Advanced Placement (AP) Biology Practice Exam

How does temperature affect enzyme kinetics?

1. Higher temperatures always decrease reaction speed.

2. Lower temperatures generally increase reaction speed.

3. Increasing temperature increases the speed of the reaction.

4. Temperature has no effect on enzyme reactions.

The correct answer is: Increasing temperature increases the speed of the reaction.

Increasing temperature typically leads to an increase in the speed of enzyme-catalyzed reactions due to a rise in kinetic energy of the molecules involved. As temperature increases, molecules move faster, leading to more frequent and forceful collisions between enzymes and substrates. This heightened molecular motion can promote the formation of enzyme-substrate complexes, thus accelerating the reaction rate. However, it's important to note that this relationship does not extend indefinitely. While moderate increases in temperature generally enhance reaction rates, extreme temperatures can lead to enzyme denaturation, resulting in a loss of enzymatic activity. Enzymes have optimal temperature ranges where their activity is maximized. Therefore, while increased temperatures initially boost reaction speed, there are limits beyond which enzyme functionality may be compromised. The understanding that increased temperature correlates with increased kinetic energy is fundamental to grasping how enzymes operate in biochemical reactions. Enzymes act as catalysts, and their efficiency is often reflected in the rates of the reactions they facilitate, showcasing the critical balance between temperature, enzymatic activity, and reaction speed.