Question

1. The process of desensitizing a cell to the presence of a signal is called ____________________. State one mechanism by which this is accomplished.

2. What are second messengers and what is their role in cell signaling?

Answer 1

Question 1

The process by which a cell is desensitized to the presence of a signal is called as desensitization.

Mechanism:

Receptor phosphorylatation and uncoupling is one of the most common method for desensitization. it gives rapid results within fraction of seconds.Along with receptor phosphorylation, endocytosis is also used for desensitizating a cell to the signal.

Question 2

Secondary messengers are the intracellular signalling molecules that are released in response to the extracellular signalling molecules.

The secondary messengers are cyclic AMP, cyclic GMP, inositol triphosphate calcium and diacylglycerol.

Function

• They amplify the strenght of existing signal by the primary messenger like harmones and peptides.
• They affect the activation of wide variety of intracellular, enzymes, transporter and ion channels.