Coenzymes are the small, organic nonprotein parts of an enzyme that are involved in catalysis. Which of the following statements accurately describes the characteristics and functions of coenzymes? (Select all that apply)
I. Coenzymes bind permanently to enzymes and cannot be released after the reaction.
II. Coenzymes often serve as carriers of electrons, atoms, or functional groups in enzymatic reactions.
III. Coenzymes are typically derived from vitamins and play essential roles in enzyme activity.
IV. Coenzymes do not alter the enzyme’s overall structure but assist in facilitating the reaction.

• A. II and III
• B. III and IV
• C. I and IV
• D. II, III, and IV

Answer: (D)