Enzymes are biological ________ by binding to _______.

Enzymes are biological ________ by binding to _______.

• A. Catalysts; substrates (correct)
• B. Regulators; products
• C. Receptors; hormones
• D. Structural proteins; enzymes

Answer: (A)

Enzymes act as biological catalysts by binding to substrates at their active site, forming an enzyme-substrate complex that lowers the activation energy needed for the reaction and speeds it up. After the reaction occurs, the products are released and the enzyme is free to catalyze more reactions. The other ideas describe different roles—instead of catalyzing reactions, regulators would imply control over processes, receptors bind signaling molecules like hormones, and structural proteins provide support—so the core function described here best matches how enzymes work.

Enzymes act as biological catalysts by binding to substrates at their active site, forming an enzyme-substrate complex that lowers the activation energy needed for the reaction and speeds it up. After the reaction occurs, the products are released and the enzyme is free to catalyze more reactions. The other ideas describe different roles—instead of catalyzing reactions, regulators would imply control over processes, receptors bind signaling molecules like hormones, and structural proteins provide support—so the core function described here best matches how enzymes work.