Advanced Placement (AP) Biology Practice Exam

Which factor is known to affect enzyme function during experiments?

1. Substrate type

2. Environmental temperature

3. pH of the solution

4. Concentration of products

The correct answer is: Environmental temperature

The choice of environmental temperature as a factor affecting enzyme function is based on the understanding that temperature impacts the kinetic energy of molecules. As temperature increases, enzyme and substrate molecules move more rapidly, which typically increases the rate of reaction up to a certain point. Each enzyme has an optimal temperature range where it functions most effectively. If the temperature is too low, the enzyme activity slows down, while excessive heat can denature the enzyme, altering its three-dimensional structure and active site, leading to a loss of function. While substrate type, pH of the solution, and concentration of products can influence enzyme activity, the direct relationship between temperature and kinetic energy makes it a critical factor in enzyme experiments. The optimal temperature at which an enzyme operates best is fundamental to understanding how enzymes work in biochemical processes.