Question

which two substances bind using a lock-and-key mechanism?
○ enzyme and substrate
○ reactant and substrate
○ substrate and product
○ reactant and product

Explanation:

The lock - and - key mechanism is a model used to describe the interaction between enzymes and their substrates. Enzymes have an active site with a specific shape that is complementary to the shape of the substrate, just like a lock and a key. Reactants and substrates are not a pair that uses this mechanism (reactants are more general and the lock - and - key is specific to enzyme - substrate). Substrates are converted to products, and they do not bind with each other via the lock - and - key mechanism. Reactants and products are related by a chemical reaction, not by the lock - and - key binding. So the correct pair is enzyme and substrate.

Answer:

A. enzyme and substrate