Questions:

1. When the liver converts excess glucose into fatty acids, all of the following are true EXCEPT
  1. Glucose is converted by glycolysis into pyruvate in the cytosol
  2. Pyruvate is converted to acetyl CoA by pyruvate dehydrogenase in the cytosol
  3. Acetyl CoA and oxaloacetate form citrate that leaves the mitochondria
  4. Citrate lyase converts citrate, CoA and ATP into oxaloacetate, acetyl CoA, ADP and Pi
  5. The acetyl CoA is converted to palmitate and the oxaloacetate is converted to pyruvate
2. When the liver converts excess glucose into fatty acids, all of the following are true EXCEPT
  1. The control enzyme is acetyl CoA carboxylase
  2. The enzyme is activated by protein phosphatase
  3. Protein phosphatase is activated as a result of glucagon binding to liver cells
  4. The control enzyme converts ATP, CO2, and acetyl CoA into malonyl CoA, ADP, and Pi
  5. The concentrations of glucagon, epinephrine, or AMP are low because high concentrations would inhibit the control enzyme
3. Concerning the fatty acid synthase complex, all of the following are true EXCEPT
  1. Products include NADP+ and CoA
  2. Products include stearate (C18:0) and CO2
  3. Substrates include acetyl CoA
  4. Substrates include malonyl CoA
  5. Substrates include NADPH
4. Acyl carrier protein and CoA have all of the following in common EXCEPT
  1. Both incorporate ADP into their structure
  2. Both incorporate pantothenic acid into their structure
  3. Both have a functional SH group (thiol group)
  4. Both form thioester bonds with fatty acids
  5. Both form high-energy bonds with fatty acids
5. The fatty acids produced by the fatty acid synthase complex are not substrates for beta-oxidation because
  1. They are immediately activated to palmitoyl CoA
  2. Acetyl CoA, one substrate for the fatty acid synthase complex, inhibits carnitine: palmitoyltransferase-2
  3. High NADPH, a requirement for fatty acid synthesis, inhibits beta-oxidation
  4. High glucagon causes phosphorylation of acetyl CoA carboxylase whenever fatty acid synthase is active
  5. The product of the control step for fatty acid synthesis also inhibits carnitine: palmitoyltransferase-1
6. Where does the elongation of most fatty acids take place?
  1. Cytosol
  2. Mitochondria
  3. Nucleus
  4. VLDL
  5. Endoplasmic reticulum
7. Where does the desaturation of fatty acids take place in humans?
  1. Cytosol
  2. Nucleus
  3. Mitochondria
  4. VLDL
  5. Endoplasmic reticulum
8. All of the following statements about essential fatty acids are true EXCEPT
  1. They can not be synthesized by humans cells
  2. They are essential for the synthesis of some prostaglandins and other eicosanoids
  3. They contain omega-3 or omega-6 double bonds
  4. They contain at least 4 double bonds
  5. They are linoleic and linolenic acid
9. Starting with an intermediate in glycolysis and acyl CoA, all of the following are intermediates in the synthesis of triacylglycerols EXCEPT
  1. Glycerol-3-phosphate
  2. Monoacylglycerol phosphate
  3. Monoacylglycerol
  4. Diacylglycerol phosphate
  5. Diacylglycerol
10. During fatty acid mobilization, glycerol is used by the liver for gluconeogenesis because adipose does not have
  1. Glycerol kinase
  2. Hormone sensitive lipase
  3. Protein kinase A
  4. Phosphofructokinase-1
  5. Glycerol transporters
11. All of the following stimulate the storage of triacylglycerol in adipose tissue following a high carbohydrate meal EXCEPT
  1. A high insulin/glucagon ratio
  2. The activation of lipoprotein lipase
  3. Increased concentration of Glut4 transporters in the membrane
  4. Inhibition of glycolysis
  5. Increased synthesis of glycerol phosphate by glycerol-3-phosphate dehydrogenase
12. When the concentration of epinephrine or glucagon is high, they bind to receptors on adipose cell membrane and all of the following can be expected to occur EXCEPT
  1. The cAMP cascade activates hormone sensitive lipase
  2. Triacylglycerol is hydrolyzed to free fatty acids and glycerol
  3. Free fatty acids are carried to most tissues of the body by albumin
  4. Fatty acids are activated, enter the mitochondria, and are oxidized by beta-oxidation and the TCA cycle
  5. Increased Β-oxidation increases glycolysis in resting muscle
13. All of the following are glycerophospholipids that are typically found in the cell membrane EXCEPT
  1. Phosphatidylcholine (lecithin)
  2. Phosphatidylethanolamine
  3. Phosphatidylserine
  4. Phosphatidylinositol
  5. Diphosphatidylglycerol (cardiolipin)
14. Phosphatidic acid is an intermediate in both the synthesis of triacylglycerol and glycerophospholipids (membrane lipids).  To convert phosphatidic acid to phosphatidyl choline, you would remove the phosphate and react diacylglycerol with
  1. ADP-choline
  2. UDP-choline
  3. TDP-choline
  4. GDP-choline
  5. CDP choline
15. Phosphatidic acid is an intermediate in both the synthesis of triacylglycerol and glycerophospholipids (membrane lipids).  To convert phosphatidic acid to phosphatidylinositol, you would react phosphatidic acid with
  1. CTP and then with inositol
  2. UTP and then with inositol
  3. CTP and then with inositol trisphosphate
  4. CDP and then with inositol trisphosphate
  5. UDP and then with inositol
16. In the synthesis of membrane lipids, what is the function of SAM?
  1. To add phosphate groups to phosphatidylinositol
  2. To convert phosphatidylethanolamine into phosphatidylserine
  3. To convert phosphatidylethanolamine into phosphatidylcholine
  4. To convert phosphatidylcholine into phosphatidylinositol
  5. To convert phosphatidylserine into phosphatidylethanolamine
17. All of the following statements are true EXCEPT.  There are a number of lipases that hydrolyze groups in glycerophospholipids in the cell membrane.  A lipase that released
  1. Arachidonate and monoacylglycerolphosphate would be phospholipase A2
  2. Inositol trisphosphate and diacylglycerol would be phospholipase C
  3. A phosphate that was attached to the number-2 (middle) carbon atom of glycerol would be phospholipase A1
  4. An acyl group was attached to the number-2 (middle) carbon atom of glycerol would be phospholipase A2
  5. A phosphate that was attached to diacylglycerol would be phospholipase C
18. Over the last six months, your patient has developed a habit of eating chocolates.  He is eating about 600 calories a day in chocolates and his diet contains about 400 extra calories a day.  He comes to you for advice because he does not want to “get fat.”  You would be safe in telling him all of the following EXCEPT
  1. His liver will convert excess carbohydrates in chocolates into fat that will be transported and stored in his fat (adipose) cells
  2. If he continues his present diet, he will gain another 15 pounds and then stop gaining weight
  3. He could continue one chocolate a day and not gain more weight if he will exercise vigorously every day
  4. If he consumes more calories than he uses, he will continue to gain weight.
  5. His best choice is to stop chocolates and exercise
19. Colleen Lakker was born 6 weeks prematurely and suffered from respiratory distress syndrome (RDS).  All of the following help to explain her problem EXCEPT
  1. She cannot get enough oxygen to her tissues or exhale enough CO2
  2. She cannot contract her alveoli (air sacks)
  3. The surface tension in the fluid inside her alveoli is too great
  4. She has not synthesized enough surfactants
  5. She has not synthesized enough dipalmitoylphosphatidylcholine, phosphatidylglycerol, cholesterol, and surfactant proteins
20. Colleen Lakker was born 6 weeks prematurely and suffers from respiratory distress syndrome (RDS).  An arterial blood sample revealed a low partial pressure of oxygen (pO2) and a slightly elevated partial pressure of carbon dioxide (pCO2).  Her arterial pH was low.  All of the following help to explain her condition EXCEPT
  1. Her hypoxia is inhibiting the cytochrome oxidase reaction in the electron transport chain
  2. The ATP to ADP ratio of most cells in her body will be low
  3. The TCA cycle and pyruvate dehydrogenase will be inhibited
  4. Phosphofructosekinase-1 and anaerobic glycolysis will be activated and produce lactic acid
  5. Respiratory alkalosis has somewhat compensated for the lactic acidosis

