The special shape on an enzyme where the substrate binds to it is the _____.

• A. active site
• B. regulatory domain
• C. cofactor pocket
• D. allosteric site

Answer: (A)

Verified step by step guidance

1. Understand the role of enzymes in biochemical reactions: Enzymes are biological catalysts that speed up reactions by lowering the activation energy required for the process.
2. Learn about the substrate: The substrate is the molecule upon which the enzyme acts. It binds to a specific region on the enzyme to undergo a chemical transformation.
3. Define the active site: The active site is the specific region on the enzyme where the substrate binds. It has a unique shape and chemical properties that complement the substrate, allowing for precise binding and catalysis.
4. Differentiate between the options: The regulatory domain is involved in controlling enzyme activity, the cofactor pocket binds non-protein molecules that assist enzyme function, and the allosteric site is a region where molecules bind to regulate enzyme activity indirectly. None of these are the primary binding site for the substrate.
5. Conclude that the correct answer is the active site, as it is the special shape on the enzyme where the substrate directly binds to undergo a reaction.