Photo AI
The activity of an enzyme is A - VCE - SSCE Biology - Question 2 - 2012 - Paper 1
Question 2
The activity of an enzyme is A. decreased by the presence of an inhibitor. B. unaffected by the pH of the cytosol of a cell. C. reduced at very low temperatures due ... show full transcript
Worked Solution & Example Answer:The activity of an enzyme is A - VCE - SSCE Biology - Question 2 - 2012 - Paper 1
Step 1
A. decreased by the presence of an inhibitor.
Answer
Enzyme inhibitors are molecules that bind to an enzyme and decrease its activity. They can do so by following several mechanisms, such as competitive inhibition, where the inhibitor competes with the substrate for the active site, or non-competitive inhibition, where the inhibitor binds to a different site on the enzyme. In either case, the presence of an inhibitor typically results in a decreased rate of the reaction catalyzed by the enzyme.
Step 2
B. unaffected by the pH of the cytosol of a cell.
Answer
This statement is incorrect. The activity of an enzyme is highly dependent on the pH of its environment. Each enzyme has an optimum pH at which it is most active. Deviations from this optimal pH can lead to decreased activity or denaturation of the enzyme.
Step 3
C. reduced at very low temperatures due to denaturation.
Answer
This statement is partially incorrect. While enzyme activity typically decreases at very low temperatures, it is not due to denaturation. Denaturation generally occurs at high temperatures or extreme pH levels. At low temperatures, enzymes may become less flexible, leading to reduced activity due to decreased molecular motion, but they do not denature.
Step 4
D. increased as the temperature rises above the enzyme’s optimum temperature.
Answer
This statement is also incorrect. While enzyme activity may increase with temperature up to the optimum level, beyond this point, the structure of the enzyme can denature, leading to a rapid decrease in activity. Therefore, enzyme activity does not continually increase as temperature rises beyond the optimum level.