Lipid Metabolism: MCQs (Cholesterol, Triglycerides, and Other Lipids)

Multiple Choice Question on Lipid Metabolism (Cholesterol, Triglycerides, and Other Lipids)

1) The cholesterol serves as the precursor for the following biosynthetic pathways EXCEPT
a) Bile acid synthesis
b) Steroid hormone synthesis
c) Aldosterone synthesis
d) Thyroid hormone synthesis

2) Which of the following lipid act as lungs surfactant?
a) Phosphatidylcholine
b) Phosphatidylethanolamine
c) Ceramide
d) Phosphatidylinositol

3) Identify the simple lipid from the following
a) Lecithin
b) Fatty acid
c) Triacylglycerol
d) Steroids

4) All of the followings are complex lipids, except
a) Phosphatidic acid
b) Cerebroside
c) Cardiolipin
d) Cholesterol

5) Which of the following is an essential fatty acid?
a) Linolenic acid
b) Arachidonic acid
c) Oleic acid
d) Palmitic acid

6) Bile acid is derived from:
a) Cholesterol
b) Amino acids
c) Fatty acids
d) Bilirubin

7) Which of the following lipid is mostly present in mitochondrial membranes?
a) Lecithin
b) Cephalin
c) Cardiolipin
d) Ceramide

8) Insulin enhances the uptake of triacylglycerols in adipose tissues. Which of the following enzyme is activated that facilitates the uptake?
a) Hormone-sensitive lipase
b) Lipoprotein lipase
c) LCAT
d) Apo C-II

9) Familial hypercholesterolemia is a genetic disorder of cholesterol metabolism. The defect lies in
a) Transport of cholesterol from extrahepatic tissue to the liver
b) Impairment of cholesterol degradative pathway
c) Impairment of uptake of cholesterol by tissues
d) Impairment of HDL metabolism due to deficiency of Apo-A

10) Which of the following inhibits acetyl CoA carboxylase- a rate-limiting enzyme of fatty metabolism?
a) Citrate
b) ATP
c) Malonyl CoA
d) Acyl CoA

11) Acetyl CoA serves as the precursor for the synthesis of cholesterol, and the biosynthesis of cholesterol is tightly regulated. Which of the following step is a regulatory step of cholesterol biosynthesis. 
a) Formation 3-hydroxy-3-methylglutaryl COA
b) Formation of Mevalonate 
c) Formation of Isoprenoid Unit
d) Formation of Lansterol

12) The enzyme that regulates the biosynthesis of cholesterol also serves as the druggable target for the reduction of hypercholesterolemia (increase blood cholesterol). Identify the regulatory enzyme from the following option. 
a) HMG-CoA synthase
b) HMG- CoA reductase
c) Lansterol oxidase
d) Cholesterol synthase

13) Which of the following hormone increases the synthesis of cholesterol by regulating the enzyme HMG CoA reductase?
a) Insulin
b) Glucagon
c) Glucocorticoids
d) All of the above

14) Sterol Regulatory Binding Protein binds to DNA at the sterol regulatory element to increase the expression of HMG CoA reductase, and synthesis of cholesterol. The presence of a high cellular concentration of cholesterol
a) Increases the proteolytic cleavage, release, and shuttling of SREBP into the nucleus
b) Decreases the proteolytic cleavage and release of SREBP from ER
c) Activates SREBP by inducing the conformational change
d) Inhibit SREBP by competitively binding to DNA binding site of SREBP

15) Hormones such as insulin & glucagon regulate HMG CoA reductase by a phosphorylation and dephosphorylation process. Phosphorylation of HMG CoA reductase results in decreased enzyme activity.  Identify the correct statement from the following
a) Insulin inhibits kinase that phosphorylates HMG CoA reductase
c) Insulin activates kinase that phosphorylates HMG CoA reductase
c) Insulin activates the phosphatase that removes a phosphate group from HMG CoA reductase
d)  Insulin inhibits kinase that phosphorylates HMG CoA reductase

16) Hypercholesterolemia refers to a condition with high cholesterol with serum cholesterol level 
a)  >160 mg/dL
b) >200 mg/dL
c) >240 mg/dL
d) >280 mg/dL

17) Which of the following enzyme is responsible for the conversion of cholesterol to cholesterol ester inside the cells?
a) Lecithin Cholesterol Acyl Transferase
b) Acyl CoA Cholesterol Acyl Transferase
c) Cholesterol Esterase
d) None of the Above

18) Which of the following glycolytic intermediates serves as the precursor for the backbone for the synthesis of Triglycerides, Phosphatidylcholine, Phosphatidylethanolamine?
a) Glyceraldehyde-3-phosphate
b) Pyruvate
c) 1-3 Bisphosphoglycerate
d) 3-Phosphoglycerate

19) Ceramide is synthesized in the endoplasmic reticulum from the amino acid serine. Ceramide is an important signaling molecule (second messenger) that regulates the pathways including
a)  apoptosis
b) cell senescence
c) cell differentiation
d) All of the above

20) Identify the phospholipid that possesses a surfactant activity and synthesized shortly before parturition in full-term infants.  The deficiency of this phospholipid in the lungs causes respiratory distress syndrome.
a) Dipalmitoylphosphatidyletholamine
b) Ceramide
c) Dipalmitoylphosphatidylcholine
d) All of the above

21) A child is was brought to the hospital with the clinical presentation of mental retardation, blindness, and muscular weakness. The biochemical examination showed the accumulation of GM2 gangliosides in the tissues. What is the possible cause of the disease?
a) Tay Sachs Disease caused by Hexosaminidase A deficiency
b) Fabry Disease caused by Alpha-Galactosidase deficiency
c) Krabbe Disease caused by Beta-Galactosidase deficiency
d) Gaucher Disease caused by Beta-Glucosidase deficiency




Multiple Choice Answer Review
1-d) Thyroid hormone synthesis
2-a) Phosphatidylcholine
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
11- b) Formation of Mevalonate 
12-b) HMG- CoA reductase
13- a) Insulin
14- b) Decreases the proteolytic cleavage and release of SREBP from ER
15-c) Insulin activates the phosphatase that removes a phosphate group from HMG CoA reductase
16-c) >240 mg/dL
17-b) Acyl CoA Cholesterol Acyl Transferase
18- a) Glyceraldehyde-3-phosphate
19-d) All of the above
20-c) Dipalmitoylphosphatidylcholine
21-a) Tay Sachs Disease caused by Hexosaminidase A deficiency





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