AP BIOLOGY

Detailed explanation-1: -Receptors come in many types, but they can be divided into two categories: intracellular receptors, which are found inside of the cell (in the cytoplasm or nucleus), and cell surface receptors, which are found in the plasma membrane.

Detailed explanation-2: -There are two main types of ligands: ligands that bind to receptors inside the cell, called intracellular ligands, and ligands that bind to receptors outside the cell, called extracellular ligands.

Detailed explanation-3: -Intracellular receptors require ligands that are membrane permeable and include receptors for steroid hormones, lipophilic vitamins, and small molecules such as nitric oxide and hydrogen peroxide.

Detailed explanation-4: -Ion channel-linked receptors bind a ligand and open a channel through the membrane that allows specific ions to pass through. G-protein-linked receptors bind a ligand and activate a membrane protein called a G-protein, which then interacts with either an ion channel or an enzyme in the membrane.