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34 Cards in this Set
- Front
- Back
receptor proteins
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-have a 3-dimensional shape that fits a specific signal molecule.
-when a signal molecule and a receptor protein bind, a change in the receptor protein is induced and a response is generated. |
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techniques for finding receptor proteins
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1) immunochemistry
2) molecular genetics |
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types of cell signaling
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1) direct contact
2) paracrine signaling 3) endocrine signaling 4) synaptic signaling -autocrine signaling |
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autocrine signaling
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when cells send signals to themselves, secreting signals that bind to specific receptors on their own plasma membranes.
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direct contact
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cell to cell is in close contact
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paracrine signaling
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signal molecules are released by a cell that diffuse through the extracellular fluid to other cells, but it short lived and localized.
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endocrine signaling
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signal molecules released by cells remain in extracellular fluid for a long time and travel wideley throughout body.
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hormones
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longer lived signal molecules used in endocrine signaling
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synaptic signaling
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intracellular communication that provides rapid communication using neurtransmitters, which move through a synaptic gap rather than through intracellular fluid.
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neurotransmitters
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signal molecules used in synaptic signaling
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chemical synapse
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association of a neuron and its target cell
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intracellular receptors
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receptors located within the cell and trigger a variety of activity
- ex: act as gene regulators act as enzymes |
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cell surface receptors
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receptor proteins on the outer surface of the cell that convert the extracellular signal to an intracellular one.
-useful for water soluble signals that cannot diffuse through plasma membranes. |
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Types of cell surface receptors
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1) Chemically Gated Ion Channels
2) Enzymic Receptors 3) G Protein Linked Receptors |
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chemically gated ion channels
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open or close when signal molecules bind to the channel
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enzyme receptors
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usually activate intracellular proteins by phosphorylation
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ion channel
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pore in chemically gated ions channels which ions pass through
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protein kinases
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enzyme activated when a signal molecule binds to an enzyme receptor, it adds prosphate groups to proteins
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G protein linked receptors
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acts indirectly on enzymes or ion channels in the plasma membranes with the aid of an assisting protein, G protein (aka GTP)
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G protein
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assisting protein in G protein linked receptors
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second messengers
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relay messages from receptors to target proteins.
ex: cAMP (found in all animal cells) calcium ions (high outside cell and in ER, low in cytoplasm. |
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adenylyl cyclase
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stimulated by G protein, produces large amounts of cAMP within the cell
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tissues
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highly specialized groups of cells (blood, muscle)
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cell identity
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cells contain an array of marker proteins located on the cell surface
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tissue specific identity markers
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glycolipids (tissue specific cell surface markers)
MHC proteins (self from nonself) |
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cell junctions
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long lasting or permanent connections inbetween cells
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types of cell junctions:
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tight junctions
anchoring junctions communication junctions |
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tight junctions
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connect plasma membranes of adjacent cells in a sheet, preventing small molecules from leaking inbetween the cells
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anchoring junctions
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mechanically attach the cytoskeleton of a cell to the cytoskeletons of other cells or the extracellular matrix
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desmosomes
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anchoring junctions that connect the cytoskeletons of adjacent cells using cadherins (critical link)
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adherens junctions
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anchoring junctions that connect the actin filaments of one cell with those of neighboring cells or with extracellular matrix (critical link in this is integrin)
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communicating junctions
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chemical or electrical signal passes directly from one cell to an adjacent cell
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gap junctions
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communicating junctions in animal cells
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plasmodesmata
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communicating junctions in plant cells
-contain central tubule that connects the ER of the two cells |