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This 2 page Class Notes was uploaded by Kristina Cowan on Tuesday November 3, 2015. The Class Notes belongs to BIOL1081 at The University of Cincinnati taught by Heather Wilkins in Fall 2015. Since its upload, it has received 11 views. For similar materials see Biology 1 in Science at The University of Cincinnati.
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Date Created: 11/03/15
Bio Exam 2 Notes Cellular Signaling Cell to cell communication Coordination of activities Communication between unicellular organisms Locals signaling Direct contact gap junctions animal cells plasmodesmata plant cells Paracrine signaling neighboring cell in same tissue or organ secreted messenger of molecules travel short distance and diffuse out stimulates oca cells and leaves by exocytosis Synaptic signaling electrical signal neurons in brain reaction between neurons and neurotransmitters action potential transmitted along nerve cells neurotransmitter diffuses across synapse Longdistance signaling Endocrine signaling hormones travel via circulatory system target cell can be distant from original source of hormone exocytosis to blood cell then can travel in the bloodstream interacts with target tissues Three Stages of how Interactions Occur Reception signaling molecule goes to receptor a b c d Signal moecue ligand binds to specific receptor Receptor changes shape like a switch Activates receptor Most are plasma membrane proteins integral proteins i Gprotein coupled receptors ii Ligand gated ion channels Gprotein coupled receptors binds to GTP activates G protein ex binds to caffeine Ligand gated ion channel binds to receptor changes shape opens gate and creates a pore for ions to through receptor leaves and gate closes Intracellular receptors inside of the cell in cytoplasm or nucleus of target cells small or hydrophobic chemical messengers cross membrane 2 Transduction signal gets passed a b c Signal cascade Multiple steps can amplify signal Receptor activates protein which activates another and so on until protein producing the response is activated Protein phosphorylation and dephosphorylation i Regulates protein activity ii Protein kinases enzyme transfers phosphates from ATP to proteins phosphorylation changes protein shape often inactive to active iii Protein phosphatase enzyme removes phosphates form proteins desphosphorylation changes protein shape often active to inactive Second messengers other molecules i Signal moecue ligand binds to receptor first messenger ii Second messengers usually ions are small molecules and ions that spread throughout cell by diffusion ex cyclic AMP and calcium ions 3 Response ultimate result activation Regulation of transcription or cytoplasmic activities b In cytoplasm or nucleus c Regulation of transcription turn genes on or off d Regulation of cytoplasmic activity changes in enzyme activity or cell metabolism 0