Wang, 2000). View Answer, 6. Which of the following lipoproteins does not contain Apo B protein? A typical North American diet contains approximately 450mg of cholesterol per day (of which 55% is absorbed), while cholesterol synthesis on such a modest cholesterol diet is 11–13mg/kg/day. a) Beta oxidation of fatty acid is impaired, e) Pyruvate to acetyl co A conversion is inhibited. Which of the following is the major point of regulation on the pathway to cholesterol? Which of the following is the integral membrane protein of smooth ER? How is Squalene produced? 1) Which of the following is the best marker for the diagnosis of Acute pancreatitis? - Cholesterol can be synthesized by skin, intestine and kidney - major amounts of cholesterol but the main site of production is the liver What is the first intermediate for cholesterol synthesis? … Our online cholesterol trivia quizzes can be adapted to suit your requirements for taking some of the top cholesterol quizzes. In cholesterol synthesis, six molecules of isopentenyl phosphate condense to form squalene, which is converted to lanosterol and then to cholesterol by a series of enzymatic reactions. d) Methane Which of the following statements best describes the bile salts? All the carbons of cholesterol are derived from acetyl-CoA. b) Squalene. View Answer, 7. [1 kg] [1 g] [2 g] [2 kg] 7 people answered this MCQ question 1 g is the answer among 1 kg,1 g,2 g,2 kg for the mcq In adults, synthesis of cholesterol per day is about; b) Isoprene The biosynthesis pathway of cholesterol is endergonic which require ATP. Cyclo-oxygenase is required for the production of which of these? c) Sterol nucleus without CH3 between C ring and D ring of cholesterol His mother reports that her infant has been irritable and lethargic over the past several days. a) Acetic acid The key enzyme in the regulation of fatty acid synthesis is A. acetyl CoA carboxylase B. AMP activated proteinkinase C. protein phosphatase D. none of these Answer & Explanation Answer: Option A 2. View Answer, 10. Disconnection: Synthetic steps for the disconnection shown: (3) Condensation of six isoprenoid units to form squalene. The resulting supernatant, a crude organelle fraction, was layered onto the sucrose density gradient (20–70%, wt/vol), and centrifuged at 113,000 × gfor 19 h at 4 C in a s… View Answer, 9. 5) – Which of the following is not needed for the de novo synthesis of fatty acids? 18) Which of the following statements best describes cholesterol ester transfer protein (CETP)? c) 10 Biological Oxidation and Electron transport chain, Gray Baby syndrome and the role of Glucuronic acid. The cholesterol biosynthesis pathway involves enzymes that are in the cytoplasm, microsomes (ER), and peroxisomes. a) 8 Data suggested that lanosterol, the first intermediate in the pathway that is cyclic instead of linear, was the key regulator, but the researchers knew that a slightly modified version of lanosterol might be … 1. c) HMG co-A reductase 3)  A molecule of Palmitic acid attached to carbon 1 of glycerol moiety of a triacylglycerol is ingested and digested. Squalene 10 carbon intermediate 15 carbon intermediate Which is the first intermediate in cholesterol synthesis? d) Plasma membrane Biochemistry Quizzes for CSIR NET Exam e) Pyruvate to acetyl co A conversion is inhibited. The infant is found to have a profoundly low serum glucose and ketone body level. Acetyl CoA Which of the following regulates the female reproductive cycle? Cholesterol is 27 carbon containing compound. Using in vitro and in vivo assays, we show that lanosterol, the first sterol intermediate in cholesterol synthesis, potently stimulates ubiquitination of reductase, whereas cholesterol has no effect at 10-fold higher concentrations. E) … e) Bile salts are synthesized from glycine and taurine. 