What is the difference between covalent receptor-ligand interaction and noncovalent binding?

• A. Covalent binding forms a chemical bond leading to permanent or long-lasting interaction; noncovalent binding is reversible.
• B. Covalent binding is weaker than noncovalent.
• C. Covalent binding occurs only with enzymes.
• D. Covalent binding always blocks receptor entirely.

Answer: (A)