NOTES FOR BIOLOGY 1201

Section 001

Spring 2005

DR. STEVEN POMARICO

Cell communication is use to coordinate the activity of individual organisms or the actions of cells within a multicellular organism.

The simplest form of the communication involves chemical interactions.

The communicating cells may be close to each other or far apart.

In many cases the communicating cells may be in direct contact with each other.

Human Regulation: Endocrine Control and Signal-Transduction Pathways - 12.10.1

Communication often triggers a response by the cell receiving the message.

The communication involves three stages:

                     - Signal reception

                     - Signal transduction

                     - Cellular response

In signal reception, a chemical message (ligand) binds to a cellular receptor (usually a protein) and triggers a shape change.

One cellular receptor is a G-protein-linked receptor.

The signal transduction process may include a cascade of events which can amplify the signal.

Signal transduction may involve cyclic AMP (c-AMP).

c-AMP can act as a second messenger in the signal transduction process.

The cellular response can involve:

                     - Turning on (or off) enzymes.

                     - Opening channels to release (or take up) substances.

                     - Activating (or deactivating) the transcription of genes.