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.
Receptor proteins are designed so special molecules can bind to them, and send messages to the cell that trigger some sort of reaction within the cell. They are embedded in ei â¦ ther the plasma membrane or cytoplasm of a cell, to which a mobile signaling (or signal) molecule may attach.