Final answer:
Hormones are classified into three main chemical categories: lipid-derived, amino acid-derived, and peptide hormones, each distinguished by their ability to cross cell membranes and the receptors they bind.
Step-by-step explanation:
There are three main chemical classes of hormones distinguished by structure and function: lipid-derived (steroid) hormones, amino acid-derived hormones, and peptide (and protein) hormones. A key factor that distinguishes lipid-derived hormones is their ability to diffuse across plasma membranes, which is not a characteristic of amino acid-derived and peptide hormones.
Lipid-derived hormones like testosterone are structurally similar to cholesterol and can move through cell membranes easily to bind intracellular receptors. Amino acid-derived hormones, such as epinephrine, are made from single amino acids and bind to receptors on the cell's surface. Peptide hormones, like insulin, consist of chains of amino acids and interact with cell surface receptors to elicit cellular responses.