Question

2
a group of students completed two experiments. their notes are below:
experiment 1:

• hydrogen peroxide was poured on a slice of raw potato.
• the peroxide bubbled vigorously.
• the peroxide was broken down into water and oxygen.

experiment 2:

• a slice of raw potato was heated and then hydrogen peroxide was poured on it.
• there was no visible reaction.

which statement explains the results of these experiments?
a heating the potato had no effect on the potato enzymes.
b heating the potato caused the hydrogen peroxide to evaporate, so the reaction did not occur.
c heating the potato caused the potato enzymes to release the water and oxygen from the hydrogen peroxide.
d heating the potato caused a shape change in the potato enzymes, so they could no longer function properly.

Explanation:

• Option A: Heating usually affects enzymes (like denaturing them), so this is incorrect.
• Option B: The experiment involves the potato's enzymes acting on peroxide; evaporation isn't the reason for no reaction, so B is wrong.
• Option C: Heating would likely inhibit enzyme function, not cause them to release products as described, so C is incorrect.
• Option D: Enzymes (like catalase in potato) can be denatured by heat, changing their shape (tertiary structure) and making them non - functional. In Experiment 1, the enzyme was active (peroxide bubbled as it was broken down). In Experiment 2, heating the potato denatured the enzyme, so no reaction occurred. This matches the results.

Answer:

D. Heating the potato caused a shape change in the potato enzymes, so they could no longer function properly.