Heat stress decreases the light-dependent reaction of photosynthesis.

Explain why this leads to a decrease in the light-independent reaction.

Another effect of heat stress is a decrease in the activity of the enzyme rubisco. A decrease in the activity of an enzyme means that the rate of the reaction it catalyses becomes slower.

A decrease in the activity of the enzyme rubisco would limit the rate of photosynthesis.

Explain why.

Where precisely is rubisco found in a cell?

Scientists investigated the effect of temperature on the activity of two enzymes isolated from the leaf cells of cotton plants. • Rubisco • Rubisco activase – an enzyme that activates rubisco

Figure 1 and Figure 2 show their results.

The scientists concluded that heat stress reduces the activity of rubisco in plant leaves by affecting rubisco activase.

Use all the information to evaluate their conclusion.