Lipids are a diverse class of biomolecules central to pharmacy, encompassing fatty acids, triglycerides, phospholipids and sterols. This introduction covers lipid chemistry, natural and industrial sources, extraction and preparation methods (Soxhlet, Folch, Bligh & Dyer, transesterification), analytical evaluation (iodine, saponification, peroxide, acid values; GC, HPLC, TLC), preservation and storage strategies (antioxidants, cold, inert atmosphere), therapeutic uses (omega‑3, lipid-based drug delivery, parenteral lipids) and commercial utility (soaps, emulsifiers, biodiesel, cosmetics). Emphasis is on practical assays, stability issues like oxidation and rancidity, and formulation applications relevant to B.Pharm practice. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which functional group links fatty acids to glycerol in triglycerides?
- Ester bond
- Amide bond
- Glycosidic bond
- Phosphodiester bond
Correct Answer: Ester bond
Q2. Which test is primarily used to assess the degree of unsaturation in a fat or oil?
- Iodine value
- Saponification value
- Peroxide value
- Acid value
Correct Answer: Iodine value
Q3. Which extraction method is based on continuous solvent reflux and is commonly used for solid samples?
- Soxhlet extraction
- Folch method
- Bligh and Dyer method
- Supercritical CO2 extraction
Correct Answer: Soxhlet extraction
Q4. During lipid oxidation, which product is measured by the peroxide value assay?
- Primary hydroperoxides
- Secondary aldehydes
- Free fatty acids
- Glycerol
Correct Answer: Primary hydroperoxides
Q5. Which reagent combination is characteristic of the Folch lipid extraction method?
- Chloroform:methanol (2:1)
- Hexane:isopropanol (3:1)
- Acetone:water (1:1)
- Ethyl acetate:ether (1:1)
Correct Answer: Chloroform:methanol (2:1)
Q6. What does a high saponification value indicate about the average molecular weight of fatty acids in a fat?
- Lower average molecular weight (shorter chains)
- Higher average molecular weight (longer chains)
- Greater unsaturation
- Higher peroxide content
Correct Answer: Lower average molecular weight (shorter chains)
Q7. Which analytical technique is most suitable for profiling individual fatty acids after conversion to methyl esters?
- Gas chromatography (GC)
- UV‑Vis spectrophotometry
- Fourier transform infrared (FTIR)
- Atomic absorption spectroscopy
Correct Answer: Gas chromatography (GC)
Q8. Which lipid class is a major component of cell membranes and acts as an emulsifier in formulations?
- Phospholipids
- Triacylglycerols
- Sterols
- Waxes
Correct Answer: Phospholipids
Q9. Which preservation strategy specifically prevents metal‑catalyzed lipid oxidation?
- Adding chelating agents like EDTA
- Hydrogenation of double bonds
- Heating to 100°C
- Adding surfactants
Correct Answer: Adding chelating agents like EDTA
Q10. Hydrogenation of vegetable oils is industrially used to:
- Reduce unsaturation and increase melting point
- Increase iodine value
- Directly form glycerophospholipids
- Convert triglycerides to free fatty acids only
Correct Answer: Reduce unsaturation and increase melting point
Q11. Which value indicates the amount of free fatty acids present in a lipid sample?
- Acid value
- Iodine value
- Saponification value
- Peroxide value
Correct Answer: Acid value
Q12. Transesterification of triglycerides with methanol and a base catalyst produces:
- Biodiesel (fatty acid methyl esters) and glycerol
- Free fatty acids and soap
- Phospholipids and cholesterol
- Hydroperoxides and aldehydes
Correct Answer: Biodiesel (fatty acid methyl esters) and glycerol
Q13. Which antioxidant is a natural tocopherol commonly used to protect lipids from oxidation?
- Vitamin E (alpha‑tocopherol)
- Butylated hydroxytoluene (BHT)
- Propyl gallate
- Butylated hydroxyanisole (BHA)
Correct Answer: Vitamin E (alpha‑tocopherol)
Q14. Which lipid measurement is most directly affected by the presence of conjugated double bonds?
- Iodine value gives altered readings
- Saponification value increases proportionally
- Peroxide value is unaffected
- Acid value decreases
Correct Answer: Iodine value gives altered readings
Q15. In clinical lipid profiling, elevated serum triglycerides primarily reflect:
- Increased circulating triacylglycerols
- High phospholipid concentration
- Elevated cholesterol esters only
- Excess free glycerol
Correct Answer: Increased circulating triacylglycerols
Q16. Which method separates lipids based on polarity on a silica plate and is useful for class identification?
