A Level Biology Practice Exam

The enzyme-product complex is formed at which point in an enzymatic reaction?

1. Before the substrate binds

2. After the product is released

3. During substrate conversion at the active site

4. When the enzyme is denatured

The correct answer is: During substrate conversion at the active site

The enzyme-product complex is indeed formed during substrate conversion at the active site. In an enzymatic reaction, the substrate first binds to the enzyme at its active site, forming the enzyme-substrate complex. This binding is a crucial step that allows the enzyme to catalyze the transformation of the substrate into the product. Once the reaction occurs, the product is formed still associated with the enzyme, leading to the enzyme-product complex. This complex is a temporary, transitional state before the product is released, and it highlights the essential role of the active site in facilitating the conversion of substrate to product.