* Primary metabolites are directly involved in normal growth, development, and reproduction of an organism. They are essential for basic life functions.

* Secondary metabolites are not directly involved in these processes. They are often produced as byproducts of metabolism or have more specialized roles, such as defense against pathogens or attracting pollinators.

Enzymes are essential for all biological processes:

* Catalyzing reactions: Enzymes speed up chemical reactions within cells, enabling them to function properly.

* Essential for metabolism: Metabolism, the sum of all chemical reactions in an organism, relies heavily on enzymes.

Examples of primary metabolites:

* Amino acids

* Carbohydrates

* Lipids

* Nucleic acids

Examples of secondary metabolites:

* Antibiotics

* Toxins

* Pigments

* Alkaloids

Since enzymes are essential for fundamental life processes, they are classified as primary metabolites.