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14 Cards in this Set
- Front
- Back
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Proteins moving into where contain a specific targeting sequence?
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Nucleus, mitochondria, peroxisomes or endoplasmic reticulum
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What do integral proteins contain to remain in the ER membrane?
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An ER targeting sequence and one or more "stop transfer sequences"
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What is a "regulated secretion" signal? vs. constitutive secretion?
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Regulated - causes proteins to be packaged in secretory vesicles and held in teh cytoplasm until a secretion signal is received vs. imeddiately sent to cell surface for secretion.
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What signal are lsyosomal enzymes given?
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mannonse-6-phosphate
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What is the difference b/n HSP70 and HSP60?
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HSP 70 - small chaperones tha tbind to hydrophobic regions of unfolded, nascent chains to protect them from proteolysis and held them fold properly using ATP
HSP 60 - very large, barrel-shaped complexes with a sheltered caviety where nascent protein can fol dproperly. Use ATP |
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What are proteasomes?
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Large and barrel-like protease assemblies that degrade protein if they fail to fold properly, become secondarily unfolded or damaged
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What must protein be tagged wtih to be recognized and internalized by proteasomes?
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Ubiquitin
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What are MHC (major-histocompatibility) proteins?
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Attach protein fragments from proteasomes and travel from ER to Golgi to membrane and display fragments. Immune cell sniff at fragments and destroy cell if foreign fragments detected.
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What are SRPs?
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Signal recognition particle - recognizes nascent peptide with ER localization signal (start transfer sequence) brings ribosome, SRP and peptide to ER dock.
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What is the major difference b/n N and O- linked glycosylation?
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O-glycosylation occurs only the Golgi. Also attaches to Serine or threonine, not asparagine like N-glycosylation.
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Where are the M6P-labeled hydrolases recognized?
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In the trans-Golgi by an M6P-receptor
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Besides N and O-linked glycosylation, what addition protein processing occurs in the Golgi?
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1) Attchmnt of sulfate groups to sugars
2) Proteolysis 3) Formation of disulfide bonds and folding of nascent peptides |
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What is Clathrin?
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Coats interior of pits during pinocytosis that facilitates the rounding of the pti into a vesicle that can pinch off from the surface.
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What is autophagocytosis?
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Housekeeping process in which entire regions of cytoplasm adn organelles are enveloped by cisternae of ER and sealed off, then fuse with mature lysosomes and digested.
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