Which statement correctly describes cofactors and coenzymes?

Which statement correctly describes cofactors and coenzymes?

• A. Cofactors are organic cofactors.
• B. Cofactors are always proteins.
• C. Cofactors can be inorganic metal ions.
• D. Coenzymes are inorganic cofactors.

Answer: (C)

Cofactors are non-protein helpers that enzymes need to function, and they come in two broad forms: inorganic metal ions and organic molecules. The inorganic metal ions, such as Mg2+, Zn2+, and Fe2+, can participate directly in the catalytic process or help position substrates and stabilize charges during the reaction. That’s why cofactors can be inorganic metal ions—the statement capturing this is correct. Coenzymes are the organic members of the cofactors, often derived from vitamins, and they carry chemical groups or electrons between reactions (for example, NAD+ and FAD shuttle electrons, while coenzyme A carries acyl groups). Because coenzymes are organic, the claim that coenzymes are inorganic cofactors is not correct. Similarly, cofactors are not always proteins, and cofactors aren’t simply organic cofactors; the inorganic option shows why cofactors can include non-protein metal ions.

Cofactors are non-protein helpers that enzymes need to function, and they come in two broad forms: inorganic metal ions and organic molecules. The inorganic metal ions, such as Mg2+, Zn2+, and Fe2+, can participate directly in the catalytic process or help position substrates and stabilize charges during the reaction. That’s why cofactors can be inorganic metal ions—the statement capturing this is correct.

Coenzymes are the organic members of the cofactors, often derived from vitamins, and they carry chemical groups or electrons between reactions (for example, NAD+ and FAD shuttle electrons, while coenzyme A carries acyl groups). Because coenzymes are organic, the claim that coenzymes are inorganic cofactors is not correct. Similarly, cofactors are not always proteins, and cofactors aren’t simply organic cofactors; the inorganic option shows why cofactors can include non-protein metal ions.