Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
54 Cards in this Set
- Front
- Back
--- Cholesterol ---
Is an organic chemical substance classified as a waxy steroid of ***. |
fat
|
|
Cholesterol...
derived from greek.... |
chole- (bile)
stereos (solid) chemical suffix -ol for an alcohol |
|
--- Cholesterol ---
1) Dampens influence of *** variations on cell membrane permeability / fluidity. 2) In high t, cholesterol acts to *** fluidity. 3) In low t, cholesterol acts to *** fluidity. |
1) temperature
2) decrease 3) increase |
|
--- Cholesterol ---
Important component for the manufacture of *** acids, *** hormones, and vitamin ***. |
bile --- steroid --- D
|
|
--- Cholesterol ---
Cholesterol is the principal *** synthesized predominantly in the *** by animals . |
sterol --- liver
|
|
--- Cholesterol ---
1) Belongs to a family of molecules called *** 2) which are all synthesized from the compound ***. 3) Family includes steroids, bile acids, g***, c*** and u***. |
1) terpenes
2) isoprene 3) gibberellins --- carotenoids --- ubiquinone ubiquinone AKA CoQ10 |
|
--- Cholesterol Biosynthesis ---
1) Pathway consists of ### stages and is 2) located in the *** of liver cells where 3) it begins with the starting compound ***. |
1) 4
2) cytosol 3) acetyl-CoA |
|
--- Stages of Cholesterol Biosynthesis ---
1) Condensation of ### acetate units forming ***... which is 2) converted into molecule *** (#-C)... which undergoes self 3) polymerization into molecule *** (#-C)... which undergoes 4) cyclization forming the steroid nucleus. |
1) 4 --- mevalonate
2) isoprene --- 5C 3) squalene --- 30C 4) |
|
--- Action Words of Cholesterol Biosynthesis ---
1) *** 2) *** 3) *** 4) *** |
1) Condensation
2) Conversion 3) Polymerization 4) Cyclization |
|
--- HMG-CoA Reductase ---
1) Is used in Step ### of *** synthesis and 2) exists as an *** membrane protein of the ***(organelle) 3) where it serves as a *** *** *** and synthesizes mevalonate. |
1) 1 --- Cholesterol
2) integral --- ER 3) key regulatory enzyme |
|
--- Cholesterol Biosynthesis ---
*** is the key regulatory enzyme. |
HMG-CoA Reductase
|
|
--- Cholesterol/Lipid Transport ---
1) C/L from food is packaged as.... 2) C/L from the liver is packaged as... 3) Reverse C/L transport is packaged as... |
1) Chylomicrons
2) VLDL 3) HDL |
|
--- Cholesterol Biosynthesis ---
1) Acetate is shuttled out of the *** (organelle) into the *** 2) as *** in a shuttle system also used during *** *** synthesis. |
1) mitochondria --- cytosol
2) Citrate --- Fatty Acid Synthesis |
|
--- Cholesterol/Lipids ---
1) ***(modification) of Cholesterol increases lipophilicity. 2) Both C&L are transported in the blood as ***. |
1) Esterification
2) Lipoproteins |
|
--- Lipoprotein Compositions ---
1) *** are the least dense. 2) *** are highest in Protein. |
1) Chylomicrons
2) HDL |
|
--- Lipoprotein Compositions ---
1) *** are highest in Cholesteryl Esters. 2) *** are highest in Free Cholesterol. |
1) LDL
2) VLDL & LDL |
|
--- Lipoprotein Compositions ---
1) The *** converts cholesterol into bile salts.... 2) it does NOT uptake cholesterol packaged as... |
1) liver
2) HDL |
|
--- Cholesterol Delivery ---
1) Xport from liver to extrahepatic tissue as... 2) Excess extrahepatic cholesterol is transported back as... 3) 4) |
1) LDL
2) HDL 3) 4) |
|
--- Cholesterol Delivery ---
The liver takes up the *** of LDL, VLDL, and chylomicron by ***. |
remnants
endocytosis |
|
