The graph below shows the results of two experiments, A and B. In both cases the uptake of potassium ions into the roots of young plants was measured. Roots were thoroughly washed in pure water before the plants were added to solutions containing potassium ions. Experiment A was carried out at 25 °C and experiment B at 0 °C. In experiment A, potassium cyanide was added to the solution surrounding the roots aft er 90 minutes (see arrow in figure). Potassium cyanide is an inhibitor of respiration.

a. Suggest why the roots were thoroughly washed in pure water before the experiments.

b. Describe the results of experiment A over the first 80 minutes of the experiment.

c. Describe the results of experiment B.

d. Explain the results described in b and c above.

e. Describe the effect of adding potassium cyanide in experiment A.

f. Explain the effect of adding potassium cyanide in experiment A.

Transcribed Image Text:

potassium cyanide added experiment A 25°C 0°C experiment B 0 20 40 60 80 100 120 Time / minutes Potassium uptake