Biology Help Please

Question

1. A biologist investigating enzyme function plotted the activity of a particular enzyme (y-axis) versus pH (x-axis). Experiment A was performed at 10 degrees C, and experiment C at 100 degrees C. Experiments A, B, and C all used the same enzyme, they simply tested the enzyme’s activity at different temperatures. Using your knowledge of enzyme activity, answer the questions based on the graph.

a) Explain why lines A and B are so different.

b) Why is there no hill in the middle of line C?

c) After conducting experiment C, the investigator cools the reaction vessel to 30o C and repeats the experiment using the exact same enzyme (not just the same type of enzyme, but the very same enzyme that was used in experiment C). In the space provided below, draw the shape of the line that you would expect to see on the graph for this new experiment.

Answer 1

Without knowing the conditions for B it is impossible to know exactly what might be happening. If the temp was intermediate between 10Cº and 100Cº then the enzyme might be sensitive to the higher values. If the temp was 10Cº it might have been that the enzyme was somewhat denatured by age, time outside of the freezer etc. C appears to be completely denatured at 100Cº (which is likely unless it was from a thermophilic organism). : )

If the experiment was repeated at 100Cº with the same sample of enzyme the line will stay flat, as there is not an enzymatic activity.