- Thin‑layer chromatography (TLC)
- Gel permeation chromatography
- NMR spectroscopy
- Mass spectrometry without separation
Correct Answer: Thin‑layer chromatography (TLC)
Q17. Essential fatty acids that must be obtained from the diet include:
- Linoleic acid (omega‑6) and alpha‑linolenic acid (omega‑3)
- Palmitic acid and stearic acid
- Arachidic acid and behenic acid
- Oleic acid exclusively
Correct Answer: Linoleic acid (omega‑6) and alpha‑linolenic acid (omega‑3)
Q18. Which commercial use of lipids relies on saponification with strong alkali?
- Soap production
- Cosmetic emulsifier synthesis without saponification
- Generation of biodiesel by acid hydrolysis only
- Formation of liposomal drug carriers
Correct Answer: Soap production
Q19. What is the primary reason to store oil samples under nitrogen or argon?
- To reduce oxygen‑mediated oxidation
- To prevent microbial growth
- To increase iodine value
- To hydrogenate unsaturated bonds
Correct Answer: To reduce oxygen‑mediated oxidation
Q20. Which technique is best for determining molecular species of phospholipids in complex mixtures?
- Liquid chromatography coupled with mass spectrometry (LC‑MS)
- Simple titration for acid value
- Peroxide value titration
- Soxhlet extraction alone
Correct Answer: Liquid chromatography coupled with mass spectrometry (LC‑MS)
Q21. Which parameter increases when oils become rancid due to hydrolytic breakdown?
- Acid value increases
- Iodine value increases markedly
- Saponification value drops to zero
- Peroxide value becomes negative
Correct Answer: Acid value increases
Q22. In parenteral nutrition, which lipid formulation is commonly used as an energy source and essential fatty acid provider?
- Emulsified long‑chain triglyceride intravenous lipid emulsions
- Solid fat tablets
- Topical lipid creams only
- Hydrogenated vegetable oil suspension
Correct Answer: Emulsified long‑chain triglyceride intravenous lipid emulsions
Q23. Which commercial lipid derivative acts as an effective nonionic surfactant and emulsifier in pharmaceuticals?
- Polysorbates (e.g., Tween series)
- Sodium stearate only
- Cholesterol esters exclusively
- Glycerol monostearate never used
Correct Answer: Polysorbates (e.g., Tween series)
Q24. Which laboratory parameter is used to monitor secondary oxidation products like aldehydes?
- Anisidine value
- Iodine value
- Saponification value
- Peroxide value alone
Correct Answer: Anisidine value
Q25. What effect does partial hydrogenation often produce that is a health concern?
- Formation of trans fatty acids
- Complete removal of all fatty acids
- Conversion to phospholipids
- Increase in essential fatty acids
Correct Answer: Formation of trans fatty acids
Q26. Which solvent system is typical for separating neutral lipids from polar lipids in a biphasic extraction?
- Chloroform:methanol:water with phase separation
- Pure water extraction only
- Hexane:ethyl acetate without water
- Acetone:acetonitrile with no chloroform
Correct Answer: Chloroform:methanol:water with phase separation
Q27. Which lipid class contains a sphingoid base and is important in nervous tissue?
- Sphingolipids
- Triacylglycerols
- Triesters of cholesterol
- Simple wax esters
Correct Answer: Sphingolipids
Q28. For long‑term stability of purified oils, which combination is most appropriate?
- Antioxidant addition, cold storage, light‑proof container
- Heating to 60°C and storing in clear bottles
- Adding water and exposing to air
- Mixing with metal salts to stabilize
Correct Answer: Antioxidant addition, cold storage, light‑proof container
Q29. Which property is directly measured by the saponification value assay?
- Average chain length (molecular weight) of fatty acids
- Degree of unsaturation in fatty acids
- Peroxide concentration only
- Cholesterol content in serum
Correct Answer: Average chain length (molecular weight) of fatty acids
Q30. Lipid‑based drug delivery systems like liposomes primarily exploit which lipid property?
- Ability of amphiphilic lipids to form bilayers and encapsulate drugs
- High reactivity with oxygen to form peroxides
- Complete insolubility in all solvents
- Conversion to soaps under neutral pH
Correct Answer: Ability of amphiphilic lipids to form bilayers and encapsulate drugs
I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.
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