Chapter 10 Lipids
Multiple Choice Questions
1. Storage Lipids
Which of the following molecules or substances contain, or are derived from, fatty acids?
A) Beeswax
B) Prostaglandins
C) Sphingolipids
D) Triacylglycerols
E) All of the above contain or are derived from fatty acids.
2. Storage Lipids
Triacylglycerols are composed of:
A) a glycerol backbone.
B) three fatty acids.
C) amide linkages between the fatty acids and the glycerol.
D) A and B above.
E) A, B, and C above.
3. Storage Lipids
Which of the following is not a consequence of partial hydrogenation of vegetable oils?
A) Longer shelf life
B) Lower melting temperature
C) Reduction of some cis double bonds to single bonds
D) Conversion of some cis double bonds to trans double bonds
E) Increased risk of cardiovascular disease upon consumption by humans
4. Storage Lipids
Biological waxes are all:
A) triesters of glycerol and palmitic acid.
B) esters of single fatty acids with long-chain alcohols.
C) triesters of glycerol and three long chain saturated fatty acids.
D) sphingolipids.
E) None of the above
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5. Storage Lipids
Which of the following statements is true of lipids?
A) Many contain fatty acids in ester or amide linkage.
B) Most are simply polymers of isoprene.
C) Testosterone is an important sphingolipid found in myelin.
D) They are more soluble in water than in chloroform.
E) They play only passive roles as energy-storage molecules.
6. Storage Lipids
Which of the following statements concerning fatty acids is correct?
A) A fatty acid is the precursor of prostaglandins.
B) Phosphatidic acid is a common fatty acid.
C) Fatty acids all contain one or more double bonds.
D) Fatty acids are a constituent of sterols.
E) Fatty acids are strongly hydrophilic.
7. Structural lipids in membranes
Which of the following contains an ether-linked alkyl group?
A) Cerebrosides
B) Gangliosides
C) Phosphatidyl serine
D) Platelet-activating factor
E) Sphingomyelin
8. Structural lipids in membranes
Sphingosine is not a component of:
A) cardiolipin.
B) ceramide.
C) cerebrosides.
D) gangliosides.
E) sphingomyelin.
9. Structural lipids in membranes
Which of the following statements about membrane lipids is true?
A) Glycerophospholipids are found only in the membranes of plant cells.
B) Glycerophospholipids contain fatty acids linked to glycerol through amide bonds.
C) Lecithin (phosphatidylcholine), which is used as an emulsifier in margarine and chocolate, is a
sphingolipid.
D) Some sphingolipids include oligosaccharides in their structure.
E) Triacylglycerols are the principal components of erythrocyte membranes.
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10. Structural lipids in membranes
Which of the following is not a glycerophospholipid?
A) Phosphatidylcholine
B) Phosphatidylethanolamine
C) Phosphatidylserine
D) Cardiolipin
E) Ceramide
11. Structural lipids in membranes
Which of the following is true of sphingolipids?
A) Cerebrosides and gangliosides are sphingolipids.
B) Phosphatidylcholine is a typical sphingolipid.
C) They always contain glycerol and fatty acids.
D) They contain two esterified fatty acids.
E) They may be charged, but are never amphipathic.
12. Structural lipids in membranes
A compound containing N-acetylneuraminic acid (sialic acid) is:
A) cardiolipin.
B) ganglioside GM2.
C) phosphatidylcholine.
D) platelet-activating factor.
E) sphingomyelin.
13. Structural lipids in membranes
Which of the following answers is not true?
A) Phospholipase A1 hydrolyzes the fatty acid from the 1-position on the glycerol backbone.
B) Phospholipase B1 hydrolyzes the fatty acid from the 2–position on the glycerol backbone.
C) Phospholipase C hydrolyzes the complete phospho-head group from the glycerol backbone.
D) Phospholipase D hydrolyzes just the head group from the phospho-glycerol backbone.
14. Structural lipids in membranes
Which of the following statements about sterols is true?
A) All sterols share a fused-ring structure with four rings.
B) Sterols are found in the membranes of all living cells.
C) Sterols are soluble in water, but less so in organic solvents such as chloroform.
D) Cholesterol is the principal sterol in fungi.
E) The principal sterol of animal cells is ergosterol.
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15. Structural lipids in membranes
Fatty acids are a component of:
A) carotenes.
B) cerebrosides.
C) sterols.
D) vitamin D.
E) vitamin K.
16. Structural lipids in membranes
Which of the following is not true of sterols?
A) Cholesterol is a sterol that is commonly found in mammals.
B) Sterols are commonly found in bacterial membranes.
C) Sterols are more common in plasma membranes than in intracellular membranes (mitochondria,
lysosomes, etc.).
D) Serols are precursors of steroid hormones.
E) Sterols have a structure that includes four fused rings.
17. Structural lipids in membranes
Which of the following best describes the cholesterol molecule?
A) Amphipathic
B) Nonpolar, charged
C) Nonpolar, uncharged
D) Polar, charged
E) Polar, uncharged
18. Structural lipids in membranes
Tay-Sachs disease is the result of a genetic defect in the metabolism of:
A) gangliosides.
B) phosphatidyl ethanolamine.
C) sterols.
D) triacylglycerols.
E) vitamin D.
19. Lipids as signals, cofactors, and pigments
An example of a glycerophospholipid that is involved in cell signaling is:
A) arachidonic acid.
B) ceramide.
C) phosphatidylinositol.
D) testosterone.
E) vitamin A (retinol).
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20. Lipids as signals, cofactors, and pigments
Non-steroidal anti-inflammatory drugs (NSAIDS) like aspirin and ibuprofen act by blocking
production of:
A) biological waxes
B) prostaglandins
C) sphingolipids
D) vitamin D
E) none of the above
21. Lipids as signals, cofactors, and pigments
Which of the following is not a fat-soluble vitamin?
