Biology Chapter 11

Biology Chapter 11 - Chapter 11: Cell Communication...

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Chapter 11: Cell Communication Evolution of Signaling - Researchers learned that yeast cells identify their mates by chemical signaling - There are two sexes (mating types) - a: secretes a chemical signal called a factor, which can bind to specific receptor proteins on nearby α cells. - α : cells secrete a α factor, which bonds to receptors on a cells. - The two mating cells grow towards each other and bring about other cellular changes - The result is the fusion/mating of two cells of the opposite type - The new a/ α cell contains all the genes of both original cells - Signal transduction pathway: the process by which a signal on a cell’s surface is converted into a specific cellular response Local and Long-Distance Signaling - Cells may communicate directly - Animal and plant cells have cell junctions, which directly connect the cytoplasm of adjacent cells - Signaling substances could pass freely between adjacent cells - Cell-cell recognition: when animal cells communicate by direct contact between membrane bound cell surface molecules - Important in embryonic development and the immune response - Local regulator: a chemical messenger that influences cells in the vicinity - Paracrine Signaling: A secreting cell that acts on nearby target cells by discharging molecules of a local regulator into the extra cellular fluid. (example: growth factor) - Synaptic Signaling: A nerve cell that releases neurotransmitter molecules into a synapse, stimulating the target cell - Hormones: (endocrine signaling) used by both the animal and plant cell for long distance signaling - Hormone Signaling: specialized cells that release hormone molecules into vessels of the circulatory system, by which they travel to target cells in other parts of the body - Plant Hormones: (growth regulators) sometimes travel in vessels, but more often reach their t target by moving through cells or by diffusion through air as gas - Transmission of a signal through the nervous system can be considered a long distance signaling - Electrical signals travel the length of a nerve cell, and is converted back to a chemical signal that crosses the synapse to another nerve cell, then it’s converted back into an electrical signal - They travel along a series of nerve cells (nerve cells are long, the nerve signal travels long distances) The Three Stages of Cell Signaling: A Preview - Reception: Target cell’s detection of a signal molecule coming from outside the cell, chemical signal is detected when it binds to a receptor protein located at the cell’s surface (or inside the cell) - Transduction: Converts the signal to a form that can bring about a specific cellular response - Response: The transduced signal finally triggers a specific cellular response - Examples: catalysis by an enzyme, rearrangement of the cytoskeleton or activation of specific genes in the nucleus - Cell signaling process helps ensure that crucial activities occur in the right cells, at the right time, and in proper coordination with the other cells of the organism
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This note was uploaded on 11/04/2010 for the course BIO 107 taught by Professor Abott during the Fall '09 term at UConn.

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Biology Chapter 11 - Chapter 11: Cell Communication...

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