The Chemical nature of lipids MCQs With Answer introduction below helps B. Pharm students master lipid chemistry fundamentals essential for pharmacology, formulation, and biochemistry. This concise, informative guide covers fatty acid structure, triglycerides, phospholipids, sphingolipids, sterols, lipid classification, amphipathic behavior, metabolic reactions (saponification, esterification, oxidation), and analytical parameters like iodine and saponification values. Emphasis on structure–function relationships, nomenclature (omega, sn-positions), and lipid role in drug delivery equips students for exams and practical applications. The questions focus on mechanisms, analysis, and clinical relevance to deepen understanding. Now let’s test your knowledge with 50 MCQs on this topic.
Q1. What is the basic structural backbone of glycerophospholipids?
- Glycerol bound to three fatty acids
- Glycerol bound to two fatty acids and a phosphate-containing head group
- Sphingosine backbone with one fatty acid and a head group
- Steroid nucleus with hydroxyl group
Correct Answer: Glycerol bound to two fatty acids and a phosphate-containing head group
Q2. Which functional group links fatty acids to glycerol in triglycerides?
- Amide bond
- Glycosidic bond
- Ester bond
- Phosphodiester bond
Correct Answer: Ester bond
Q3. What does the iodine value of a fat measure?
- Degree of hydrolysis
- Degree of unsaturation (number of double bonds)
- Amount of free fatty acids
- Chain length distribution
Correct Answer: Degree of unsaturation (number of double bonds)
Q4. Which fatty acid is classified as essential for humans?
- Palmitic acid (C16:0)
- Oleic acid (C18:1, ω-9)
- Linoleic acid (C18:2, ω-6)
- Stearic acid (C18:0)
Correct Answer: Linoleic acid (C18:2, ω-6)
Q5. In fatty acid nomenclature C18:1 cis-9 indicates what?
- 18 carbons, 1 double bond at carbon 9 from carboxyl end, cis configuration
- 18 carbons, 1 double bond at carbon 9 from methyl end, cis configuration
- 18 carbons, 1 double bond at carbon 9 from carboxyl end, trans configuration
- 18 carbons, 1 double bond at carbon 9 from methyl end, trans configuration
Correct Answer: 18 carbons, 1 double bond at carbon 9 from carboxyl end, cis configuration
Q6. Which lipid class contains a sphingosine backbone?
- Glycerophospholipids
- Triacylglycerols
- Sphingolipids
- Sterols
Correct Answer: Sphingolipids
Q7. What is the role of bile salts in lipid digestion?
- Hydrolyze triglycerides into monoglycerides
- Act as emulsifiers to increase surface area for lipase action
- Inhibit pancreatic lipase
- Transport lipids in bloodstream
Correct Answer: Act as emulsifiers to increase surface area for lipase action
Q8. Which analytical parameter indicates the average molecular weight of triglycerides by measuring alkali required for saponification?
- Iodine value
- Peroxide value
- Saponification value
- Acid value
Correct Answer: Saponification value
Q9. Which statement about cholesterol is correct?
- It is a triglyceride with three fatty acids
- It contains a steroid nucleus and a single hydroxyl group
- It is amphipathic with two phosphate groups
- It is a glycerophospholipid found in lysosomes
Correct Answer: It contains a steroid nucleus and a single hydroxyl group
Q10. What does the term “amphipathic” describe in lipids?
- Lipids that are fully hydrophobic
- Lipids with both hydrophilic and hydrophobic regions
- Lipids that are charged positively only
- Lipids that cannot form membranes
Correct Answer: Lipids with both hydrophilic and hydrophobic regions
Q11. What is the primary product of triglyceride hydrolysis by pancreatic lipase?
- Free cholesterol
- Fatty acids and 2-monoglyceride
- Glycerophosphates
- Sphingosine and fatty acid
Correct Answer: Fatty acids and 2-monoglyceride
Q12. Which value increases when fats undergo oxidative rancidity?
- Saponification value
- Iodine value
- Peroxide value
- Refractive index
Correct Answer: Peroxide value
Q13. Which lipid is a major component of cell membranes and has a choline head group?
- Phosphatidylcholine
- Triglyceride
- Cholesteryl ester
- Wax
Correct Answer: Phosphatidylcholine
Q14. The omega (ω) numbering of fatty acids starts from which end?
- Carboxyl (acid) end
- Methylene (middle) group
- Methyl (terminal) end
- Glycerol backbone
Correct Answer: Methyl (terminal) end
Q15. Trans fatty acids are formed primarily by which industrial process?
- Saponification
- Hydrogenation of unsaturated fats
- Enzymatic esterification
- Hydrolysis with lipase
Correct Answer: Hydrogenation of unsaturated fats
Q16. Which lipid analysis technique separates lipids based on polarity and mobility on a stationary phase?