A) A
B) C
C) D
D) E
E) K
22. Lipids as signals, cofactors, and pigments
Which vitamin is derived from cholesterol?
A) A
B) B12
C) D
D) E
E) K
23. Lipids as signals, cofactors, and pigments
Identify the molecule(s) derived from sterols.
A) Arachidonic acid
B) Gangliosides
C) Phosphatidylglycerol
D) Prostaglandins
E) Cortisol
24. Working with lipids
Which of the following techniques is not commonly used to analyze lipid composition?
A) Selective extraction using apolar solvents
B) Adsorption chromatography
C) X-ray crystallography
D) Hydrolysis using enzymes with specificity for certain linkages
E) Mass spectroscopy
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Short Answer Questions
25. Storage lipids
Pages: 357–358 Difficulty: 1
Circle the fatty acid in each pair that has the higher melting temperature.
(a) 18:19 18:29,12
(b) 18:0 18:19
(c) 18:0 16:0
26. Storage lipids
Pages: 357–358 Difficulty: 2
Describe the dependence of the melting point of a fatty acid upon (a) chain length and (b)
unsaturation; (c) explain these dependencies in molecular terms.
27. Storage lipids
Page: 358 Difficulty: 1
What is the effect of a double bond on fatty acid structure?
28. Storage lipids
Pages: 360–361 Difficulty: 2
In cells, fatty acids are stored as triacylglycerols for energy reserves. (a) What is the molecule to
which fatty acids are esterified to form triacylglycerols? (b) Define the logic behind cells storing
fatty acids in esterified form.
29. Storage lipids
Pages: 361–364 Difficulty: 2
What is the most significant chemical difference between triacylglycerols and glycerophospholipids
that leads to their different functions?
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30. Storage lipids
Pages: 360–361 Difficulty: 2
Describe three functions of triacylglycerols in mammals and one function in higher plants.
31. Structural lipids in membranes
Page: 364 Difficulty: 2
What are the chemical components of a biological wax, and what is their general structure?
32. Structural lipids in membranes
Page: 364 Difficulty: 2
Draw the structure of phosphatidylserine in the ionic form it would have at pH 7.
33. Structural lipids in membranes
Page: 364 Difficulty: 3
Give the structure of phosphatidylethanolamine containing one palmitate and one oleate. Show the
ionic form expected at pH 7. How many ester bonds are there in this compound?
34. Structural lipids in membranes
Page: 264 Difficulty: 2
Draw the structure of phosphatidylcholine. Circle the part of the molecule that is polar and draw an
arrow to the part that is nonpolar.
35. Structural lipids in membranes
Page: 364 Difficulty: 2
Show the basic structure of all glycerophospholipids.
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36. Structural lipids in membranes
Page: 365 Difficulty: 3
What chemical features distinguish a plasmalogen from a common glycerophospholipid?
37. Structural lipids in membranes
Page: 366 Difficulty: 2
Show the structure of sphingosine and indicate the relationship between sphingosine and ceramide.
38. Structural lipids in membranes
Page: 366 Difficulty: 3
What chemical features distinguish a cerebroside from a ganglioside?
39. Lipids as signals, cofactors, and pigments
Pages: 370–375 Difficulty: 2
Match the compounds on the left with the important roles they play listed on the right. (Answers are
used only once.)
(a) prostaglandins ___ blood clotting
(b) vitamin E ___ intra-tissue messengers
(c) sphingolipids ___ necessary for sight
(d) thromboxanes ___ mediates pain and inflammation
(e) vitamin A ___ important component of myelin membranes
(f) steroids ___ reducing agent
40. Lipids as signals, cofactors, and pigments
Pages: 368–371 Difficulty: 2
The venom of some rattlesnakes contains phospholipase A2. a) Explain why a snake bite causes
rapid pain and inflammation. b) Based on your biochemical understanding of the mechanism of the
pain, suggest a possible treatment. c) If too much phospholipase A2 enters the bloodstream, the
significant accumulation of one of the products of the reaction acts as a powerful detergent, causing
the lysis of red blood cells and potential death. What is this dangerous product and what makes it
such a good detergent?
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41. Lipids as signals, cofactors, and pigments
Pages: 368 Difficulty: 3
Describe the differences between the glycosphingolipids corresponding to the A, B, and O human
blood group antigens.
42. Structural lipids in membranes
Page: 369 Difficulty: 2
Explain the cause of hereditary diseases of sphingolipid metabolism, such as Tay-Sachs and
Niemann-Pick diseases.
43. Lipids as signals, cofactors, and pigments
Pages: 373–375 Difficulty: 2
Match each of these vitamins with its biological role: Vitamins A, D, E, K.
____ blood clotting
____ vision
____ Ca2+ and phosphate metabolism
____ prevention of oxidative damage
44. Lipids as signals, cofactors, and pigments
Pages: 373–375 Difficulty: 2
Show the structure of isoprene; explain what is meant by isoprenoid compounds and give an example.
45. Lipids as signals, cofactors, and pigments
Pages: 373–375 Difficulty: 2
What do all these compounds have in common: vitamin A, vitamin K, ubiquinone, and dolichol?
46. Working with Lipids
Pages: 377–379 Difficulty: 2
Explain why extraction of lipids from tissues requires organic solvents.
47. Working with Lipids
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Pages: 377–378 Difficulty: 3
If beeswax, cholesterol, and phosphatidylglycerol were dissolved in chloroform, then subjected to
thin-layer chromatography on silica gel using a mixture of chloroform/methanol/water as the
developing solvent, which would move fastest?