OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

What effect does an increase in kinetic energy due to higher temperatures have on enzymes?

1. It slows down their activity

2. It allows for more successful collisions

3. It has no significant impact

4. It causes them to denature

The correct answer is: It allows for more successful collisions

The correct answer highlights the relationship between kinetic energy and enzyme activity as temperature increases. Enzymes are proteins that catalyze biochemical reactions, and higher temperatures increase the kinetic energy of molecules involved in these reactions. This increase in kinetic energy leads to more frequent and effective collisions between the enzyme and its substrate. As the temperature rises, the molecules move more rapidly, which enhances the likelihood that substrates will successfully interact with enzymes. These successful collisions can lead to an increased rate of reaction, optimizing the efficiency of the enzyme. While it's true that excessively high temperatures can lead to the denaturation of enzymes, within a moderate range, the increase in kinetic energy is beneficial for promoting enzyme activity through enhanced collision rates. Therefore, the assertion that more successful collisions occur due to an increase in kinetic energy because of higher temperatures accurately reflects this relationship in enzymatic function.