Receptors - o shape/charge of channel determines what type...

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Receptors intracellular receptors - protein receptors within the cell signal molecules are usually lipid-soluble or very small in order to pass through the membrane gene regulating receptors - has binding site for DNA o inhibitor protein may prevent DNA from binding o either activates or suppresses certain genes after binding to DNA o response varies depending on the cell o lipid-soluble signal molecules tend to last longer than water-soluble signals regulators as enzymes - catalyzes reactions when activated o nitric oxide binds to guanylyl cyclase, catalyzes synthesis of GMP (messenger molecule that relaxes smooth muscle cells) cell surface receptors - accounts for the majority of a cell's receptors turns extracellular signals into intracellular ones water-soluble signals can't pass through the membrane, must bind w/ surface receptors chemically gated ion channels - allow ions through o opens only when a neurotransmitter binds to it
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Unformatted text preview: o shape/charge of channel determines what type of ion goes through it • enzymic receptors- activates an enzyme when binding to a signal molecule o protein kinases- enzymes that add phosphate groups to proteins o binds to signal molecule outside the school, enzyme activity occurs in the cytoplasm G-protein linked receptors- uses GTP-binding protein to indirectly act on enzymes/ion channels • starts a diffusible signal within the cell • has short duration • G-protein changes shape, leaves receptor once signal molecule arrives • GTP can start few events, turns into GDP+phosphate very quickly • pathway shuts down if signals stop coming in • threads back and forth across the membrane 7 times (7-pass transmembrane protein) • more of these surface receptors than any other kind • may have evolved from sensory receptors of prokaryotes • Rodbell/Gilman - received Noble prize for work w/ G-proteins...
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This note was uploaded on 01/04/2012 for the course BSC BSC1005 taught by Professor Orlando,rebecca during the Fall '10 term at Broward College.

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