1. Cell Signaling
How cells communicate

2. Learning Objectives How do cells communicate long and short distances?
What are the 3 stages of cell signaling?
What is involved in each of the 3 stages of cell signaling?

3. Cell Communication Video

4. Signaling Direct Contact Paracrine Synaptic Local Regulators
Cell junctions
Cell-cell recognition
Paracrine
Growth factors cause cells to grow and multiply
Synaptic
Nervous system
Electrical signal triggers chemical signal – neurotransmitters

5. Signaling Hormones Long-Distance “endocrine signaling”
Cells release hormone molecules into blood vessels where they travel to other parts of the body
Plant hormones can travel through cells, or through air as a gas
Vary a lot in size & type: ethylene vs. insulin

6. Three Stages of Cell Signaling
1. Reception
A chemical signal is “detected” when it binds to a receptor protein on the cell’s surface or inside the cell.
Three Stages of Cell Signaling
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7. Three Stages of Cell Signaling
2. Transduction
The receptor protein changes in response to the signal and initiates the process of converting the signal to a form that can bring about the response.
Can be a single step or a sequence of changes in multiple molecules (“signal transduction pathway”)
Three Stages of Cell Signaling
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8. Three Stages of Cell Signaling
3. Response
Any cellular activity
Must happen in the right cells, at the right time, and in coordination with other cells of the organism
Three Stages of Cell Signaling
A Preview…

9. Signal Transduction Video