BILD 1 Chapter Eleven

BILD 1 Chapter - Chapter Eleven-Cell Communication 11.1 External Signals are Converted into responses within the Cell Evolution of Cell Signaling

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Chapter Eleven-Cell Communication 11.1 External Signals are Converted into responses within the Cell Evolution of Cell Signaling Saccharomyces cerevisiae: (normally in yeast cells) o Cells of mating type a secrete a chemical signal called a factor which bind to specific receptor proteins on nearby alpha cells. At the same time, alpha cells secrete alpha factor to bind to receptors on a cells. The two mating factors cause the cells to grow toward each other and bring about their cellular changes. This causes fusion of two cells of opposite type. The new a/alpha cell contains both the original genes Signal transduction pathway- process and series of steps by which a signal on a cell’s surface is converted into a specific cellular response Local and Long-Distance Signaling Cells in multicellular organism usually communicate via chemical messengers targeted for cells that may or may not be immediately adjacent Cell junctions-allow molecules to pass readily between adjacent cells without crossing plama membranes Cell-cell recognition- two animal cells communicate by interaction between molecules protruding from their surfaces Local regulators- signals which travel short distances o Paracrine signaling- compounds hat stimulate nearby target cells to grow and multiply o Synaptic signaling- in the nervous system an electrical signal along a nerve cell triggers the secretion of a chemical signal in the form of neurotransmitter molecules which diffuse across synapse to stimulate the target cell Long Distance o Hormones- chemicals used in both plants and animals for long-distance signaling o In animals hormonal signaling (endocrine signaling) releases hormone molecules into vessels of the circulatory system, by which they travel to target cells in other parts of the body o In plants hormonal singaling (growth regulators) sometimes travel through vessels but mainly travel through cells or by diffusion through the air as a gas. Three Stages of Cell Signaling 1) Reception- target cell’s detection of a signal molecule coming from outside the cell. A chemical signal is “detected” when it binds to the receptor protein located at the cell’s surface
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This note was uploaded on 04/09/2008 for the course BILD 1 taught by Professor Boulanger during the Fall '08 term at UCSD.

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BILD 1 Chapter - Chapter Eleven-Cell Communication 11.1 External Signals are Converted into responses within the Cell Evolution of Cell Signaling

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