Chapter-11-Cell Communication

Chapter –11
Cell Communication

Cell to cell communication is absolutely essential for multicelluar organisms.

The billions of cells of a human or any other animal or plant must communicate in order to coordinate their activities in a way that enables the organism to develop from a fertilized egg and then survive and reproduce.

Types of Signals a Cell Receives

1.Electromagnetic

2.Mechanical

3.Chemical

One topic of cell conversation is sex.

Fig. 11.1- Shows us how two yeast cells signal each other for mating purposes.

Signal Transduction Pathway-The process by which a signal on a cell’s surface is converted into a specific cellular response.

Communicating cells may be close together or far apart.

(a)Paracrine signaling (growth factors)

(b)Synaptic signaling (nerve cells)

(c)Long distance signaling (hormones)

(d)Direct contact

The Three Stages of Cell Signaling

1.Reception

2.Transduction

3.Response

Figure 11.5

Reception-is the target cell’s detection of a signal coming from the outside

Transduction -The binding of the signal molecule changes the receptor protein in some way, initiating the process of transduction. The transduction stage converts the signal to a form that can bring about a specific cellular response.

Response- the transducing signal finally triggers a specific cellular response.The response may be:

(a)Activation of an enzyme

(b)Rearrangement of the cytoskeleton

(c)Activation of a specific gene in the nucleus