1. Lucky Ch. 13 Signaling at the Cell Surface
By Lance Ingram

2. Cell Communication
Eukaryotic microorganisms use pheromones for cell-cell signaling to initiate sexual mating
Plants and animals use signal molecules to control metabolic processes, growth and differentiation of tissues, synthesis and secretion of proteins, and the composition of intracellular and extracellular fluids

3. Cell Communication Cont.
Signaling cells release the signal molecules to target cells that have receptors
The signaling molecule is called a ligand that binds to the receptor
Once the signal binds to the receptor it will cause a specific cellular response called a signal transduction

4. Steps in extracellular signalling
Synthesis
Release of signaling molecule by the signaling cell
Transport of the signal to the target cell
Binding of to the signal by a specific receptor protein leading to its activation
Initiation of one or more intacellular signal transduction pathways by the activated receptor

5. Steps Cont.
6. Specific changes in cellular function, metabolism, or development
7. Removal of the signal which often terminates the cellular response

6. Signaling types
Endocrine signaling uses hormones as signaling molecules that act on target cells distant from their synthesis site
Paracrine use signaling molecules that act on target cells in close proximity
Autocrine use signals that the cells themselves release that cause growth and proliferation

7. Thank you Any Questions?
The End
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