Most enzymes are which type of molecule?

Most enzymes are which type of molecule?

• A. Nucleic acids
• B. Proteins
• C. Carbohydrates
• D. Lipids

Answer: (B)

Enzymes are most commonly proteins because their amino acid sequences fold into precise three‑dimensional shapes that create an active site perfectly suited to bind a substrate. This specific geometry, along with the diverse chemical functionalities of amino acid side chains, lets proteins stabilize transition states and participate directly in the chemical steps of a reaction, dramatically lowering the activation energy needed. While some RNA molecules can act as catalysts—ribozymes—these are much less common, so the majority of enzymes are protein-based. Nucleic acids, carbohydrates, and lipids don’t typically serve as the main catalytic agents in standard cellular reactions.

Enzymes are most commonly proteins because their amino acid sequences fold into precise three‑dimensional shapes that create an active site perfectly suited to bind a substrate. This specific geometry, along with the diverse chemical functionalities of amino acid side chains, lets proteins stabilize transition states and participate directly in the chemical steps of a reaction, dramatically lowering the activation energy needed. While some RNA molecules can act as catalysts—ribozymes—these are much less common, so the majority of enzymes are protein-based. Nucleic acids, carbohydrates, and lipids don’t typically serve as the main catalytic agents in standard cellular reactions.