Question

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

Explanation:

The lock - and - key mechanism is a model for enzyme - substrate interaction. In this model, the enzyme (lock) has a specific active site that fits the substrate (key) precisely. Reactant and substrate are not terms used in this specific binding mechanism in the context of this model. Substrate and product are related through a reaction catalyzed by an enzyme, but their relationship is not described by the lock - and - key binding. Reactant and product are also not bound in this way.

Answer:

enzyme and substrate