Question

what is the next step in the process after a substrate enters the active site of an enzyme?
the chemical reaction occurs.
new substances called products are formed.
the enzyme and the substrate bind to form the enzyme - substrate complex.
the enzyme and the products bind to form the enzyme - products complex.

Explanation:

When a substrate enters the active site of an enzyme, the first thing that occurs is the binding of the enzyme and the substrate to form the enzyme - substrate complex. This binding is based on the complementary shape and chemical properties of the enzyme's active site and the substrate. The chemical reaction occurs after the complex is formed. New substances (products) are formed as a result of the chemical reaction. The enzyme - products complex is formed during the reaction and then the products are released (the enzyme is not bound to the products in a complex in the long - term as it is a catalyst and is regenerated).

Answer:

The enzyme and the substrate bind to form the enzyme - substrate complex.