Unit 2: Lipids - Practice Quiz

1 What is a fatty acid mainly composed of?

2 What does a double bond usually do to an unsaturated fatty acid chain?

3 A saturated fatty acid contains:

4 Why are some fatty acids called essential fatty acids?

5 Which of the following is an essential fatty acid?

6 A triacylglycerol is made from:

7 What is the main storage function of triacylglycerols?

8 Where are triacylglycerols primarily stored in the human body?

9 What is a major function of phospholipids?

10 Which part of a phospholipid is hydrophilic?

11 Which part of a phospholipid is hydrophobic?

12 The backbone of sphingolipids is usually:

13 Sphingomyelin is an example of a:

14 What carbohydrate component is present in glycolipids?

15 Glycolipids are especially important for:

16 Cholesterol belongs to which class of lipids?

17 Cholesterol is an important precursor for the synthesis of:

18 Eicosanoids are signaling molecules derived mainly from:

19 Which group includes eicosanoids?

20 Which is a function of lipids in the body?

21 A fatty acid contains 18 carbon atoms and one double bond between C9 and C10, with the double bond in the cis configuration. How would this fatty acid generally affect membrane fluidity compared with a saturated fatty acid of the same length?

22 Why does a fatty acid with 20 carbon atoms generally have a higher melting point than one with 16 carbon atoms when both are saturated?

23 A patient develops dry, scaly skin and impaired growth after consuming a diet lacking certain polyunsaturated fatty acids. Which dietary component would most directly prevent this deficiency?

24 Why must alpha-linolenic acid be obtained from the diet?

25 A triacylglycerol contains three fatty acids esterified to glycerol. Which change would most likely make it liquid at room temperature?

26 During prolonged fasting, adipose tissue releases fatty acids from triacylglycerol mainly to provide which function?

27 Why are triacylglycerols more efficient energy stores than glycogen on a mass basis?

28 A phospholipid is placed in water and spontaneously forms a bilayer. Which property best explains this behavior?

29 A membrane becomes unusually rigid at low temperature. Which modification would most effectively increase its fluidity?

30 Which phospholipid is commonly found in pulmonary surfactant and helps reduce surface tension in the alveoli?

31 What structural feature distinguishes sphingolipids from glycerophospholipids?

32 A defect in the degradation of sphingomyelin would most directly cause accumulation of which type of molecule in cells?

33 A glycolipid located on the outer surface of a plasma membrane most directly contributes to which process?

34 Which statement best distinguishes a ganglioside from a cerebroside?

35 How does cholesterol help stabilize a plasma membrane across different temperatures?

36 Which molecule can be synthesized from cholesterol in the human body?

37 Eicosanoids are commonly synthesized from which precursor fatty acid?

38 A drug inhibits cyclooxygenase enzymes. Which outcome is most directly expected?

39 A person has reduced absorption of dietary lipids after impaired bile secretion. Which nutrient absorption is also most likely reduced?

40 Why does adipose tissue provide useful thermal insulation in mammals?

41 Why does cis-unsaturation generally lower the melting point of a fatty acid more than an equivalent trans-unsaturation?

42 Compared with a saturated fatty acid of the same chain length, a polyunsaturated fatty acid is more susceptible to oxidative damage primarily because it has:

43 A person consuming adequate linoleic acid but no α-linolenic acid would be most directly limited in synthesizing which product?

44 Why can increased dietary omega-3 fatty acids alter inflammatory signaling even when total fatty-acid intake remains unchanged?

45 A triacylglycerol contains palmitate at -1, oleate at -2, and stearate at -3. Complete hydrolysis produces:

46 Why is triacylglycerol more energy-dense than glycogen on a mass basis?

47 A phospholipid has two unsaturated acyl chains instead of two saturated chains. Which membrane property is most likely to increase at physiological temperature?

48 Which feature best explains why phosphatidylcholine is usually zwitterionic but electrically neutral at physiological pH?

49 Phosphatidylinositol 4,5-bisphosphate is especially important in signaling because it can be:

50 Which structural change distinguishes a ceramide from sphingosine?

51 A defect in lysosomal degradation of sphingomyelin would most directly cause accumulation of:

52 Which statement best distinguishes glycosphingolipids from glycerophospholipids?

53 The carbohydrate portions of many glycosphingolipids are exposed on the extracellular surface because these lipids:

54 At temperatures below a membrane's phase-transition range, cholesterol generally prevents excessive membrane rigidification by:

55 Why can cholesterol decrease membrane permeability to small polar molecules without eliminating membrane fluidity?

56 A nonselective cyclooxygenase inhibitor decreases prostaglandin and thromboxane synthesis because it blocks conversion of arachidonic acid into:

57 Why can two tissues produce different eicosanoids from the same arachidonic-acid pool?

58 A cell exposed to prolonged cold increases the proportion of unsaturated phospholipid acyl chains. This response primarily illustrates:

59 A mutation prevents intestinal formation of mixed micelles. Which combined consequence is most likely?

60 Why are lipids effective signaling molecules despite being poorly soluble in water?