Heat stress is a major environmental factor limiting crop yield globally by affecting photosynthesis.
A decrease in the light-dependent reaction of photosynthesis leads to a decrease in the light-independent reaction. Explain why.
The enzyme rubisco catalyses the first step of the light-independent reaction. Explain how a decrease in rubisco activity reduces the rate of photosynthesis.
State the precise site of rubisco activity within a photosynthetic cell.
Scientists investigated the effect of temperature on the activity of two isolated enzymes from wheat leaves: rubisco and rubisco activase (an enzyme required to activate rubisco). Their results are shown in Figure 1 and Figure 2 below.
The scientists concluded that heat stress reduces the rate of photosynthesis in wheat leaves by decreasing the activity of rubisco activase, which in turn limits rubisco activity.
Evaluate this conclusion using the information in the graphs and your biological knowledge.