Outline Chapter 11

Outline Chapter 11 - Chapter 11 Cell Communication I....

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Chapter 11 – Cell Communication I. External signals are converted to responses within the cell a. Evolution of Cell Signaling i. Yeast sex – a and alpha are two sexes. Type a secrete signaling molecule called a factor which binds to alpha cells. Alpha cells secrete alpha cells that binds to receptors on a cells. ii. Two mating factors can cause cells to grow toward each other into mating. iii. Signal on a cell’s surface is converted to a specific cellular response is a series of steps called a signal transduction pathway – extensively studied in both yeast and animal cells. Molecular details of yeast + mammals similar. iv. Signaling mechanisms first evolved in ancient prokaryotes and single-celled eukaryotes and then go to multicellular etc. – bacterial species secrete molecules that can be detected by other bacteria – quorum sensing v. Bacteria can form biofilms – aggregation of bacteria that form recognizable structures containing region of specialized function b. Local and Long-Distance Signaling i. Cell junctions connect cytoplasms of adjacent cells ii. Animal cells can communicate through direct contact iii. Messenger molecules are secreted by the signaling cell – some such as local regulators influence cells in vicinity. One class of local regulators in animals – growth factors – stimulate nearby target cells to grow and divide. Numerous cells can simultaneously receive and respond to molecules of growth factor produced by single cell in vicinity. Type of local signaling is called paracrine signaling. iv. Synaptic signaling – electrical signal along nerve cell triggers the secretion of a chemical signal carried by neurotransmitter molecules. Diffuse across synapse – neurotransmitter stimulates target cell v. Both animals and plants use hormones vi. Animals – endocrine signaling – specialized cells release hormone molecules, which travel via circulatory system to target cells in other parts of the body. vii. Plant growth regulators – travel in vessels but more often reach their targets by moving throughcells or by diffusing through the air as a gas. viii. Vary in molecular size and type. ix. Transmission of signal through nervous system could be long- distance signaling. Electrical signal travels length of nerve cell and then converted back to chemical signal when signaling molecule is released and crosses the synapse to another nerve cell. x. Molecule recognized by specific receptor molecule and info, signal transduced inside cell before it can respond.
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II. The Three Stages of Cell Signaling: A Preview a. Epinephrine stimulates breakdown of glycogen within liver cells and skeletal muscle cells. b. Glyocgen breakdown releases glucose-1-phosphate which converts to glucose-6-phosphate. c.
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This note was uploaded on 02/14/2011 for the course BISC 220L taught by Professor Herrera,mcclure during the Spring '07 term at USC.

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Outline Chapter 11 - Chapter 11 Cell Communication I....

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