--- Lipoprotein Compositions ---
1) Good cholesterol is AKA... 2) Bad cholesterol is AKA... |
1) HDL
2) LDL |
|
--- Apolipoprotein Location ---
1) ApoA-I??? 2) ApoB-100?? 3) ApoC-II??? 4) ApoE??? |
1) HDL
2) LDL 3) Chylomicrons, VLDL and HDL 4) Chylomicrons, VLDL and HDL |
|
--- Apolipoprotein Location ---
Apo*** is found in HDL |
ApoA-I
|
|
--- Apolipoprotein Location ---
Apo*** is found in LDL |
ApoB-100
|
|
--- Apolipoprotein Location ---
Apo*** is found in Chylomicrons, VLDL and HDL |
ApoC-II
ApoE |
|
--- Cholesterol ---
1) Greatest Consumer of Cholesterol... 2) # distinct mechanisms control Cellular Supply of Cholesterol. |
1) synthesis of bile acid
2) 3 |
|
--- Cholesterol in Normal Adults ---
1) Synthesize # ***/day 2) Consume # ***/day 3) De *** synthesis maintains constant cholesterol level 4) in the body of # - # weight/volume. |
1) 1 g/day
2) 0.3 g/day 3) novo 4) 150 - 200 mg/dL |
|
--- Regulation: Cholesterol Metabolism ---
1) Regulation of *** activity / level. 2) Regulation of excess intracellular free cholesterol by ***. 3) Regulation of *** cholesterol levels via... LDL receptor-mediated *** and HDL-mediated *** ***. |
1) HMGR (HMG CoA Reductase)
2) ACAT (acyl-CoA:cholesterol acyltransferase) 3) plasma uptake --- reverse transport |
|
--- Regulation: HMG CoA Reductase ---
1) Main function is to... 2) Most active form is... 3) P'tion occurs through the enzyme *** when 4) the levels of *** decrease/increase. |
1) synthesize cholesterol
2) deP'ed 3) AMPK (AMP-activated protein kinase) 4) AMP --- increase |
|
--- Regulation: AMPK Activity ---
1) Main function of enzyme is to... 2) It activates *** functions... 3) and deactivates *** functions... |
1) P(inhibit) HMGR (HMG CoA Reductase)
2) catabolism - (glucose Xport, glycolysis, fatty acid oxidation) 3) anabolism (fatty acid, cholesterol, protein biosynthesis) |
|
--- HMG-CoA Reductase ---
1_ Rate controlling enzyme of the *** pathway 2) which controls synthesis of ***. |
1) Mevalonate Pathway
2) cholesterol |
|
--- Mevalonate Pathway ---
1) Rate-controlling enzyme is... 2) Pathway produces cholesterol and other ***. |
1) HMGCR (HMG-CoA Reductase)
2) isoprenoids |
|
--- ATP VS AMP ---
1) *** is a better indicator of a cell’s energetic state. 2) *** is normally found at higher concentrations. |
1) AMP
2) ATP |
|
--- ATP VS AMP ---
1) Typical ATP concentrations are... 2) Typical AMP concentrations are... |
1) 5-10 mM
2) 0.1 mM or less |
|
--- ATP VS AMP ---
If ATP drops by 10% then AMP drops by ***%. |
600%
|
|
muscular contraction
1) ATP + H2O > ??? adenylate kinase 2) ADP + ADP > ??? |
1) ADP + Pi
2) AMP + ATP |
|
adenylate kinase
??? > ??? |
ADP + ADP
>>> AMP + ATP |
|
--- Regulation: Other Hormones & Cholesterol Metabolism ---
1) Glucagon and Epinephrine reduce HMGR activity via ***... 2) Insulin increases HMGR activity via ***.... |
1) PKA and PPI-1 (deP'ed HMGR = less C)
2) PKB (P'ed HMGR = more C) |
|
--- Regulation: Other Hormones & Cholesterol Metabolism ---
1) Hormones *** reduces C synthesis. 2) Hormones *** increases C synthesis. |
1) Glucagon and Epinephrine
2) Insulin |
|
SCAP?
|
SREBP Cleavage Activating Protein
|
|
SREBP?
|
Sterol Regulation Element-Binding Protein
|
|
--- Regulation: Gene Expression & Cholesterol Biosynthesis ---
1) Transcriptional Regulation controls gene expression of *** via a 2) family of proteins called *** which activate transcription upon binding DNA. |
1) HMG-CoA reductase.
