Advanced Placement (AP) Biology Practice Exam

What does enzyme specificity refer to?

1. The range of reactions an enzyme can catalyze

2. The ability of an enzyme to catalyze specific substrates

3. The effect of temperature on enzyme activity

4. The maximum rate of reaction an enzyme can achieve

The correct answer is: The ability of an enzyme to catalyze specific substrates

Enzyme specificity refers to the ability of an enzyme to catalyze reactions involving specific substrates. Enzymes are highly selective catalysts, meaning they generally interact with particular molecular structures due to their unique active sites. The shape and chemical environment of the active site are complementary to the shapes of the substrates they act upon, allowing for a precise fit. This selective binding is crucial for enzymatic activity, as it ensures that enzymes facilitate only designated reactions, which helps maintain metabolic control within the cell. By recognizing the specific substrates, enzymes can efficiently lower the activation energy required for the reaction, enabling biological processes to occur under normal physiological conditions. While enzymes can exhibit some degree of versatility, this selectivity is integral to their function, distinguishing them from less specific catalytic agents.