Cell signalling is used to control processes inside the body when the environment changes this happens by:
1. One cell releasing a messenger molecule for example a hormone.
2. The molecule travels in the blood to another cell.
3. The messenger is detected by another cell when it binds to a receptor on its membrane.
The membrane receptors are specific shapes (complimentary) so only the correct messenger molecule can bind to the correct target cell for example glucagon a hormone released when there isn't enough glucose in the blood and…