20) A male infant is born with ambiguous genitalia (from lack of androgens such as testosterone) and several salt wasting (due to lack of aldosterone). c) Non-steroid anti-inflammatory drug Condensation with another isopentyl-PP yields farnesyl pyrophosphate. Lipid metabolism is the synthesis and degradation of lipids in cells where fat are broken down for energy. Generally, the receptors for steroid hormones reside at ___________ 14)- Which of the following is not an intermediate of pathway of cholesterol synthesis ? Which of the following molecular complexes in the blood carries the palmitate residue from the lumen of the gut to the surface of the gut epithelial cell? a) Thiolase To practice Biochemistry Question Bank, here is complete set of 1000+ Multiple Choice Questions and Answers. When Stearic acid is oxidized, how many Acetyl co A are produced? How many carbons are present in HMG co-A? © 2011-2020 Sanfoundry. She is diagnosed with acute cholecystitis (inflammation of the gall bladder).The gall stones can obstruct the gall bladder, leading to an inadequate concentration of bile salts in the intestine. She had successfully lost 10 pounds over the last month after the surgery due to mobilization of fat stores to provide acetyl co A and energy. Designed by Abhishek Kashyap | Copyright Reserved ©2020 Namrata Chhabra, Lipid Metabolism- Multiple choice questions- set-1. 19) An infant is born prematurely at 28 weeks and has developed increasing difficulty in breathing. To collect SGs, the insulin peak was identified in the fractionated samples (16). The phosphorylation reactions are required to solubilize the isoprenoid intermediates in the pathway. b) Glycerol derivatives Aspirin is a non-steroidal anti-inflammatory drug that inhibits cyclooxygenase enzyme (COX). 8) Which of the following is the key regulatory enzyme of fatty acid synthesis? e) 7- dehydro cholesterol The third reaction is the committed step: the reduction of HMGCoA to mevalonate, for which two molecules of NADPH each donate two electrons. c) Lanosterol. Synthesis of cholesterol begins with the transport of acetyl-CoA from within the mitochondria to the cytosol. He is diagnosed with a 3-β-hydroxylase deficiency. The essential intermediates in the pathway from acetate to cholesterol are ___________ Cholesterol Synthesis: Stage 3 Isoprenoids react with each other to form geranyl pyrophosphate. b) 3 17) In Abetalipoproteinemia (a rare disease), lipoproteins containing apo B are not formed and lipid droplets accumulate in the intestine and liver. Biochemistry Lipids Exam, Quiz on Lipids. a) Mevalonate. c) Cytoplasm What is the biochemical basis of infant’s symptoms? d) Pyruvate kinase Which is the first intermediate in cholesterol synthesis? It is absent among prokaryotes (bacteria and archaea), although there are some exceptions, such as Mycoplasma, which require cholesterol for growth. Taking aspirin has been shown to be cardioprotective in myocardial infarction. A disconnection of 1,4-diphenylbut-2-yne is given below followed by possible corresponding synthetic reactions. Cholesterol synthesis takes place in the cytoplasm and in the endoplasmic reticulum (ER). d) Amino alcohols Squalene synthase is a 47-kDa protein of the endoplasmic reticulum and catalyzes the first committed step in cholesterol synthesis. d) 6 How many carbons are present in geranyl pyrophosphate? b) Nuclear membrane Which of (a)-(d) does not include a suitable first reagent? Definition. These first two reactions, catalyzed by thiolase and HMG-CoA synthase, respectively, are reversible and do not commit the cell to the synthesis of cholesterol or other isoprenoid compounds. (4) Cyclization of squalene to give rise to the parent steroid, lanosterol. b) Ethylene This reaction comprises the second step in the mevalonate-dependent isoprenoid biosynthesis pathway. b) Sterol nucleus with two CH3 between C and D ring and A and B ring of cholesterol A comprehensive database of cholesterol quizzes online, test your knowledge with cholesterol quiz questions. Why are the intermediates of cholesterol synthesis pyrophosphates? a) Progesterone Save my name, email, and website in this browser for the next time I comment. a) It converts cholesterol from LDL to cholesterol esters, b) It is the major protein of Chylomicrons, c) It exchanges cholesterol esters from HDL for other lipids, e) It transfers cholesteryl esters from peripheral tissues to HDL. d) Sterol nucleus but lack the alkyl chain attached to the ring D of cholesterol Arachidonate has 20 carbon atoms with A. Which of the following glycolytic intermediates can be used for the synthesis of glycerol-3-P? a) 2 b) 3 c) 5 d) 6 View Answer. The major regulatory enzyme is HMG-CoA reductase. 