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 that is required for a protein's biological activity. Cofactors can be metal ions or organic molecules. A coenzyme is a specific type of cofactor that is an organic molecule, often derived from vitamins, and is necessary for enzyme function.
2. Identify the given substance: Fe^{2+} is an iron ion, which is a metal ion.
3. Determine the classification: Since Fe^{2+} is a metal ion, it falls under the category of cofactors, not coenzymes.
4. Recall examples: Common metal ion cofactors include Fe^{2+}, Mg^{2+}, Zn^{2+}, and Cu^{2+}. Coenzymes, on the other hand, include organic molecules like NAD^+, FAD, and coenzyme A.
5. Conclude: Fe^{2+} is a cofactor because it is a metal ion, not an organic molecule, and therefore not a coenzyme.

Key Concepts

Cofactors

Cofactors are non-protein chemical compounds that assist enzymes in catalyzing reactions. They can be metal ions, like 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 for grasping how enzymes function and the importance of these molecules in biochemical pathways.