Guard cells contain chloroplasts, whereas epidermal cells do not contain chloroplasts. State one further visible difference in Fig. 8.1 between guard cells and epidermal cells.
During stomatal closure: state exactly where abscisic acid (ABA) binds.
During stomatal closure: identify the ion that moves from the guard cells to the epidermal cells by diffusion.
During stomatal closure: compare the water potential of the guard cells with that of the epidermal cells.
During stomatal closure: describe how the volume of the guard cells changes.
State why sodium hydrogencarbonate solution was used.
Calculate the mean rate of oxygen production for tube A over the 20 minutes of the experiment. Show how you obtained your answer.
Compare the findings for tubes A and B.
Explain the outcome for tube C.
Suggest which factor, that may influence the rate of photosynthesis, was not allowed for in this experiment.
Fig. 8.3 illustrates the link between the light-dependent and light-independent reactions inside a chloroplast. Name substances X and Y in Fig. 8.3.