Organic Chemistry MCAT Practice Exam

What type of reaction can hydrolysis catalyze in biological systems?

1. Oxidation

2. Condensation

3. Hydrogenation

4. Activation or inactivation of enzymes

The correct answer is: Activation or inactivation of enzymes

Hydrolysis is a chemical reaction that involves the breaking down of a compound by the addition of water. In biological systems, hydrolysis is crucial for the activation and inactivation of various biomolecules, especially enzymes. This process often alters the enzyme's structure and, consequently, its activity. For example, proenzymes (inactive enzyme precursors) require hydrolysis for their activation. Upon the cleavage of specific peptide bonds within the proenzyme, the enzyme becomes active and can catalyze biochemical reactions. Similarly, certain enzymes can be inactivated by hydrolysis, which breaks the necessary bonds for their function. While oxidation, condensation, and hydrogenation reactions are important biochemical processes, they do not directly pertain to the role of hydrolysis in biological systems. Each of these processes has its mechanism and implications that do not primarily involve the addition of water to catalyze the formation or breakdown of molecules in the same way hydrolysis does.