Examination 4: Chapters 22 through 28

This exam combines questions from exams given during past years. Remember that the final exam will also include questions from the board review book. The correct answer, relative objective, and percent of the class answering each question correctly is at the end of the examination. The mean score for the entire exam is also listed.

1. The enzyme that controls the rate at which metabolites flow through glycolysis is:
  1. Hexokinase
  2. Glucokinase
  3. Phosphoglycerate kinase
  4. Pyruvate kinase
  5. Phosphofructokinase-1
2. Which of the following is not a component of the Cori cycle:
  1. Aerobic glycolysis
  2. Blood lactate
  3. Gluconeogenesis
  4. Blood glucose
  5. Glycolysis in red blood cells
3. Your patient comes to the emergency room with a bleeding ulcer. She has felt bad for several days. She suffers from COPD smoking 2 packs per day. She appears cyanotic. You expect a high:
  1. Hematocrit (%)
  2. Venous hemoglobin (g/dL)
  3. Partial pressure of oxygen
  4. pH
  5. Blood lactate
4. If palmitoyl CoA undergoes beta-oxidation, the products will be:
  1. 8 NADH + 8 FADH2 + 9 Acetyl CoA
  2. 7 NADH + 7 FADH2 + 8 Acetyl CoA
  3. 8 NADH + 8 FADH2 + 8 Acetyl CoA
  4. 7 NADH + 7 FADH2 + 7 Acetyl CoA
  5. 7 NADH + 7 FADH2 + 6 Acetyl CoA
5. The following graph shows the increase of blood acetoacetate, beta-hydroxybutyrate, glucose and free fatty acids during a fast. Which of the following is CORRECT?
  1. Curve A represents glucose
  2. Curve B represents free fatty acid
  3. Curve B represents acetoacetate
  4. Curve C represents glucose
  5. Curve A represents beta-hydroxybutyrate
6. Medium chain acyl CoA (MCAD) deficiency results in:
  1. Increased blood glucose following a meal
  2. Increased ketone body synthesis during a fast
  3. Decreased levels of liver ATP during a fast
  4. Increased gluconeogenesis during a fast
  5. Increase ketone body synthesis following a meal
7. All other things being constant, an increase in stress hormones would result in an increase in:
  1. Fatty acid synthesis in adipose tissue
  2. Blood amino acids for gluconeogenesis
  3. Malonyl CoA concentrations in liver
  4. Protein synthesis in muscle
  5. Glycogen synthesis in muscle
8. During the series of events following an increase in insulin, all of the following occur EXCEPT:
  1. Insulin binds its receptor, causing the autophosphorylation of receptor subunits
  2. Active protein kinases can cause the induction/repression of genes
  3. Glucagon-stimulated phosphorylation is reversed by the effects of insulin
  4. Phosphorylation results in more glucose transporters in adipose tissue cells
  5. Phosphorylation inhibits 3', 5'-phosphodiesterase
9. Which of the following is NOT a result of insulin binding to its receptor on a muscle cell?
  1. The receptor undergoes a change in conformation
  2. The receptor autophosphorylates tyrosyl residues
  3. Phosphorylation of the insulin receptor substrate (IRS) is increased
  4. More glucose transporters are inserted into the membrane
  5. G-protein and adenylate cyclase are activated
10. In a patient with NIDDM who has started taking a sulfonylurea drug, which of the following is part of the mechanism?
  1. The sulfonylurea drug binds to a calcium channel
  2. The sulfonylurea drug causes the cell to become more polarized
  3. The sulfonylurea drug increases the concentration of intracellular calcium
  4. The sulfonylurea drug increases the permeability of the membrane to calcium
  5. The sulfonylurea drug inhibits membrane depolarization
11. Which of the following statements about glycogenolysis and glucose metabolism is TRUE?
  1. Glucose-6-phosphate from liver glycogen usually enters glycolysis
  2. Glucose-6-phosphate from muscle glycogen sometimes enters the blood
  3. Muscle cytosol contains glucose-6-phosphatase
  4. Liver glycogenolysis and glycolysis are not usually active at the same time
  5. Muscle glycolysis is inhibited by epinephrine
12. Which of the following events helps in the incorporation of blood glucose into muscle glycogen?
  1. Glucokinase produces glucose-6-phosphate
  2. UDP-glucose pyrophosphorylase produces glucose-1-phosphate
  3. Branching enzyme produces alpha-1,4-glucosidic bonds
  4. ATP is a substrate for glycogen synthase
  5. Hydrolysis of pyrophosphate makes the overall reaction exergonic
13. All of the following activate muscle phosphorylase EXCEPT:
  1. AMP
  2. Ca++ - calmodulin
  3. fight or flight
  4. cyclic-AMP
  5. protein phosphatase
14. An absence of liver glucose-6-phosphatase is known as:
  1. Von Gierke's disease
  2. McArdle's disease
  3. Paget's disease
  4. Wernicke-Korsakoff syndrome
  5. Tay-Sachs disease
15. Which of the following glycolytic intermediates and enzymes are in the CORRECT sequence?
  1. Glucose-6-phosphate; Phosphofructokinase-1; Phosphoenolpyruvate; Glyceraldehyde-3-phosphate
  2. Hexokinase; DHAP(dihydroxyacetonephosphate); Fructose-6-phosphate; Glyceraldehyde-3-phosphate
  3. Glucose-6-phosphate; Glyceraldehyde-3-phosphate; Pyruvate kinase; Phosphoenolpyruvate
  4. Glucose-6-phosphate; Phosphofructokinase-1; Phosphoenolpyruvate; Fructose-2,6-bisphosphate
  5. Hexokinase; Phosphofructokinase-1; DHAP(dihydroxyacetonephosphate); Phosphoenolpyruvate

