American Society for Clinical Pathology (ASCP) Histotechnologist Practice Test

In the classification of hydrolases, what is the primary action on substrates?

1. Condensation

2. Reduction

3. Hydrolysis

4. Dehydration

The correct answer is: Hydrolysis

Hydrolases are a class of enzymes that primarily function to catalyze the hydrolysis of chemical bonds. The key action they perform is the addition of water (H2O) to a substrate, resulting in the breaking of those bonds. This process is essential in various biological systems, facilitating the breakdown of larger biomolecules into smaller, more manageable units. This is fundamental in physiological processes such as digestion, where complex carbohydrates, proteins, and lipids are broken down into their monomeric form (like glucose, amino acids, and fatty acids) for absorption and utilization by the body. The other options refer to different types of enzymatic reactions. Condensation involves the joining of two molecules with the release of water, which is the opposite of what hydrolases do. Reduction refers to a chemical reaction involving the gain of electrons or hydrogen, which is not a primary action of hydrolases. Dehydration typically refers to the removal of water from a substance, again contrary to the hydrolytic action of these enzymes. Therefore, hydrolysis is the defining characteristic of hydrolases and underscores their significance in metabolic and biochemical processes.