1.29: Lipid Metabolism

1. Which is the main pathway of triglyceride digestion?
   1. triglycerides to 1, 3 diglycerides to 1-monoglyceride and fatty acids
   2. triglyceride to free fatty acids and glycerol
   3. triglycerides to 1, 2 diglycerides to 1-monoglycerides and fatty acids
   4. triglycerides to 1, 2 diglycerides to 2-monoglycerides and fatty acids
   5. triglycerides to 2, 3 diglycerides to 2-monoglycerides and fatty acids
2. After a meal, the bloodstream transports chylomicrons and VLDL to all tissues of the body. The principal site of uptake is:
   1. liver
   2. intestine
   3. kidney
   4. brain
   5. adipose tissue
3. The appearance of the plasma of a patient with markedly increased pre—beta lipoprotein, after it stands overnight at 4°C would be:
   1. clear
   2. turbid underneath a thick cream layer
   3. clear underneath a thick cream layer
   4. turbid with no cream layer
   5. clear to slightly cloudy
4. Triglycerides are hydrolyzed by the enzyme:
   1. glycerokinase
   2. amylase
   3. lipase
   4. hydrolase
   5. LCAT
5. On agarose gel lipoprotein electrophoresis, chylomicrons:
   1. migrate in the region of beta proteins
   2. migrate in the region of alpha₂ proteins
   3. remain at the origin
   4. migrate in the region of albumin
   5. migrate in the region of alpha₁ proteins
6. The drug “lovastatin” is used to lower serum LDL-cholesterol by:
   1. binding dietary cholesterol
   2. binding bile acids
   3. inhibiting LDL-uptake by cells
   4. inhibiting cellular cholesterol synthesis
   5. all of the above
7. Major risk factors for coronary artery disease include:
   1. genetic predisposition
   2. elevated serum cholesterol
   3. hypertension
   4. cigarette smoking
   5. all of the above
8. The currently accepted cut-off for classification of a high risk for coronary heart disease (CHD) is associated with which of the following sets of total cholesterol (IC) and LDL—cholesterol (LDL—C) values?
   1. TC>1500 mg/L, LDL-C>1000 mg/L
   2. TC>2000 mg/L, LDL-C>1300 mg/L
   3. TC>2000-2390 mg/L, LDL-C>1300- 1590 mg / L
   4. TC>2400 mg/L, LDL-C>1600 mg/L
   5. TC>2000 mg/L, LDL-C>1600 mg/L

Use the following Key to answer Questions 9-20:

1. 1, 2, and 3 are correct
2. 1 and 3 are correct
3. 2 and 4 are correct
4. only 4 is correct
5. all are correct

9. A lipoprotein electrophoretogram shows a heavily stained beta region. Which of the following chemistries should show a corresponding increase?:
   1. cholesterol
   2. fatty acids
   3. phospholipids
   4. triglycerides
10. The role of the liver in nutrition is to metabolize:
    1. cholesterol
    2. fatty acids
    3. phospholipids
    4. triglycerides
11. Effective way(s) of achieving a lowering of serum lipids are/is:
    1. diet
    2. exercise
    3. drugs
    4. vitamins
12. Cholesterol is essential for the normal functioning of an organism because it is:
    1. an essential component of all cell membranes
    2. the major component of chylomicrons
    3. a precursor of all steroid hormones
    4. the major gluconeogenic substrate of the liver
13. Very low density lipoproteins (VLDL) are distinguished from high density lipoproteins (HDL) by the following differences:
    1. VLDL have a density of less than 1.006; HDL have a density of greater than 1.063
    2. VLDL have a density of less than 1.0; HDL have a density greater than 1.0
    3. VLDL contain mostly triglycerides; HDL contain mostly phospholipids
    4. VLDL contain Apo A-I; HDL contain Apo B
14. Patients with hereditary hyperlipoproteinemia have an elevation of serum lipoprotein concentrations. Which of the following lipoprotein families serve as determinants of the abnormal 1ipoprotein patterns?:
    1. chylomicrons
    2. VLDL
    3. LDL
    4. HDL
15. Bile salts:
    1. are produced by the liver
    2. are strongly hydrophylic and hydrophobic
    3. emulsify dietary triglyceride
    4. have amphipathic properties
16. Which of the following statements are true concerning the low— density lipoprotein molecule? It:
    1. protects against heart disease
    2. is the primary vehicle for delivering cholesterol to
       peripheral tissues
    3. is the primary vehicle for removing cholesterol from
       peripheral tissues
    4. is greatly elevated in Type IIb familial hypercholesterolemia
17. Chylomicrons are elevated in plasma because of:
    1. Type I hyperlipoproteinemia
    2. intake of certain drugs that cause a secondary hypertriglyceridemia
    3. Type V hyperlipoproteinemia
    4. the sample being drawn following a meal
18. The major source(s) of blood cholesterol is (are):
    1. liver
    2. adipose cells
    3. intestine
    4. muscle
19. The primary factors that influence plasma cholesterol levels are:
    1. diet
    2. genetics
    3. gender
    4. plasma triglyceride levels
20. Lipoprotein particles are classified primarily according to their:
    1. density
    2. protein composition (% by weight)
    3. migration pattern in agarose
    4. site of synthesis

Answer

1. d (p. 605)
2. e (p. 605)
3. d (p. 619, 622)
4. c (p. 605, 612)
5. c (p. 613, 614)
6. d (p. 621)
7. e (p. 628)
8. e (p. 633)
9. b (p. 613)
10. e (p. 606)
11. a (p. 621, 635)
12. b (p. 606)
13. b (p. 613)
14. a (p. 619)
15. e (p. 605)
16. c (p. 616, 619)
17. e (p. 614, 619, 620)
18. b (p. 608)
19. a (p. 610-611)
20. b (p. 613)