They allow molecules to pass readily between adjacent cells without crossing the plasma membrane. This is the exchange of SMALL MOLECULES ONLY.
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What is Cell-cell recognition?
These communicate by interaction between molecules of their surface.
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Describe Paracrine signalling?
Signal molecules are produced by the transmitting cell and then diffuse LOCALLY until they reach the target cell receptor.
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Describe Synaptic signalling?
Occurs at the synapse between two cells. This is more directed.
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Describe Endocrine signalling?
Hormones transported through blood to other side of the body to target cells.
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What is signal transduction?
The way a cel responds or adapts to changes in its environment.
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What is a receptor?
A specific cellular protein on CSM that binds to ligands.
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Describe the process of molecular recognition?
The specificity of signalling spend on the ligand-receptor interaction. This acts as a switch. The signalling molecule binds when the receptor is phosphorylated.
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Describe the reception (1st) phase of cell signalling?
Target cells detect external signal. A ligand is detected when it binds to a receptor at the CSM.
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Describe the Transduction (2nd) phase of cell signalling?
This signal is converted into another signal. The receptor binds to ligands and becomes activated. The receptor alerts effector which sends signal into the cell.
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Describe the Response (3rd) phase of cell signalling?
The transducer signal triggers a specific cellular response and bring about a change in cell activity.
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What is the effect of a transcription factor in cell signalling?
The activation of a TF changes gene expression. The TF may inhibit or intensify the same signalling cascade.
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What occurs when the TF is active?
There is MUCH gene product as signalling cascade has been intensified.
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What occurs when the TF is inactive?
There is not MUCH gene product as the signalling cascade is inhibited.
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How does Amplification work?
This process uses enzymes in which each molecule of enzyme that is activated MANY molecules of product will be produced.
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Other cards in this set
Card 2
Front
How do prokaryotic organisms respond to environmental changes?
Back
They control flagella motion (move towards/away from stimulus) and synthesise new proteins to optimise survival-activation of gene synthesis.
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