2) SREBPs (Sterol Regulation Element-Binding Proteins) |
|
--- SREBP Activation ---
1) SREBP are transcriptional activators of *** and are initially found 2) bound with *** in the membrane of the *** causing it to be inactive. 3) When *** levels decrease, the complex migrates to the *** where its N-terminal domain is cleaved 2x and migrates to the nucleus where it activates transcription of sterol-regulated genes. |
1) HMGR (HMG-CoA Reductase)
2) ER membrane --- SCAP 3) sterol --- Golgi SREBPs (Sterol Regulation Element-Binding Proteins) SCAP (SREBP cleavage activating protein). |
|
--- Mevalonate Synthesis Pathway ---
High flux through this pathways causes high/low rate of HMGR degradation. |
high
|
|
--- Mevalonate Synthesis Pathway ---
1) HMGR is localized to the *** and 2) like SREBP contains a *** domain. 3) *** concentrations of sterol increase HMGR degradation 4) which occurs within a multiprotein complex called the ***. |
1) ER
2) SSD (Sterol-Sensing Domain) 3) Increasing 4) proteosome |
|
The primary signal directing proteins to the proteosome is a # kDa protein called ***.
|
7.6 kDa
ubiquitination |
|
--- Regulation: ACAT & Cholesterol ---
High C concentrations activate ACAT which increases *** of cholesterol for . |
esterfication --- storage
ACAT (Acyl-CoA-Cholesterol AcetylTransferase) |
|
--- Regulation: LDL Receptor & Cholesterol ---
High C levels diminish transcription of LDL receptor genes leading to... 1) +/- number of LDL Receptors and 2) decreased transport of cholesterol from the *** to the ***. |
1) -
2) blood --- cytosol |
|
--- Physiological Functions of Bile Acid ---
1) Only significant mechanism for... 2) Prevents precipitation of *** in the ***. 3) *** agent for triacylglycerols\fat digestion via *** from the ***. 4) Facilitates absorption of... |
1) cholesterol elimination
2) cholesterol --- gallbladder 3) Emulsifying --- lipases --- pancreas 4) fat-soluble vitamins |
|
--- Lipases ---
1) Enzyme that catalyzing the formation or cleavage of *** molecules. 2) They are a subclass of *** enzymes. |
1) fats
2) esterases |
|
--- Conjugated Bile Salts ---
Amide bonds with *** or *** |
glycine or taurine
|
|
--- Statin Drugs ---
1) Act through *** inhibition of the enzyme *** which 2) reduces intracellular cholesterol levels causing the *** 3) to upregulate expression of *** leading to the increased 4) clearance of *** from the bloodstream. |
1) competitive --- HMGR (HMG-CoA reductase)
2) liver 3) LDL receptor 4) LDL (low-density lipoprotein) |
|
Bile Acids OR Salts???
1) Best emulsifying agent? 2) pKa of 4-5 3) OH groups on same side |
1) Salt
2) Salt 3) Acids |
|
--- Bile Salts & Acids ---
Conjugated Bile Salts 1) "Good/Better" emulsifying agents 2) pKa is "higher/lower" 3) Chemically unique in that... |
1) Better
2) lower --- 4-5 pKa 3) Amide bonds with glycine or taurine |
|
--- Bile Acids & Salts ---
Primary Bile Acids 1) "Good/Better" emulsifying agents 2) pKa is "higher/lower" 3) Chemically unique in that... |
1) Good
2) higher --- 5-6 pKa 3) all OH groups are on same side |