16. Which of the following glycolytic enzymes produce ATP during glycolysis
  1. Hexokinase
  2. Glucokinase
  3. Phosphofructokinase-1
  4. 3-phosphoglycerate kinase
  5. glyceraldehyde-3-phosphate dehydrogenase

17. The LDH reaction is reversible. Which of the following is not a substrate for this reaction?
  1. Lactate
  2. Pyruvate
  3. NAD+
  4. NADH + H+
  5. phosphoenolpyruvate

18. In a cell with mitochondria, NADH is produced during glycolysis. Since NADH cannot cross the mitochondrial membrane, the electrons of NADH are transferred to another compound which can cross the mitochondrial membrane. The compound is
  1. Aspartate
  2. Glutamate
  3. Malate
  4. Glutamine
  5. Asparagine
19. The activation of fatty acids involves all of the following players EXCEPT:
  1. ATP
  2. Fatty acyl CoA synthetase
  3. Enzyme bound fatty acyl AMP
  4. Pyrophosphate
  5. Fatty acyl carnitine

20. Regarding the CPT I reaction, which of the following is NOT TRUE?
  1. This reaction is necessary before activated fatty acids can pass into the matrix from the cytosol
  2. CPT I is embedded in the outer mitochondrial membrane
  3. CPT I is inhibited by malate
  4. CPT II transfers the acyl group from acylcarnitine
  5. CPT I causes the transfer of fatty acid from acyl-CoA to carnitine

21. Which of the following is NOT TRUE of beta-oxidation?
  1. Even chain fatty acids can be completely converted to acetyl CoA
  2. The process has four steps, two of which use NAD+ to oxidize
  3. For each NADH that is formed, 2.5 ATP can be generated
  4. The overall beta-oxidation of a 16 carbon fatty acyl CoA to 8 acetyl CoAs yields 28 ATP
  5. The beta-oxidation of an odd chain fatty acid would yield a propionyl CoA

22. Regarding the synthesis of ketone bodies, which of the following is TRUE?
  1. Ketone bodies are synthesized for stored energy during the fed state
  2. HMG CoA is an intermediate that can sometimes be used for cholesterol synthesis
  3. Acetoacetate is converted to beta-hydroxybutyrate spontaneously, yielding a CO2
  4. Ketone bodies are produced in the brain in response to starvation
  5. Acetoacetate can be converted to acetoacetyl-CoA in the liver

23. Increased blood insulin specifically plays a major role in all of the following EXCEPT:
  1. Glucose storage as glycogen in liver and muscle
  2. Conversion of glucose to triacylglycerols in liver
  3. Amino acid uptake and protein synthesis in skeletal muscle
  4. Promotion of the sparing of glucose utilized for energy in the brain during a fast
  5. Stimulation of transport of glucose into muscle and adipose tissue

