Term
| Free form of cholesterol description |
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Definition
Hydroxyl (-OH) group on carbon 3
-Synthesized and absorbed in free form |
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Term
| Synthesis of cholesterol occurs in... |
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Definition
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Term
| Dietary cholesterol in____cells are esterified and packaged into____ for transport to the ___ |
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Definition
| Dietary cholesterol in MUCOSAL cells are esterified and packaged into CHYLOMICRONS for transport to the LIVER |
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Term
| (1) Which molecules esterify cholesterol and (2) where are they found |
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Definition
LCAT- plasma
ACAT 1- phagocyte, steroid producing cells
ACAT 2- liver
LCAT= lecithin-cholesterol acyltransferase
ACAT= acyl-CoA:cholesterol acyltransferase |
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Term
| Cholesterol synthesis rate limiting step is... |
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Definition
HMG-CoA--->mevalonate via enzyme HMG-CoA Reductase
Mevalonate formation is the rate limiting step |
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Term
| Mevalonate can form isoprenoids, like: |
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Definition
Cholesterol
Steroid hormones
Ubiquinone- ETC H+ carrier
Dolichol- synth. of ologosaccharides and glycoproteins
Farnesyl- anchor proteins to membranes |
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Term
| Cholesterol used to make... |
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Definition
| Bile salts Cell membranes Vitamin D (Ca2+ absorption) Cortisol, aldosterone Testesterone, estradiol |
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Term
| The most abundant sterol in the plasma membrane is- |
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Definition
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Term
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Definition
| HMG-CoA Reductase Phosphatase |
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Term
| HMG-CoA Reductase Phosphatase causes... |
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Definition
HMG-CoA Reductase--->active
Cholesterol synthesis |
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Term
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Definition
Protein Kynase--->inactive
HMG-CoA Reductase phosphorylated-X->cholesterol |
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Term
| Inhibitors of HMG-CoA Reductase |
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Definition
Glucagon
Glucocorticoids
Statins
High IC [cholesterol] |
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Term
| Activators of HMG-CoA Reductase |
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Definition
Insulin
T3
ATP
Low IC [cholesterol] |
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Term
| High IC [cholesterol] causes... |
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Definition
Inhibition of SREBP (sterol-regulatory element-binding protein)
-->Decreased HMG-CoA Reductase transcription
-->Inhibition of HMG-CoA Reductase activity |
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Term
| Low levels of IC cholesterol causes... |
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Definition
Activation of SREBP (due to lack of inhibitory cholesterol)
SREBP binds to SRE
Transcription, translation of active HMG-CoA Reductase
Increased cholesterol synthesis |
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Term
| Why is polyunsaturated esterification bad? |
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Definition
| PUFA easily oxidized to form oxygen free radicals |
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Term
| Free lipid radicals are bad because |
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Definition
Lipid radicals oxidize other PUFAs in chain-like reaction
Free radicals change permeability of membrane, DNA oxidation too
If cholesterol rich LDL gets oxidized, it begins the formation of atherosclerotic plaque |
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Term
| (1) Name 3 antioxidants and (2) their action |
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Definition
(1) Vitamin C and E (lipid soluble) and selenium
(2) Inactivate free radicals |
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