiting factor, will restrict the rate of a process. The rate of reaction will alter if a limiting factor changes in strength.

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(b) In region A, temperature, light, and carbon dioxide content could be limiting variables.

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(c) C stands for light saturation. Here, the limitation is no longer light. Temperature or the amount of carbon dioxide present could be the limiting factor in this case. The letter D stands for the point at which the carbon dioxide saturation maximum that the plant needs for photosynthesis has been attained.