What is a specific region of an enzyme where a substrate binds and the chemical reaction occurs

The correct answer is an active site.

The active site, in biology, refers to the region of an enzyme where the molecules of substrate combine and goes through a chemical reaction. The active site comprises of the residues, which produce temporary bonds with the binding site (substrate) and residues that catalyze a reaction of that substrate, that is, the catalytic site.

Active site is a specific region of an enzyme where a substrate binds and the chemical reaction occurs.

Explanation:

The active site is the region of an enzyme where substrate molecules bind and undergo a chemical reaction.

It consists of two sites:

Binding site:

It consists of residues that form temporary bonds with the substrate.

Catalytic site:

It consists of residues that catalyze a reaction of that substrate.