Term
| Composition of Memebranes (4 main things) |
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Definition
phospholipids
glycolipids
cholesterol
proteins |
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Term
| Properties and Function of Cholesterol |
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Definition
-control/buffer for mem fluidity
-rigidifies in high temp,
-fluidifies in cold... |
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Term
| Extrinsic vs Intrinsic Mem Proteins |
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Definition
extrinsic - peripheral; removed by gentle methods; tend to be receptors or for cell-cell aggregation; electrostatic or hydro-phobic/-philic interactions
intrinsic - integral; strong detergents needed to remove; strong hydrophobic interactions w/ mem |
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Term
T or F
Some proteins are covalently bound to lipids in the membrane |
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Definition
True (e.g. myristic acid attached to N-term Gly of protein; palmitic acid, Phosphostidylinositol...)
- covalently bound lipids attached post-translationally
- probably func as anchor |
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Term
Which are permeable/impermeable to the cell mem?
Gases (CO2, N2, O2)
Small uncharged polar molec (Ethanol)
H2)
Urea
Large uncharged polar molec (Glc)
Ions
Charged polar molec |
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Definition
permeable - gases, small uncharged polar molec, (sometimes water)
All other impermeable |
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Term
| Receptor-mediated endocytosis internalizes what types of substances/molecules? |
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Definition
| tranport proteins (i.e. LDL - cholesterol trans; transferrin - iron transport; transcobalamin - B12 transporter; hormones such as insulin; growth factors, immunoclobulins; lysosomal enzymes) |
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Term
| All rec-med endocytosis receptors are... |
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Definition
| integral mem glycoproteins |
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Term
| What are the 4 fates of a vessicle in rec-mediated endocytosis |
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Definition
1) recycling
2) transcytosis
3) degradation
4) sequestration |
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Term
| What is the transcription factor that controls the abundance of HMGT-CoA Reductase and LDL receptors? |
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Definition
| Sterol-Regulatory-Element Binding Protein (SREBP) |
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Term
| What are the various phenotypic variations of FH (Familial Hypercholesterolemia)? |
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Definition
1) No Receptor Synth - usually deletion in the coding region of gene
2) Incomplete Processing - incomplete post-translational modificaiton, esp carb procressing,. Never reach cell surface.
3) Receptors synth & processed but no binding LDL - mutations affecting seq of binding domain.
4) Rec bind LDL but no pit formation - probably some signal on cytosol side that gathers clathrin (remember - unlike other cases, clathrin gathers around LDL-rec regardless of ligand)
5) Internalization but doesn't release LDL even after acidificaiton of vesicle |
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Term
| Characteristics of Mammilian Fatty Acids |
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Definition
-even numbered
-chain length b/w 12 and 24
-sat or unsat
-if unsat, then all dbl bonds cis
-multiple dble bonds separated by one methylene grp
-unbranched |
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