A Level Biology Practice Exam

What happens to an enzyme when it is denatured?

1. It becomes more effective

2. It retains its original shape

3. Its active site may be altered

4. It functions better at high temperatures

The correct answer is: Its active site may be altered

When an enzyme is denatured, its structure is fundamentally altered, particularly the shape of its active site. This change in shape results from the bond disruption within the enzyme that maintains its specific form, primarily due to factors like extreme temperature or pH. The active site is the region where substrates bind to the enzyme, and if this area is altered due to denaturation, the enzyme can no longer effectively bind with its substrates. This loss of structure leads to a decrease or complete loss of enzymatic activity, emphasizing the importance of an enzyme's shape for its function. Other options imply improvements or retention of functionality that do not accurately reflect the process of denaturation. Enzymes require their precise three-dimensional structure to function correctly, and any alteration impairs their effectiveness.