Term
| Local and Long-Distance Signaling are essential for what type of organisms? |
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Definition
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Term
| Name the three ways in which cells in a multicellular organism communicate. |
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Definition
physical contact (local)
electrical signals (local and long distance)
chemical messengers (local and long distance) |
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Term
| What three processes did Earl W. Sutherland suggest that cells receiving signals went through? |
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Definition
Reception, transduction and response
he also discovered how the hormone epinephrine acts on cells |
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Term
| Signal transduction pathway |
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Definition
| a series of steps by which a signal on a cell's surface is converted into a specific cellular response |
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Term
| Multistep signal transduction pathways can _____ a signal causing a few molecules to produce a large cellular response. |
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Definition
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Term
| What is typically the initial transduction of the signal? |
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Definition
| shape change in a receptor(most of theses signal receptors are plasma membrane proteins) |
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Term
| Many signaling processes occur by protein _____. |
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Definition
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Term
water soluble signal molecules bind to specific sites on receptor proteins in the ___ ____.
hydrophobic signals (ex: steroids) travel through the cell membrane and bind to _____ or _____ receptors. |
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Definition
plasma membrane
cytoplasmic or nuclear |
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Term
| the final activated molecule in a signalling pathway may function as a ___ ____. |
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Definition
transcription factor
(term loosely applied to any protein required to initiate or regulate transcription in eukaryotes. Includes transcription regulators as well as the general transcription factors) |
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Term
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Definition
| protein that binds specifically to a regulatory DNA sequence and is involved in controlling whether a gene is switched on or off |
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Term
| ligand-gated ion channel receptor |
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Definition
acts as a gate when the receptor changes shape
the gate allows specific ions such as Na+ or Ca2+ through a channel in the receptor |
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Term
| Where are G protein-coupled receptors located? |
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Definition
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Term
| G proteins are active when bound to _____, and inactive when bound to ____. |
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Definition
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Term
| What is a first messenger? |
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Definition
| the extracellular molecule that binds to the receptor in a pathway |
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Term
| What is a second messenger? |
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Definition
a small water-soluble molecule (nonprotein or ion) formed in or released into the cytosol by diffusion in response to an extracellular signal that helps to relay the signal to the interior of the cell.
examples inclue IP3, cAMP and Ca2+ |
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Term
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Definition
made by adenylyl cyclase which is an enzyme in the plasma membrane that converts ATP to cAMP in response to an extracellular signal
it acts as a signaling molecule by activating protein kinase A (which then phosphorylates various other proteins) |
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