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28 Cards in this Set
- Front
- Back
structural proteins compose what structures? |
cytoskeleton, anchoring proteins, much of extracellular matrix |
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most common structural proteins (5) |
collagen, elastin, keratin, actin, tubulin |
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common motor proteins |
myosin, kinesin, dynein |
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binding protein purpose |
bind specific substrate, either to sequester it in the body or hold its concentration at steady state |
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cell adhesion molecules (CAMs) purpose |
allow cells to bind to other cells or surfaces |
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cadherins |
CAM, calcium-dependent glycoproteins that hold similar cells together |
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integrins |
CAM, two membrane-spanning chains, permit cells to adhere to proteins in the extracellular matrix. some have signaling capabilities |
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selectins |
CAM, allows cells to adhere to carbohydrates on the surfaces of other cells, most commonly used in the immune system |
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antibodies/immunoglobulins/Ig |
used by immune system to target a specific antigen |
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what region of an antibody is responsible for antigen binding, and what other regions are there? |
variable region (other region is constant) |
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structure of an antibody |
two identical heavy chains and two identical light chains form a single antibody held together by disulfide linkages and noncovalent interactions |
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ion channels |
used for regulating ion flow into or out of a cell |
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ungated ion channels |
always open |
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voltage-gated ion channels |
open within a range of membrane potentials |
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ligand-gated ion channels |
open in the presence of specific binding substance, usually hormone or neurotransmitter |
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enzyme-linked receptors |
participate in cell signaling through extracellular ligand binding and initiation of second messenger cascades |
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G protein-coupled receptors |
have membrane-bound protein associated with a trimeric G protein. initiate second messenger systems |
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pathway of G protein-coupled receptor activation |
ligand binding engages G protein GDP is replaced with GTP alpha subunit dissociates from the beta and gamma subunits activated alpha subunit alters activity of adenylate cyclase or phospholipase C GTP is dephosphorylated by GDP alpha subunit rebinds to beta and gamma |
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electrophoresis |
uses gel matrix to observe migration of proteins in response to an electric field |
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Native PAGE |
electrophoresis style, maintains protein's shape, but results are difficult to compare because the mass-to-charge ratio differs for each protein |
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SDS-PAGE |
electrophoresis style, denatures the proteins and masks the native charge so that comparison of size is more accurate, but the functional protein cannot be recaptured from the gel |
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isoelectric focusing |
electrophoresis style, separates proteins by their isoelectric point (pI). protein migrates toward an electrode until it reaches a region of the gel where pH=pI of protein |
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chromatography |
separates protein mixtures on the basis of their affinity for a stationary phase or a mobile phase |
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column chromatography |
uses beads of a polar compound, like silica or alumina (stationary phase), with a nonpolar solvent (mobile phase) |
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ion-exchange chromatography |
uses a charged column and a variably saline eluent |
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size-exclusiong chromatography |
relies on porous beads (larger molecules elute first because they are not trapped in the pores) |
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affinity chromatography |
uses a bound receptor or ligand and an eluent with free ligand or a receptor for the protein of interest |
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Edman degradation |
used for amino acid sequencing |