- Mass spectrometry
- Thin layer chromatography (TLC)
- Polymerase chain reaction (PCR)
- UV-Vis spectroscopy
Correct Answer: Thin layer chromatography (TLC)
Q17. Which head group characterizes phosphatidylserine?
- Choline
- Ethanolamine
- Serine
- Inositol
Correct Answer: Serine
Q18. Plasmalogens are a class of glycerophospholipids notable for which feature?
- Ether linkage at sn-1 position
- Three fatty acid chains
- Steroid backbone
- Sulfonate head group
Correct Answer: Ether linkage at sn-1 position
Q19. Which parameter measures free fatty acid content in a fat sample?
- Acid value
- Iodine value
- Saponification value
- Moisture content
Correct Answer: Acid value
Q20. Glycolipids in membranes often participate in what cellular function?
- Energy storage exclusively
- Cell recognition and signaling
- DNA replication
- Protein synthesis in ribosomes
Correct Answer: Cell recognition and signaling
Q21. Which enzyme catalyzes the formation of fatty acyl-CoA from free fatty acids?
- Fatty acid synthase
- Acyl-CoA synthetase (thiokinase)
- Acyltransferase
- Lipoxygenase
Correct Answer: Acyl-CoA synthetase (thiokinase)
Q22. Sphingomyelin contains which of the following head groups?
- Choline phosphate attached to sphingosine
- Glycerol backbone with two fatty acids
- Free cholesterol moiety
- Glucose residue only
Correct Answer: Choline phosphate attached to sphingosine
Q23. Which lipid class is most important for long-term energy storage in adipose tissue?
- Glycerophospholipids
- Triglycerides (triacylglycerols)
- Sphingolipids
- Phosphatidylinositol
Correct Answer: Triglycerides (triacylglycerols)
Q24. Eicosanoids are derived from which fatty acid precursor primarily?
- Palmitic acid
- Linoleic acid (precursor via arachidonic acid)
- Lignoceric acid
- Oleic acid directly
Correct Answer: Linoleic acid (precursor via arachidonic acid)
Q25. Which statement about cholesterol esters is true?
- They are formed by esterification of cholesterol with a fatty acid
- They are water-soluble carriers of cholesterol
- They have a glycerol backbone
- They are primary components of bile salts
Correct Answer: They are formed by esterification of cholesterol with a fatty acid
Q26. Which of the following best describes a wax?
- Triacylglycerol with three unsaturated fatty acids
- Long-chain fatty acid esterified to a long-chain alcohol
- Glycerophospholipid with a sugar head group
- Sphingolipid with a phosphate head group
Correct Answer: Long-chain fatty acid esterified to a long-chain alcohol
Q27. Which property increases with the degree of saturation of fatty acids?
- Iodine value
- Melting point
- Number of double bonds
- Susceptibility to oxidation
Correct Answer: Melting point
Q28. Which lipid assay measures peroxides formed in initial stages of lipid oxidation?
- Peroxide value
- Saponification value
- Iodine value
- Acid value
Correct Answer: Peroxide value
Q29. The SN-1, SN-2, and SN-3 positions refer to carbons on which molecule?
- Cholesterol ring carbons
- Glycerol backbone of triglycerides/glycerophospholipids
- Sphingosine double bond positions
- Fatty acid alpha, beta, gamma carbons
Correct Answer: Glycerol backbone of triglycerides/glycerophospholipids
Q30. Which lipid is most amphipathic and forms bilayers spontaneously in aqueous environments?
- Triacylglycerol
- Free fatty acid
- Phospholipid (e.g., phosphatidylcholine)
- Waxes
Correct Answer: Phospholipid (e.g., phosphatidylcholine)
Q31. Which reagent is commonly used to detect double bonds in fatty acids by addition reaction in the iodine value test?
- Sodium hydroxide
- Bromine or iodine monochloride
- Potassium permanganate
- Phenolphthalein
Correct Answer: Bromine or iodine monochloride
Q32. Which lipoprotein class is primarily responsible for reverse cholesterol transport from tissues to liver?
- Chylomicrons
- LDL (low-density lipoprotein)
- VLDL (very low-density lipoprotein)
- HDL (high-density lipoprotein)
Correct Answer: HDL (high-density lipoprotein)
Q33. Which fatty acid oxidation pathway occurs in peroxisomes for very-long-chain fatty acids?
- Beta-oxidation
- Alpha-oxidation
- Omega-oxidation
- Glycolysis
Correct Answer: Beta-oxidation
Q34. Which fatty acid configuration is more common in nature and affects membrane fluidity?
- Trans configuration
- Cis configuration
- Conjugated trans-cis configuration
- All are equally common
Correct Answer: Cis configuration
Q35. Which lipid-derived signaling molecules include prostaglandins and leukotrienes?
