AP BIOLOGY

Detailed explanation-1: -A molecule that binds to a receptor is called a ligand and can be a protein, peptide (short protein), or another small molecule, such as a neurotransmitter, hormone, pharmaceutical drug, toxin, calcium ion or parts of the outside of a virus or microbe.

Detailed explanation-2: -A ligand that can bind to and alter the function of the receptor that triggers a physiological response is called a receptor agonist. Ligands that bind to a receptor but fail to activate the physiological response are receptor antagonists.

Detailed explanation-3: -Cell-surface receptors come in three main types: ion channel receptors, GPCRs, and enzyme-linked receptors. When a ligand binds an ion channel receptor, a channel through the plasma membrane opens that allows specific ions to pass through.

Detailed explanation-4: -There are three general categories of cell-surface receptors: ion channel-linked receptors, G-protein-linked receptors, and enzyme-linked receptors.

Detailed explanation-5: -A ligand-binding site is a place of chemical specificity and affinity on protein that binds or forms chemical bonds with other molecules and ions or protein ligands. The affinity of the binding of a protein and a ligand is a chemically attractive force between the protein and ligand.