6) Glycerol produced from hydrolysis of triglycerides in adipose tissue is a waste product, since it has to be in glycerol-3-P form and the enzyme for phosphorylation, glycerol kinase is absent in the adipose tissue. c) 5 c) Estrogens Metabolic Biochemistry > MCQ Lipid Synthesis > Flashcards Flashcards in MCQ Lipid Synthesis Deck (14) Loading flashcards ... A thioester derivative of D-β-hydroxybutyrate is an intermediate in the synthetic path, ... Cholesterol is synthesized from: A) acetyl-CoA. b) Testosterone Sanfoundry Global Education & Learning Series – Biochemistry. The key intermediates in cholesterol biosynthesis are HMG-CoA, mevalonic acid, isopentenyl pyrophosphate, and squalene. a) Thiolase The liver and intestine account for approximately 10% each of total synthesis in humans. C) lipoic acid. 16) Which of the following apo proteins is an activator of LCAT? Which of the following is the phospholipid of primary importance in surfactant? A simplified schematic of the pathway that displaces the most important steps is shown in Figure 3. a) 2 13) A 4 month -old infant presents with a seizure. advertisement. Lathosterol and desmosterol are intermediates that are commonly measured in blood samples. 1-d) Thyroid hormone synthesis 2-a) Phosphatidyl choline 3-c) Triacylglycerol 4-d) Cholesterol 5-a) Linolenic acid 6-a) Cholesterol 7-c) Cardiolipin 8- b) Lipoprotein lipase 9-c) Impairment of uptake of cholesterol by tissue 10­-d) Acyl CoA c) Squalene An important conversion of cholesterol that takes place is esterification with long-chain fatty acids (e.g., palmitic acid) in the endoplasmic reticulum, which blocks cholesterol’s polar head group and, thus, its inclusion as a membrane fluidity buffer. The rate limiting step in cholesterol synthesis occurs at the 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reducatase, HMGR, catalyzed step. 3 double bonds B. b) Fatty acid synthesis is impaired. all isoprenoids, including cholesterol, steroids, prenylated proteins, heine A, dolichol, ubiquinone, carotenoids, retinoids, chlorophyll and natural rubber (K.C. During reaction give off inorganic phosphate and make sure reaction only goes in one direction: Term. c) Adipolysis is inhibited. All the carbon atoms in the cholesterol is provided by acetate. Your email address will not be published. 6. HMG-CoA is an intermediate in both cholesterol synthesis … Take up the gi lipid metab & membrane lipids MCQ's below to see how well you understood the course. A little more than half the cholesterol of the body arises by synthesis (about 700 mg/d), and the remainder is provided by the average diet. The mevalonate pathway, also known as the isoprenoid pathway or HMG-CoA reductase pathway is an essential metabolic pathway present in eukaryotes, archaea, and some bacteria. a) Sterol nucleus with two alkyl chain attached to the ring D of cholesterol All Rights Reserved. His skin starts to turn blue from lack of oxygen(cyanosis). Cholesterol’s synthesis from zymosterol requires an additional two NADPH to rearrange/remove double bonds. Glycerol -3-P can still be produced in the adipose tissue through interconversion of one of the glycolytic intermediate. Definition. He is diagnosed with Respiratory distress syndrome due to deficiency of lung surfactant. Join our social networks below and stay updated with latest contests, videos, internships and jobs! This set