21. Refer to the following Figure for Questions 21 and 22. In which row is a structure for lecithin found?
  1. Row A
  2. Row B
  3. Row C
  4. Row D
  5. Row E
22. Refer to the following Figure for Questions 21 and 22. In which row is a structure for diacylglycerol found?
  1. Row A
  2. Row B
  3. Row C
  4. Row D
  5. Row E

Figure for Questions 21 and 22

Question 21, In which row is a structure for lecithin found?
Question 22, In which row is a structure for phosphatidic acid found?
A = Row A, B = Row B, C = Row C, D = Row D, E = Row E
Table of structures for question 21 and 22
23. During fasting or exercise, fatty acids need to enter the mitochondria. All of the following will increase entry EXCEPT
  1. insulin
  2. AMP
  3. increased active protein kinase A
  4. epinephrine
  5. glucagon in the liver
24. When the concentration of epinephrine or glucagon is high, they bind to receptors on adipose cell membrane and all of the following can be expected to occur EXCEPT
  1. Hormone-Receptor-Gαβγ-GDP + GTP = Hormone-Receptor + GDP + Gβγ +Gα-GTP
  2. Gα-GTP + Adenylate cyclase = Gα-GTP-Adenylate cyclase
  3. ATP = cAMP + PPiĀ 
  4. cAMP + PKARRCC = 2 cAMP-R + 2 PKA
  5. ATP + Lipoprotein Lipase (inactive) = Lipoprotein Lipase-Pi (active) + ADP

