Biochem - Block 3 - Part 1

davidwurbel7's version from 2015-04-19 06:31


Fatty Acid Synthase Complex

Question Answer
The final two carbons in Fatty Acid synthesis come fromAcetyl CoA
The rest of the carbons in Fatty Acid synthesis come fromMalonyl CoA
Added to acetyl CoA by Acetyl CoA Carboxylase to change acetyl CoA to malonyl CoA but does not contribute any carbons to the final Fatty Acid chainCarbon Dioxide
The most common placement of a double bond is between carbons 9 and 10 by ___________Δ9 Desaturase
Humans cannot make fatty acids with double bonds past the _______9th Carbon

Fatty Acid Synthase Complex (FAS Complex)

Question Answer
The first reaction of FAS Complex is a _________ reactionCondensation/Decarboxylation
The second reaction of FAS Complex is a _______ reactionReduction
The third reaction of FAS Complex is a ________ reactionDehydration
The fourth reaction of FAS Complex is a _________ reactionReduction

Fatty Acid Structure

Question Answer
An ω6 fatty acid with a structure of 18:2, Δ9,12Linoleic Acid
An ω3 fatty acid with a structure of 18:3, Δ9,12,15α-Linolenic Acid
Synthesized from α-Linolenic Acid with a structure of 20:4, Δ5, 8,11,14Arachidonic Acid
Precursor of prostaglandins and thromboxanesArachidonic Acid
Precursor of a class of eicosanoidsEicosapentaenoic Acid

Triacylglycerol Synthesis

Question Answer
Activation of fatty acid is catalyzed by _________ which required two high-energy phosphatesAcyl CoA Synthetase (Thiokinase)
Glycerol-3-phosphate is synthesized in liver and adipose tissue by ____________ from dihydroxyacetone phosphate (DHAP) synthesized from glucoseGlycerol Phosphate Dehydrogenase
Only in the liver, glycerol is converted to glycerol-3-phosphate byGlycerol Kinase

Cholesterol and Cholesterol Synthesis

Question Answer
What organ is cholesterol primarily synthesized inLiver
All 27 carbons present in cholesterol are derived from one precursorAcetyl CoA
Acetyl CoA is convert to _________ which is the starting substrate of cholesterol synthesisMevelonate
Catalyzed step is committed and rate determining for cholesterol biosynthesisHMG CoA Reductase
Active when in a dephosphorylated state and regulated by reversible phosphorylationHMG CoA Reductase
Statins drugs inhibitHMG CoA Reductase
Insulin binds to protein phosphatase which dephosphorylates ______ activating itHMG CoA Reductase
Has a negative effect on HMG CoA ReductaseMevelonate
Final end product and bile acid products have a negative effect on HMG CoA ReductaseCholesterol
If high level of cholesterol in the cytoplasm, cholesterol production in inhibited by cholesterol binding toSCAP
With SCAP not bound by cholesterol, this DNA-binding domain moves into the nucleus and induces transcriptionSREBP
The three fates of this molecule is to become cholesterol, CoQ, or dolicholFarnesyl Pyrophosphate (FPP)
Catalyzes the transfer of a fatty acid from coenzyme A to the hydroxyl group on carbon 3 of cholesterol producing a cholesterol esterAcyl CoA-Cholesterol Acyl Transferase (ACAT)
This vitamin is also loaded onto APO-B100 with cholesterol esters during formation of VLDLVitamin E
Can be converted into cholesterol ester, biliary cholesterol, or bile acidsHepatic Cholesterol

Fates of Cholesterol

Question Answer
The rate limiting enzyme of bile salts and bile acids7α-hydroxylase
Cholyl CoA and Chenodeoxycholyl CoA are derived from7α-hydroxycholesterol
Bile acid with a pKa of 2Taurocholic Acid and Taurochenodeoxycholic Acid
Bile acid with a pKa of 4Glycocholic Acid and Glycochenodeoxycholic Acid
Bile acid with a pKa of 6Cholyl-CoA and Chenodeoxycholyl-CoA
There are how many primary bile acids4
There are how many secondary bile acid2
95% of all bile acids and salts are reabsorbed in the Ilium. The major component of the 5% that is lost is composed ofLithocholic Acid
A lipid soluble, mobile complex present in the electron transport chainUbiquinone (Coenzyme Q, CoQ)
Found in higher quantities in organs with the highest energy requirements—such as the heart, neurons, liver and kidneyUbiquinone (Coenzyme Q, CoQ)
A polyprenol, a product of HMG-CoA reductase making mevalonate and subsequently farnesyl pyrophosphateDolichol
Plays a role in the co-translational N-glycosylation of proteoglycans and glycoproteinsDolichol
Converted into progesterone which can be converted into any of the following; cortisol, corticosterone which can then be converted into aldosterone, testosterone which can then be converted into estradiolCholesterol

