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19 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Endomembrane Components
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Er, Golgi, Transport Vesicles, Endosomes, Lysosomes, Vacuoles
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Eight great t.v.'s entertain lovely vacations.
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Three Possible Mechanisms of Protein Transport in the cell?
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1. import into nucleus via nuclear pores
2. import into organelle via protein translocator (mitochondria, chloroplasts, peroxisomes) 3. transport through compartments of the endomembrane system in vesicles |
np/pt/v
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What regulates passage of materials into and out of the nucleus?
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Signal Sequence which directs protens to the correct location and enables a proten to pass through nuclear pores.
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What materials enter the nucleus?
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nuclear proteins from the cytosol
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What materials leave the nucleus?
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mRNAs, tRNAs, and ribosomal subunits are transported from the nucleus to the cytosol
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What materials both enter and leave the nucleus?
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snRNAs move in both directions
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(1)
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Describe the nuclear pore complex.
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-single hela cell
-imports 560k ribosomal proteins and exports 14k ribosomal subunits per minute -octagonals symmetry (30-50 proteins) |
what kind of symmetry? how many proteins?
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What are nucleoporins?
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the 30-50 proteins that make the octagonal symmetry of a nuclear pore complex.
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in nuclear pore complex
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Where is the nuclear pore complex found?
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penetrates the inner and outer nuclear membranes
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Nuclear Localization Sequence
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-necessary and sufficient for nuclear targetting
-directs proteins to correct locations -stretch of AA (one or two short stretches of positively charged AA --arginine (R), lysine (K), histidine (H)) -enables proten to pass through nuclear pores i.e. w/out sequence, protein remains in cytosol if basic aa is replaced by nonpolar aa, no nuclear localization |
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What is the classic NLS from SV40 T antigen?
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pkkkrkv
basic/positive charge |
basic
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Exportins, Importins?
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export and import into nucleus
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Karyopherin
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family of proteins function as transport receptors
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How do proteins enter the mitochondria and chloroplasts?
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proteins unfold as they enter
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Signal Peptidase
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cleaves signal sequence
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Oligosaccharyltransferase
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addition of carbohydrate residues
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Molecular Chaperones (Bip)
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assist in folding
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Protein Disulfide Isomerase
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formation of disulfide bonds
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Where does protein glycosylation occur?
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In the ER
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