Which of the following is a cofactor and which is a coenzyme?
a. Fe²⁺

Verified step by step guidance

1. Understand the definitions: A cofactor is a non-protein chemical compound or metallic ion that is required for an enzyme's activity as a catalyst. Cofactors can be inorganic ions (e.g., metal ions like Fe²⁺) or organic molecules. A coenzyme, on the other hand, is a specific type of cofactor that is an organic molecule, often derived from vitamins, and assists enzymes in catalysis.
2. Analyze the given substance: Fe²⁺ is an inorganic ion, specifically a metal ion. It is not an organic molecule, so it cannot be classified as a coenzyme.
3. Determine the classification: Since Fe²⁺ is an inorganic ion and not an organic molecule, it is classified as a cofactor rather than a coenzyme.
4. Relate to biological context: Fe²⁺ often acts as a cofactor in various enzymatic reactions, such as those involving electron transfer (e.g., in cytochromes) or oxygen transport (e.g., in hemoglobin).
5. Conclude: Based on the definitions and analysis, Fe²⁺ is a cofactor, not a coenzyme.

Key Concepts

Cofactors

Cofactors are non-protein chemical compounds that assist enzymes in catalyzing reactions. They can be metal ions, such as iron (Fe²⁺), or organic molecules. Cofactors are essential for the activity of many enzymes, as they help stabilize enzyme-substrate complexes or participate directly in the chemical reaction.

Coenzymes

Coenzymes are a specific type of cofactor that are organic molecules, often derived from vitamins. They bind to enzymes and assist in the transfer of specific atoms or functional groups during biochemical reactions. Unlike cofactors, coenzymes are typically not permanently attached to the enzyme and can be reused in multiple reactions.

Enzyme Function

Enzymes are biological catalysts that speed up chemical reactions in living organisms. They lower the activation energy required for reactions to occur, allowing metabolic processes to proceed efficiently. Understanding the role of cofactors and coenzymes is crucial, as they are integral to the proper functioning of enzymes and overall metabolic pathways.