Lipoprotein Metabolism

Question Answer
Lowest density of lipoproteinChylomicrons
Highest density of lipoproteinLp(a)
Based on electrophoretic mobility, this lipoprotein is called alphaHDL
Based on electrophoretic mobility, this lipoprotein is called betaLDL
The name of the apolipoprotein necessary for formation of chylomicronsApo B-48
Another apolipoprotein component of chylomicronsApo C-II
The major lipoprotein component of chylomicrons and remnant chylomicronsApo B-48
The major lipoprotein component of VLDL, IDL, LDL, Lp(a)Apo B-100
The major lipoprotein component of HDLApo A-I
The secondary lipoprotein component of chylomicrons and VLDLApo C-II
The secondary lipoprotein component of remnant chylomicrons and IDLApo E
The secondary lipoprotein component of Lp(a)Apo(a)
Has no secondary lipoprotein componentLDL
Has all other secondary lipoprotein except for Apo B'sHDL
The other constituents of chylomicrons and remnant chylomicronsVitamins A, D, E, and K
The other constituents of VLDL, IDL and LDLVitamin E
The other constituents includes LCAT, CETP and paroxonaseHDL
Hydrolysis of triacylglycerols are catalyzed by __________, mainly in muscle and adipose tissueEndothelial Lipoprotein Lipase (LPL)
Endothelial Lipoprotein Lipase (LPL) is an extracellular enzyme that is anchored to the capillary endothelium byHeparan Sulfate
Endothelial Lipoprotein Lipase (LPL) is activated by _______ which is present on circulating lipoproteinApo C-II
HDL donates apoproteins C-II and E which are given to nascent chylomicrons to formMature Chylomicrons
Nascent chylomicrons form from mature chylomicrons after HDL donatesApo C-II and E
Chylomicron remnants are taken up by remnant receptors through receptor-mediated endocytosis in the liver which will recognize __________ over the surface of chylomicronsApo E
The liver loads triacylglycerol, phospholipids, ----------- onto __________ to be distributed throughout the bodyApo B-100
Triacylglycerol, phospholipids, _________ loaded onto Apo B-100VLDL
Protein that loads TAGs along with free and esterified cholesterol, phospholipids and vitamin E onto Apo B-100MTP
IDL does not contain _________ donating this protein back to HDLApo C-II
IDL donates _______ to HDL to become LDLApo E
LDL can be reabsorbed by the liver the receptor-mediated endocytosis byApo B-100 receptor (LDL receptor)
Competes with plasminogen for its substrate reducing the effectiveness of fibrinolysisLp(a)
Higher levels indicates an independent risk factor cardiovascular diseaseLp(a)
Servers as a storage for apoproteins for other apoprotein containing vesiclesHDL
Intracellular cholesterol is exported out of the cellABC Transporter
Cholesterol is esterfied by removing a fatty acid from phosphotitdylylcholine (lecithin)Lecithin Cholesterol Acyl Transferase (LCAT)
LCAT is activated byApo A-I
Transfers cholesterol ester for triacylglercerol to VLDL, IDL, LDLCholesterol Ester Transfer Protein (CETP)
HDL2 interacts with this liver receptor and off-loads all contents to the liver and becomes nascent HDLSR-B1 receptor
Hepatic lipase breaks down triacylglycerol leavingHDL3
Reverse cholesterol transport is carried out byHDL3
Hormone that has a positive effect on LPL, CETP LDL receptor, and hepatic lipaseT3/T4
Hormone that has a negative effect on oxidation of LDL reducing the risk atherosclerosisT3/T4

Medications and Poisions

Question Answer
Inhibits absorption of cholesterol in the ilium of the small intestineEzetimibe
Competitive inhibitor of HMG CoA reductase which decreases farnesyl pyrophosphate (FPP) there by also decreases CoQ biosynthesisStatins
A treatment for epilepsy and depressionSyndopa (5-Hydroxytrypophan combined with Carbidopa (a peripheral decarboxylase inhibitor))
Pharmaceutical formulation of BH4 used to treat Non-classical PKUKuvan
Inhibitor of thioredoxin reductase and ribonucleotide reductase and is used to treat brain tumorsMotexafin Gadolinium
An inhibitor of ribonucleotide reductase that is used in myeloproliferative disorders and also used in sickle cell anemia as it increases HbFHydroxyuria
A nucleoside analogue and it irreversibly inhibit ribonucleotide reductaseGemcitabine
Inhibits xanthine oxidase and hence decreases uric acid formation. Treatment for hyperuricemiasAllopurinol
Blocks the reduction of dihydrofolate. Used as an anticancer drug.Methotrexate
A immunosuppressive drug used in treatment of rheumatoid arthritis, inhibits dihydroorotate dehydrogenase enzyme and hence inhibit de novo pyrimidine nucleotide biosynthesisLeflunomide