Answers:

1. Answer: B. Chapter 33, Objective 1: What is the pathway for the conversion of glucose to acetyl CoA in the cytosol in preparation for fatty acid synthesis? Back to question 1.
2. Answer: C. Chapter 33, Objective 2: Be able to write the equation for the control step in fatty acid synthesis. What is the name of the enzyme and how is this enzyme step controlled? Back to question 2.
3. Answer: B. Chapter 33, Objective 3: What are the substrates and products of the fatty acid synthase complex? Back to question 3.
4. Answer: A. Chapter 33, Objective 4: What do acyl carrier protein and CoA have in common? Back to question 4.
5. Answer: E. Chapter 33, Objective 5: What prevents the fatty acids made by fatty acid synthesis from undergoing B-oxidation? Back to question 5.
6. Answer: E. Chapter 33, Objective 6: Where does the elongation of most fatty acids take place? Back to question 6.
7. Answer: E. Chapter 33, Objective 7: Where does the desaturation of fatty acids take place in humans? Back to question 7.
8. Answer: D. Chapter 33, Objective 8: What are the essential fatty acids and why are they essential? Back to question 8.
9. Answer: C. Chapter 33, Objective 9: Starting with an intermediate in glycolysis and acyl CoA, be able to name the intermediates in the synthesis of triacylglycerols in liver and adipose tissue. Back to question 9.
10. Answer: A. Chapter 33, Objective 10: During fatty acid mobilization, glycerol is not used by adipose tissue but is used by the liver for gluconeogenesis. Why? Back to question 10.
11. Answer: D. Chapter 33, Objective 11: How does the insulin/glucagon ratio stimulate the storage of triacylglycerol in adipose tissue following a high carbohydrate meal? Back to question 11.
12. Answer: E. Chapter 33, Objective 12: Be able to list the sequence of events from the time epinephrine binds a receptor on the surface of an adipose cell until acetyl CoA is made in muscle or liver. Don't forget the key enzyme that controls the process. Back to question 12.
13. Answer: E. Chapter 33, Objective 13: Be able to name 4 glycerophospholipids found in cell membranes. Back to question 13.
14. Answer: E. Chapter 33, Objective 14: By this time, you know how to make phosphatidic acid from glucose. How would you make phosphatidylcholine from phosphocholine (head group) and phosphatidic acid? Back to question 14.
15. Answer: A. Chapter 33, Objective 15: How would you make phosphatidylinositol from inositol and phosphatidic acid? Back to question 15.
16. Answer: C. Chapter 33, Objective 16: In the synthesis of membrane lipids, what is the function of SAM? Back to question 16.
17. Answer: C. Chapter 33, Objective 17: What are the functions of phospholipase A1, Phospholipase A2, and Phospholipase C? Which one would release arachidonic acid? Which one would release diacylglycerol and inositol trisphosphate? Back to question 17.
18. Answer: B. Chapter 33, Objective 18: Concerning Percy Veere who is eating too much candy: Can he produce fat from a low fat, high carbohydrate diet? How about a high protein, low fat diet? Back to question 18.
19. Answer: B. Chapter 33, Objective 19: Concerning Colleen Lakker: What was the cause of respiratory distress syndrome of this premature infant? What specific compounds are missing? Are any derivatives of phosphatidic acid? Back to question 19.
20. Answer: E. Chapter 33, Objectives 20: Concerning Colleen Lakker who suffers from respiratory distress syndrome: Explain her lactic acidosis using what you have learned in previous chapters. Use the terms cytochrome oxidase, electron transport chain, NADH, Acetyl CoA, pyruvate dehydrogenase, ATP level, phosphofructokinase, anaerobic glycolysis, and lactate in your answer. Back to question 20.
21. Answer: B. Chapter 33, Objective 14 and Chapter 5, Objective 15: By this time, you know how to make phosphatidic acid from glucose. How would you make phosphatidylcholine from phosphocholine (head group) and phosphatidic acid? Be able to recognize the names of and the structures of the phosphatidic acid, phosphatidylcholine, and lecithin.
22. Answer: C. Chapter 33, Objective 9: Starting with an intermediate in glycolysis and acyl CoA, be able to name the intermediates in the synthesis of triacylglycerols in liver and adipose tissue.
23. Answer: A. Chapter 33, Objective 2: Be able to write the equation for the control step in fatty acid synthesis. What is the name of the enzyme and how is this enzyme step controlled?
24. Answer: E. Chapter 33, Objective 12: Be able to list the sequence of events from the time epinephrine binds a receptor on the surface of an adipose cell until acetyl CoA is made in muscle or liver. Don't forget the key enzyme that controls the process.