24. In the synthesis of Insulin, which of the following is NOT TRUE?
  1. The alpha-cells of the pancreas are centered such that blood flow carries new glucagon over the beta-cells explaining the inhibitory effect of glucagon on insulin release
  2. Glucose is a major regulator of insulin release
  3. Cleavage of proinsulin to insulin yields a C-Peptide
  4. The chains of insulin are held together and in active conformation by disulfide bridges
  5. The A chain of insulin is shorter than the B chain

25. All the following are important in the glucagon second messenger cascade EXCEPT
  1. Glucagon binds causing the dissociation of GDP from and the association of GTP with the G-protein
  2. Adenylate cyclase catalyzes the conversion of ATP to cAMP
  3. Phosphodiesterase catalyzes the conversion of cAMP to AMP
  4. The receptor for glucagon undergoes an autophosphorylation which activates adenylate cyclase
  5. The cAMP binds to Protein Kinase A regulatory subunits, releasing catalytic subunits

26. In liver and muscle, glycogen degradation is characterized by all of the following EXCEPT:
  1. The activation by insulin of glycogen phosphorylase
  2. The yielding of glucose-1-phosphate residues by the enzyme glycogen phosphorylase
  3. The activity of a 4: 4- transferase to ensure the debranching
  4. The activity of a specific alpha-1, 6- glucosidase that yields free glucose residues
  5. The use of inorganic phosphate by glycogen phosphorylase

27. Which of the following is not true?
  1. Glucagon causes the breakdown of glycogen in liver to yield glucose to the blood
  2. Insulin inhibits glycogenolysis in the liver
  3. Epinephrine causes the glycogen in liver to be degraded to yield glucose to the blood
  4. Insulin causes the transport of glucose into muscle cells
  5. Epinephrine inhibits glycolysis of glucose in muscle cells

28. A bodybuilding enthusiast injected insulin and tried to work out for several hours. He continuously ingested the sports drink containing salts but no glucose, fatty acids, or protein. He passed out and went into a coma. All of the following contributed to his coma EXCEPT
  1. The insulin inhibited glycogenolysis
  2. The insulin inhibited gluconeogenesis
  3. The insulin inhibited hormones sensitive lipase
  4. The exercise used a lot of glucose
  5. The insulin inhibited glucose transporters

29. Concerning Otto shape, during his long distance run the change in the concentration of AMP ensures the increased uptake of fatty acyl CoA into his muscle mitochondria. This happens because the AMP-dependent protein kinase catalyzes the phosphorylation of
  1. ADP
  2. AMP
  3. Carnitine palmitoyltransferase
  4. Acetyl CoA carboxylase
  5. Malic enzyme
 
ANSWERS

Correct answers and percentage of the class answering correctly. As a reference point, previous classes scored a combined mean of 74.7% for questions 1 through 29.

1: E, 95%. Chapter 22, Objective 1: "To understand or describe any pathway, start with the following paradigm for aerobic glycolysis: Names: Functions: Substrates: Product: Control Enzymes: Regulation: Compartment: Tissues of interest:"

2: A, 81%. Chapter 22, Objective 14: "Explain the Cori Cycle."

3: E, 93%. Chapter 22, Objective 21: "Concerning Lopa Fusor...Explain why hemorrhage, anemia, COPD, or any combination of these three might result in lactic acidosis"

4: B, 75%. Chapter 23, Objective 7: "Given a saturated, straight chain fatty acid, be able to calculate the number of molecules of Acetyl-CoA, FADH2, and NADH produced by Beta-oxidation. How much ATP would this be equivalent to?"

5: E, 88%. Chapter 23, Objective 13: " What happens to the blood levels of fatty acids, glucose, and ketone bodies during an extended fast? Explain how the use of ketone bodies by the brain spares muscle protein."

6: C, 54%. Chapter 23, Objective 20: "Concerning Lofata Burne: Explain why medium chain acyl CoA (MCAD) deficiency would cause a decrease in ketone body synthesis during a fast. Also, from an energy point of view, explain why MCAD deficiency would increase the untilization of blood glucose by most tissues of the body and why gluconeogenesis in the liver is less than expected."