of Biochemistry Question Bank focuses on “Biosynthesis of Cholesterol, Steroids and Isoprenoids”. Required fields are marked *. Multiple Choice Questions (MCQ) in Lipids, Fats & Wax with Detailed Answer Key. Participate in the Sanfoundry Certification contest to get free Certificate of Merit. Cholesterol is a precursor of Vit D and many steroid hormones like cortisol, estrogen, testosterone, etc. 12) An obese, 40- year-old woman, who recently underwent gastric bypass surgery, presents with severe vomiting due to rapid intake of large quantities of food, which must be avoided after gastric bypass surgery. Cholesterol also serves as a precursor for the biosynthesis of steroid hormones, bile acid and vitamin D.Cholesterol is the principal sterol synthesized by all animals. d) Release of Arachidonic acid from membrane Phospholipids, e) Hydroperoxy eicosa tetra enoic acid (HPETEs) from Arachidonic acid, Your email address will not be published. Analysis of intermediate metabolites in cholesterol biosynthesis suggests that the first oxidative step in cholesterol biosynthesis catalyzed by squalene monooxygenase (SQLE), an important regulator downstream HMG-CoA reductase in cholesterol synthesis, is reduced by degradation of SQLE upon elevation of cellular plasmalogen level. View Answer, 2. Cholesterol synthesis starts with acetyl-CoA, which is used to synthesize hydroxymethylglutaryl-CoA (HMG-CoA). a) Nucleoplasm For the production of 1 mole of cholesterol, 18 moles of Acetyl coA, 36 moles of ATP and 16 moles of NADPH are required. 21) A 20- year-old woman has a myocardial infarct and is given an Aspirin to chew. Explanation: The first intermediate in cholesterol synthesis is mevalonate. Prednisolone and prednisone are chemically ___________ View Answer, 8. b) HMG co-A synthase NADPH provides the reducing equivalents. 7) Which of the following enzymes is required for releasing the newly synthesized fatty acid from the fatty acid synthase complex? 10) Which of the following is a break down product of odd chain fatty acids? The essential intermediates in the pathway from acetate to cholesterol are _____ a) Acetic acid b) Ethylene β-sitosterol is a major phytosterol, that is a sterol found in plants. Oxidative Phosphorylation & Photophosphorylation, here is complete set of 1000+ Multiple Choice Questions and Answers, Prev - Biochemistry Questions and Answers – Biosynthesis of Membrane Phospholipids, Next - Biochemistry Questions and Answers – Overview of Nitrogen Metabolism, Biochemistry Questions and Answers – Biosynthesis of Membrane Phospholipids, Biochemistry Questions and Answers – Overview of Nitrogen Metabolism, Biochemistry Questions and Answers – Nitrogen Excretion and the Urea Cycle, Biochemistry Questions and Answers – Regulation of Oxidative Phosphorylation, Biochemistry Questions and Answers – ATP Synthesis – 2, Biochemistry Questions and Answers – Lipids as Signals, Cofactors, and Pigments, Best Reference Books – Chemistry of Lipids, Steroids and Hormones, Biochemistry – Advanced Questions and Answers, Biochemistry Questions and Answers – Analysis of Metabolic Control, Biochemistry Questions and Answers – Structural Lipids in Membranes, Biochemistry Questions and Answers – G Protein – Coupled Receptors and Second Messengers, Biochemistry Questions and Answers – Multivalent Scaffold Proteins and Membrane Rafts, Biochemistry Questions and Answers – Storage Lipids, Biochemistry Questions and Answers – Pentose Phosphate Pathway of Glucose Oxidation, Biochemistry Questions and Answers – Regulatory Enzymes, Biochemistry Questions and Answers – Protein Targeting and Degradation, Biochemistry Questions and Answers – Biosynthesis of Amino Acids, Biochemistry Questions and Answers – The Composition and Architecture of Membranes, Biochemistry Questions and Answers – Biosynthesis of Triacylglycerols, Biochemistry Questions and Answers – Biosynthesis of Fatty Acids and Eicosanoids.

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