- A An active enzyme ready to catalyze reactions
- B An inactive enzyme precursor
- C A type of coenzyme assisting enzyme function
- D A regulatory protein controlling gene expression
Correct answer: B. An inactive enzyme precursor
Explanation: Zymogens (proenzymes) are inactive enzyme precursors activated by cleavage of a peptide. Example: pepsinogen is converted to pepsin by HCl in the stomach.
Concept context
Carbohydrates, proteins, lipids, nucleic acids, and enzyme kinetics. Essential foundation for understanding metabolism.