7: B, 80%. Chapter 26, "Objective 8: "What is the effect of stress hormones as a group upon the following metabolic pathways...The storage of glucose in glycogen, the mobilization of glucose from glycogen, the synthesis of fatty acids from glucose in the liver, the synthesis of triacylglycerols in liver and adipose tissue, the mobilization of free fatty acids from adipose tissue, the synthesis of proteins in most tissues, and the mobilation of amino acids from proteins for gluconeogenesis."

8: E, 56%, Chapter 26, Objectives 14 and 15: "To the extent that it is known, explain the series of events following an increase in insulin that results in more glucose transporters in muscle and adipose tissue cell membranes. Refer to figures 11.13 and 11.14 in your text and use the following terms: Insulin, insulin receptor, insulin-binding site, change in conformation, tyrosine kinase domains, auto-phosphorylation, IRS proteins, phosphorylation of IRS proteins, SH2 homology, activation of phosphatidylinositol 3' kinase, protein kinase B, glucose transporters (glut-4)." "To the extent that it is known, explain the effects of insulin upon cAMP cascade. How would insulin affect the concentration of cAMP? Name the enzyme. How would insulin affect the proteins phosphorylated as a result of the cAMP cascade? Name the types of enzymes."

9: E, 70%. Chapter 26, Objective 14: "To the extent that it is known, explain the series of events following an increase in insulin that results in more glucose transporters in muscle and adipose tissue cell membranes. Refer to figures 11.13 and 11.14 in your text and use the following terms: Insulin, insulin receptor, insulin-binding site, change in conformation, tyrosine kinase domains, auto-phosphorylation, IRS proteins, phosphorylation of IRS proteins, SH2 homology, activation of phosphatidylinositol 3' kinase, protein kinase B, glucose transporters (glut-4)."

10: C, 72%. Chapter 26, Objective 20: "Concerning Ann Sulin: She has type 2 and her blood insulin levels are within the normal range. Are her B-cells secreting enough insulin? Are her muscle and adipose cells responding normally to insulin?"

11: D, 59%. Chapter 28, Objective 2: "What are the functions of glycogen in liver and skeletal muscle? Why must glucose-6-phosphate produced from glycogen in muscle enter glycolysis? Why does glucose produced from glycogen in liver usually enter the blood stream instead of glycolysis?"

12: E, 33%. Chapter 28, Objective 5: "Describe the pathway for glycogen synthesis from glucose in liver and muscle: Name, Function, Substrates, Products, Control Enzyme, Regulation, Compartment, "

13: E, 67%. Chapter 28, Objective 18: "What are the three major activators of phosphorylase in muscle?"

14: A, 81%. Chapter 28, Objective 7: "Briefly, what is Von Gierke's disease? What is McArdle's disease?"

15. E, 96%, Chapter 22, Objective 1: "To understand or describe any pathway, start with the following paradigm for aerobic glycolysis. Names: Functions: Substrates: Product: Control Enzymes: Regulation: Compartment(s): Tissues of interest:

16. D, 83%, Chapter 22 Objective 6: "What is the enzyme that produces ATP from phosphoenolpyruvate in the glycolytic pathway? What reaction does this enzyme catalyze? Is the reaction reversible?"

17. E, 96%, Chapter 22, Objective 9: "What are the substrates and products of the LDH reaction? Is the reaction readily reversible?"

18. C, 90%, Chapter 22, Objective 8: "What is the function of the malate-aspartate shuttle? Name the substrates, products, and enzymes of the reactions necessary to transfer the electrons from the product of the glyceraldehyde-3-phosphate reaction to the substrate for the NADH Dehydrogenase in the electron transport chain."

19. E, 63%, Chapter 23, Objective 4: "What are the reactants and products of the fatty acyl CoA synthetase reaction?"

20.C, 80%, Chapter 23, Objective 5: "Describe the pathway for transport of fatty acyl CoA in the cytosol to fatty acyl CoA in the mitochondria. Use the terms carnitinepalmitoyltransferase I and II, carnitine, CoA, inner mitochondrial membrane, and carnitine acylcarnitine translocase, CoA in your explanation."

