Biology Regents Practice Exam

What is the primary role of enzymes in biological systems?

1. To store genetic information

2. To catalyze biochemical reactions

3. To transport substances across cell membranes

4. To provide structural support to cells

The correct answer is: To catalyze biochemical reactions

Enzymes play a crucial role in biological systems primarily by acting as catalysts that speed up biochemical reactions. They facilitate reactions by lowering the activation energy needed for the reaction to occur, which allows the reaction to proceed more quickly and efficiently without being consumed in the process. This catalytic action is essential in various biological processes, including digestion, metabolism, and DNA replication. Enzymes are specific in their action, meaning each enzyme typically targets a particular substrate to catalyze a specific reaction. This specificity is critical for maintaining the proper functioning of cellular processes. By aiding in the transformation of substrates into products, enzymes ensure that metabolic pathways can operate efficiently, which is vital for sustaining life. The other options point to different functions that cells and biological systems perform. Genetic information is stored in DNA and not by enzymes. While some proteins can assist with transport across cell membranes, this is not the primary function of enzymes. Providing structural support is typically performed by different types of proteins, such as collagen or cytoskeletal elements, rather than by enzymes. Thus, the catalytic role of enzymes is central to the functioning of biological systems, highlighting why this is the correct answer.