Question

multiple choice question

which of the following is not a cofactor?

metal ion
organic molecule
coenzyme
oxygen

Explanation:

Define cofactors and their types

Cofactors are non-protein chemical compounds or metallic ions that are required for an enzyme's activity as a catalyst. They can be broadly classified into inorganic ions (such as metal ions) and organic molecules (which, when loosely bound, are specifically called coenzymes).

Evaluate the given options

• Metal ion: Inorganic cofactor (e.g., \(Zn^{2+}\), \(Fe^{2+}\)).
• Organic molecule: Organic cofactor (broad category).
• Coenzyme: A specific type of organic cofactor (e.g., vitamins, NAD+).
• Oxygen: A diatomic gas molecule (\(O_2\)) that acts as a terminal electron acceptor in aerobic respiration or a substrate/reactant in specific oxidation reactions, but is not classified as an enzymatic cofactor.

Answer:

• Metal ion
• Organic molecule
• Coenzyme
• Oxygen (Correct answer)