Cell Receptor

A receptor is a molecule found on the surface of the cell. This receptor’s main task is to receive chemical signals from the external environment of the cell. The signals received by the cells “instruct” the cell to perform a specific function—the cell could allow certain molecules to enter or exit the membrane, initiate the process of cell division, or to die. Receptors are basically made up of protein molecules, which are embedded in the plasma membrane (these receptors are called “cell surface receptors”) or in the cytoplasm or nucleus of the cell (these receptors are “nuclear receptors”), to which on or more kinds of signaling molecules can attach themselves to. A molecule that attaches itself to a receptor is then called a ligand, which can be either a peptide or a small molecule (can be a hormone, a neurotransmitter, a pharmaceutical drug, or even a toxin). There are different receptor types found in the surface of a typical cell, and each f these types us is connected to a very specific biochemical pathway. Each type of receptor will only recognize and bind to specific ligand shapes—the selecting binding of a specific ligand to the corresponding receptor activates or inhibits a certain pathway. The binding of ligand and receptor stabilizes a specific receptor conformation, and is associated with the loss or gain or certain protein activities. But there are some antagonistic ligands that simply block the receptors without inducing any kind of response within the cell. Ligands typically induce change in the cellular environment. When it comes to molecules of pharmaceutical drugs, there are four theories that are used by medical professionals. The first is the occupatin theory, which states: “drug effect is directly proportional to the number of receptors occupied.” There are also the Ariens and Stephenson, rate, and induced fit theories. This category contains scientific information about cellular receptors, which receive chemical signals from the external environment of the cells.