- Eicosanoids
- Steroid hormones
- Triglycerides
- Glycolipids
Correct Answer: Eicosanoids
Q36. The Bligh and Dyer method is used for what purpose?
- Hydrogenation of fats
- Extraction and purification of lipids from biological samples
- Synthesis of phospholipids
- Measurement of peroxide value
Correct Answer: Extraction and purification of lipids from biological samples
Q37. Which enzyme catalyzes the rate-limiting step in de novo fatty acid synthesis?
- Acyl-CoA oxidase
- Fatty acid synthase (FAS) complex, specifically acetyl-CoA carboxylase as regulator
- Hormone-sensitive lipase
- Lipoprotein lipase
Correct Answer: Fatty acid synthase (FAS) complex, specifically acetyl-CoA carboxylase as regulator
Q38. Which lipid is a major substrate for phospholipase A2?
- Triglyceride
- Phospholipid at the sn-2 position releasing arachidonic acid
- Sphingomyelin producing ceramide directly
- Cholesteryl ester generating cholesterol
Correct Answer: Phospholipid at the sn-2 position releasing arachidonic acid
Q39. Which fatty acid is commonly found at the sn-2 position of phospholipids and is a precursor to eicosanoids?
- Arachidonic acid (C20:4)
- Stearic acid (C18:0)
- Lauric acid (C12:0)
- Palmitoleic acid (C16:1)
Correct Answer: Arachidonic acid (C20:4)
Q40. Which transporter helps load triglycerides into chylomicrons within enterocytes?
- ACAT (acyl-CoA:cholesterol acyltransferase)
- MTP (microsomal triglyceride transfer protein)
- FABP (fatty acid binding protein) only
- Glucose transporter (GLUT2)
Correct Answer: MTP (microsomal triglyceride transfer protein)
Q41. What is the effect of hydrogenation on unsaturated fatty acids?
- Converts saturated fats to unsaturated fats
- Adds hydrogen to double bonds, increasing saturation and potentially forming trans isomers
- Removes fatty acid chains from glycerol
- Converts cholesterol to bile acids
Correct Answer: Adds hydrogen to double bonds, increasing saturation and potentially forming trans isomers
Q42. Which lipid class contains carbohydrate moieties attached to lipid portion and is abundant in nervous tissue?
- Phosphatidylcholine
- Glycosphingolipids (glycolipids)
- Triacylglycerols
- Cholesteryl esters
Correct Answer: Glycosphingolipids (glycolipids)
Q43. Which physical property of lipids determines their partitioning into organic versus aqueous phases (important in drug formulation)?
- pKa value
- Lipophilicity (partition coefficient, log P)
- Optical rotation
- Heat capacity
Correct Answer: Lipophilicity (partition coefficient, log P)
Q44. Which molecule acts as the backbone for sphingolipid synthesis?
- Glycerol-3-phosphate
- Sphingosine
- Cholesterol
- Glucose-6-phosphate
Correct Answer: Sphingosine
Q45. In thin layer chromatography (TLC), which lipid typically has the highest Rf value on a polar silica plate with a nonpolar solvent?
- Phospholipids
- Free fatty acids
- Triacylglycerols
- Glycolipids
Correct Answer: Triacylglycerols
Q46. Which biochemical test quantifies unsaponifiable matter such as sterols in a fat sample?
- Acid value
- Unsaponifiable fraction determination after saponification
- Iodine value directly measures sterols
- Peroxide value measures sterols
Correct Answer: Unsaponifiable fraction determination after saponification
Q47. Which enzyme catalyzes cholesterol esterification in plasma associated with HDL?
- Lecithin–cholesterol acyltransferase (LCAT)
- Acyl-CoA cholesterol acyltransferase (ACAT)
- HMG-CoA reductase
- Hormone-sensitive lipase
Correct Answer: Lecithin–cholesterol acyltransferase (LCAT)
Q48. Omega-3 fatty acids are associated with which beneficial pharmacological effect?
- Increase LDL oxidation
- Anti-inflammatory and cardioprotective effects
- Promote clot formation
- Inhibit bile salt synthesis
Correct Answer: Anti-inflammatory and cardioprotective effects
Q49. Which reaction converts triglycerides into glycerol and free fatty acids using a strong base?
- Hydrogenation
- Saponification
- Transesterification using acid catalyst
- Peroxidation
Correct Answer: Saponification
Q50. Which pharmacological formulation uses lipids to enhance solubility and delivery of poorly water-soluble drugs?
- Enteric-coated tablets only
- Lipid nanoparticles and self-emulsifying drug delivery systems (SEDDS)
- Immediate-release aqueous tablets
- Antacid suspensions without lipids
Correct Answer: Lipid nanoparticles and self-emulsifying drug delivery systems (SEDDS)
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