The processing requirements include successful completion of: 1  The application process, which includes a background and polygraph examination, a medical examination, a physical fitness evaluation, and a written examination; 2  24-26 weeks of intensive Academy training.
The cell membrane, being exposed to the outside environment, is an important site of cell-cell communication. As such, a large variety of protein receptors and identification proteins, such as antigens, are present on the surface of the membrane.
One cell may have a receptor in its membrane and when it binds to a matching ligand on a neighboring cell the receptor performs some action. Typically this action is to take an existing protein and modify it in some way to either activate or deactivate it.A good example of this is a tyrosine kinase receptor.henever a ligand binds to the receptor it causes the receptor to produce more of the expressed protein. This protein can be of any type except another receptor. This is to prevent loops or long chaining where a receptor makes a receptor makes a ...