Assessment and Qualifications Alliance (AQA) AS Biology Practice Exam

Temperature plays a crucial role in enzyme activity, primarily because enzymes are proteins that function based on their structural configuration. As the temperature increases, the kinetic energy of the enzyme and substrate molecules also rises, which generally leads to a higher rate of collision and interaction between them. This increase in activity continues up to an optimal temperature for each specific enzyme.

At the optimal temperature, enzymes function at their maximum efficiency. However, if the temperature continues to rise beyond this optimal point, the heat can lead to denaturation of the enzyme. This means that the enzyme's structure begins to unravel, and its active site becomes less effective or completely non-functional, leading to a decrease in activity.

Therefore, while the increased temperature initially boosts enzyme activity up to a certain threshold, extreme temperatures can be detrimental. This nuanced understanding is why the statement that increased temperature generally increases enzyme activity up to a point is accurate. It captures the essential relationship between temperature and enzyme kinetics, reflecting the balance between increased molecular motion and the risk of structural damage to the enzyme.