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6.3 Lipid Biosynthesis — Test 1
Q1. Which statements about the regulation of HMG-CoA reductase are correct? 1) Depletion of ATP activates it; 2) Insulin activates and glucagon inhibits it; 3) Insulin inhibits and glucagon activates it; 4) Lovastatin and oxysterol inhibit it.✓ 1, 2 & 4 are correct
Q2. A physician prescribed a statin to a patient with myocardial infarction. What is the specific action of statins?✓ Statins inhibit HMG-CoA reductase
Q3. Statins regulate cholesterol biosynthesis by:✓ Competitive inhibition of HMG-CoA reductase
Q4. Synthesis of 1 mole of cholesterol requires:✓ 16 moles acetyl-CoA and 18 moles NADPH
Q5. Cyclooxygenase catalyzes the formation of prostaglandins from which precursor?✓ Arachidonic acid
Q6. The polyunsaturated fatty acid DHA in humans is synthesised from:✓ α-Linolenic acid
Q7. The enzyme that catalyzes the first step in the biosynthesis of plasmalogens is present inside the:✓ Peroxisome
Q8. Prostaglandins are rapidly metabolized to their inactive products in the:✓ Lungs
Q9. Which fatty acid is a precursor for prostaglandin biosynthesis?✓ Arachidonic acid
Q10. All active prostaglandins have at least one double bond between positions:✓ 13 and 14
Q11. Prostaglandin H2 synthase has two catalytic activities. They are:✓ Cyclooxygenase and peroxidase
Q12. Which of the following is a metabolic precursor of most steroid hormones?✓ Cholesterol
Q13. Prostaglandins and leukotrienes (bioactive lipids in inflammation) are formed from which fatty acid?✓ Arachidonic acid
Q14. Prostaglandins and leukotrienes are formed from which fatty acid? (variant)✓ Arachidonic acid
Q15. Which statement is NOT TRUE of the signalling molecules called eicosanoids?✓ Eicosanoids are stored in large amounts and released on demand
Q16. All active prostaglandins have at least one double bond between positions (variant):✓ 13 and 14