bio final

bio final - BIOLOGY FINAL EXAM MATERIAL ON MOODLE -IN THE...

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BIOLOGY FINAL EXAM MATERIAL ON MOODLE -IN THE CELL SIGNALING FOLDER -TWO ITEMS COMMUNICATION AND COORDINATION-cell signaling Cell Communication -Coordinate metabolic processes -Receive “messengers” from both local and distant sources -The messenger is a chemical signal -Respond to the signal through a change in the metabolic processes of the cell -Ex. synthesis of proteins An extracellular chemical signal -Is transduced into an intracellular response -Communication occurs across the plasma membrane -Extracellular signal is amplified within the cell via a signaling cascade Local signaling -Paracrine -Diffusion of “first messengers” over short distance between cells -Synaptic -Chemical signals form a nerve axon diffuse across a synapse to another nerve cell or a muscle cell Long-distance signaling -Hormonal signaling -Endocrine (ductless) glands produce chemicals (hormones) -Hormones move through the circulatory system to their targets Cell Signaling -An extracellular chemicals messenger (hormone) -The extracellular first messenger is transduced (transformed) into an intracellular chemical messenger -Second messenger -Elicits a metabolic change within the cell -May involve a receptor in the plasma membrane -An integral membrane protein -May involve an intracellular receptor -Ex-steroid hormone G poretin0coupled signaling -Important class of signaling complexes -More than 1,000 different receptors in mammals -Coupling= receptors interact with G proteins Alfred G. Gilman and Martin Rodbell -For the discovery of the G proteins and won the Nobel prize in 1994 Guanine-nucleotide-binding proteins (G proteins) -Link an extracellular signal and intracellular response
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BIOLOGY FINAL EXAM MATERIAL Three components -Receptor in the plasma membrane -g protein on the intracellular face is the plasma membrane -“Effector” elements such as enzyme or ion channel Membrane receptors -Over 1,000 G protein coupled receptors (GPCRs) -Integral membrane protein with 7 alpha helical regions spanning the membrane (heptahelical) -Amino terminus extracellular -Carboxy terminus intracellular Heterotrimeric G protein -3 subunits labeled alpha, beta and gamma -Interacts with receptor occupied by a signaling molecule -When activated interacts with an effector element -Associated with the intracellular face of the plasma membrane Effector enzyme (ex adenylyl cyclase) -produces an intracellular “second” Another example of effector element -Ion channel -Controls movement of ions across the plasma membrane G protein –coupled signal transduction system components -Membrane receptor-G protein- adenylyl cyclase GPCR -Activated by binding of a “first” messenger signal molecule -Hormone -Neurotransmitter -Interacts with a G protein Examples of G proteins -Gs-Stimulatory G protein -Stimulates adenylyl cyclase -Gi –inhibitory G protein -Inhibits adenylyl cyclase Other example -Golf-olfactory G protein -Gt- tranducin, the g protein involved in vision G proteins -“Switch” protein -Either “on” or “off” -Activated by occupied (activated) receptor\
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This note was uploaded on 11/03/2011 for the course BIO 1201 taught by Professor Sibenaller during the Fall '10 term at LSU.

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bio final - BIOLOGY FINAL EXAM MATERIAL ON MOODLE -IN THE...

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