Question

2.3.2 quiz: proteins and enzymes review the results of the following experiment. which hypothesis most likely explains the results at 60°c and 70°c? a. the enzyme is only effective at very high temperatures. b. the substrate has been used up because of the high temperature. c. the enzyme has changed shape because of the high temperature. d. the bonds in the substrate are weakened at high temperatures.

Explanation:

Enzymes are proteins and their activity is temperature - dependent. High temperatures can denature enzymes, changing their shape and reducing their activity. At 60°C and 70°C, the most likely reason for the drop in enzyme activity is that the high temperature has caused the enzyme to change shape (denaturation). Option A is incorrect as the graph shows peak activity around 40°C, not high temperatures. Option B is not likely as the drop is due to enzyme - related factors rather than substrate depletion. Option D focuses on the substrate bonds, but the main issue at these temperatures is enzyme denaturation.

Answer:

C. The enzyme has changed shape because of the high temperature.