21. B , 40%, Chapter 23, Objective 7 : "Given a saturated, straight chain fatty acid, be able to calculate the number of molecules of Acetyl-CoA, FADH2, and NADH produced by B-oxidation. How much ATP would this be equivalent to?"

22. B, 80% Chapter 23, Objective 10: "Describe the pathway for the synthesis of ketone bodies by naming the substrates, the first ketone body made in the pathway, the next two ketone bodies made in the pathway, the intermediate in the pathway that can be used either for ketone body synthesis or cholesterol synthesis, and the enzyme that actually produces the first ketone body as a product. Where does this pathway reside?"

23. D, 82%, Chapter 26, Objectives for 4 and 14: "What is the effect of insulin upon the following metabolic pathways: the storage of glucose in glycogen; the mobilization of glucose from glycogen; the synthesis of fatty acids from glucose in the liver; the synthesis of triacylglycerols in liver and adipose tissue; the mobilization of free fatty acids from adipose tissue; the synthesis of proteins in most tissues; the mobilization of amino acids from proteins for gluconeogenesis; " "To the extent that it is known, explain the series of events following an increase in insulin that results in more glucose transporters in muscle and adipose tissue cell membranes. Refer to figures 11.13 and 11.14 in your text and use the following terms: Insulin, insulin receptor, insulin-binding site, change in conformation, tyrosine kinase domains, auto-phosphorylation, IRS proteins, phosphorylation of IRS proteins, SH2 homology, activation of phosphatidylinositol 3' kinase, protein kinase B, glucose transporters (glut-4)."

24. A, 64%, Chapter 26, Objective 9, 12 and 13, "Know the important events in the synthesis of insulin from synthesis of the preprohormone to precipitation in storage granules. What is the effect of the following upon insulin release and what is the hormone or metabolite directly affecting the beta-cells....a high carbohydrate meal, a high protein meal, starvation, trauma, or vigorous exercies? What is the effect of the following upon glucagon release and what is the hormone or metabolite directly affect the beta-cells...a high carbohydrate meal, a high protein meal, starvation, trauma, or vigorous exercise?"

25. D, 82%, Chapter 26, Objectives 16 and 17: " Be able to list all the intermediates in the signal transduction of glucagon from the binding of the ligand to the activation of a protein by phosphorylation. Use the terms: glucagon, receptor, conformation, Gs protein complex, GDP, GTP, dissociation a subunit, bg subunit, adenylcyclase, cAMP, protein kinase A, regulatory subunit, catalytic subunit, phosphorylation, activation or inhibition of regulatory enzymes." " One characteristic of a second messenger system is signal amplification! What does this statement mean?"

26. A, 83%, Chapter 28, Objectives 6: "Describe the pathway for glycogen degradation to glucose or glucose-6-phosphate in liver and muscle: Name, Function, Substrates, Products, Control Enzyme, Regulation, Compartment,."

27. E, 88%, Chapter 28, Objectives 10, and 11: "What is the effect of changes in the insulin/glucagon ratio, blood glucose or epinephrine upon glycogen synthesis and glycogen degradation in the liver?" " What is the effect of changes in the insulin, blood glucose or epinephrine upon glycogen synthesis or glycogen degradation in muscle?"

28. E, 82%, Chapter 28, Objective 20: "Concerning Jim Bodie: Jim injected insulin just before exercise. What were the effects upon the pathways and transport mechanisms of the liver and muscle that led to his hypoglycemic coma?"

29. D, 60%, Chapter 23, Objective 17: " Concerning Otto shape, during his long distance run the change in the concentration of AMP ensures the increased uptake of fatty acyl CoA into his muscle mitochondria. Explain this using the terms: muscle contraction, ATP, AMP, AMP-dependent protein kinase, acetyl CoA carboxylase, malonyl CoA, inhibition, carnitine:palmitoyltransferase I, and carnitine-acylcarnitine translocase"

gyonuschot@mailbox.une.edu

The following graph shows the increase of blood acetoacetate, beta-hydroxybutyrate, glucose and free fatty acids during a fast. Which of the following is CORRECT?
  1. Curve A represents glucose
  2. Curve B represents free fatty acid
  3. Curve B represents acetoacetate
  4. Curve C represents glucose
  5. Curve A represents beta-hydroxybutyrate