Receptors

__ **Biochemical Receptors** __    __**What is a biochemical receptor?**__ A biochemical receptor is a molecule which under certain conditions (such as being in the body) will bind to a specific substance to activate some kind of response. Theses specific substances are chemical molecules and as they bind to receptors are given the name ligands. A biochemical receptor molecule is a protein which means that it is predominantly made out of the elements: carbon, hydrogen, oxygen, nitrogen and sulfur. **__What is a Ligand?__** As mentioned above a ligand is a chemical molecule which binds to a biochemical receptor. However each kind of biochemical receptor is unique and will only bind to a specific ligand, thus a ligand can only bind to one kind of receptor and not to all. Therefore there are many kinds of ligands (so numerous not all have been discovered). **__Where are biochemical receptors found?__** All living things are made out of small, microscopic complexes called cells. The outer most layer of a cell is called the cell membrane and it is at this layer where the cell articulates with the outside environment. A biochemical receptor will start outside the cell membrane and penetrate all the way through it just to the inside of the cell. Each cell has many different kinds of receptors. **__The response__** Once a ligand has bound to a receptor it is only just the beginning of the process. Signals (in the for of chemical molecules) are sent throughout the cell from the receptor. These signals then causes the some kind of response from the cell. The response will vary from cell to cell and also depends what kind of receptor was activated. **__Why are biochemical receptors important in immunogenicity?__** Biochemical receptors are an integral part of the immune system and as immunogenicity relies on the immune system it is therefor dependent on biochemical receptors. The biochemical receptors involved in the immune system are referred to as immune receptors as they cause a response in the immune system. (Marieb and Hoehn) **Picture:** The picture opposite shows a ligand binding to a receptor and causing a response Toll-like Receptors Dentritic Cells Home Contributed by Christopher Sutton