- How are cells of yeast identify their mates?
Cells of yeast identify their mates by chemical signaling.
- What is signal transduction pathway?
The process of which a signal on a cell's surface is converted to a specific cellular response.
- What are the two mating types?
Mating type a and mating type α.
5 Main Facts:
- Numerous cells can simultaneously receive and respond to the molecules of growth factor produced by a single cell in their vicinity.
- Both animals and plants use chemicals called hormones for long distance signaling.
- Epinephrine stimulates glycogen phosphorylase.
- There are three stages of cell signaling: reception, transduction, response.
- Ligand binding is similar to the binding of an allosteric regulator to an
enzyme, causing a shape change that either promotes or inhibits enzyme activity.
Diagram
The receptor protein is activated, it is detected by specific relay proteins inside the cell. Each protein binds to a specific phosphorylated tyrosine, undergoing a resulting structural change that activates the bound protein. Each activated protein triggers a transduction pathway, leading to cellular response.
Summary
Cell to cell communication is essential for multicellular organism. Trillions of cells in a multicellular organisms must communicate with each other to coordinate their activities in a way that enables the organism to develop from a fertilized egg, then survive and reproduce in turn.
There are three stages of cell signaling: reception, transduction, response. Reception is the detection of target cell of a signaling molecule coming from outside of the cell. Transduction is the binding of the signaling molecule changes the receptor protein in some way, initiating the process of transduction.
Video:
10 Key Terms:
- Local regulator: a secreted molecule that influences cells near where it is secreted.
- Hormones: in multicellular organisms, one of many types of secreted chemicals that are formed in specialized cells, travel in body fluids , and act on specific target cells in other parts of the body to change their functioning.
- Ligand: a molecule that binds specifically to another molecule, usually a larger one.
- G protein: a GTP-binding protein that relays signals from a plasma membrane signal receptor to other signal transduction proteins inside the cell.
- G protein coupled receptor: a signal receptor protein in the plasma membrane that responses to the binding of a signaling molecule by activating a G protein.
- Receptor tyrosine kinase: a receptor protein in the plasma membrane, the cytoplasmic part of which can catalyze the transfer of a phosphate group from ATP to a tyrosine on another protein.
- Ligand-gated ion channel: a protein pore in cellular membranes that opens or closes in respones to a signaling chemical, allowing or blocking the flow of specific ions.
- Protein kinase: an enzyme that transfers phosphate groups from ATP to a protein, thus phosphorylating the protein.
- Protein phosphatase: an enzyme that removes phosphate groups from proteins, often functioning to reverse the effect of a protein kinase.
- Second messenger: a small, nonprotein, water soluble or ion, such as a calcium ion or cyclic AMP, that relays a signal to a cell's interior in response to a signaling molecule bound by a signal receptor protein.
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