Lecture 27 - Molecular and Cell Biology Cheryl Davis, instructor. Specific sequence necessary for retention in Golgi.
All cells receive and respond to signals from their surroundings.
The signals may be environmental factors like light or they may be signals produced by other cells . Signals from other cells are especially important in complex multicellular organisms, like humans, where they integrate and coordinate the functions of the individual cells for the benefit of the whole organism. Such signaling molecules are called hormones , per definition signal molecules that act over great distances. But a cell will only respond to a signal, if it is able to perceive the signal. This is accomplished via receptors which are proteins that specifically bind signal molecules.