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2012-04-16 00:16:19
Systems SA2 2012 S2

Systems 2 SA2-2012
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  1. Your patient tells you that she is a Type 1 diabetic but has stopped her insulin. In the absence of treatment you expect that she will have all except one of the following:
    • A. Increased fatty acids in the blood
    • B. Increased blood glucose levels
    • C. Increased secretion of VLDL from the liver
    • D. Increased activity of lipoprotein lipase
    • E. Increased blood ketone bodies
  2. Correct Answer: D
    Insulin is required for normal LPL activity.
  3. The following mechanisms insure an adequate and constant supply of glucose to the brain, EXCEPT:
    • A. The brain glucose transporter has a low Km
    • B. The brain glucose transporter has a high Km
    • C. During a fast, the liver releases glucose into the circulation
    • D. During a fast, other organs cooperate to provide the liver with substrates to make glucose
    • E. The brain has a hexokinase with a low Km
  4. Correct Answer: B
  5. All except one of the following is correct. Plasma HDL:
    • A. Levels below 40 mg/dl are a risk factor for heart disease/heart attack.
    • B. Levels increase in response to severe exercise
    • C. Levels increase in response to niacin treatment
    • D. Increases oxidation of LDL in the artery wall
    • E. Is synthesized by the liver
  6. Correct Answer: D
    D is incorrect. HDL is thought to prevent LDL oxidation in the artery wall.
  7. Which of the following clinical presentations represents a complication of uncontrolled diabetes?
    • A. Skin paresthesia
    • B. Blindness
    • C. Gangrene of extremities
    • D. Heart attack
    • E. All of the above
  8. Correct Answer: E
  9. Which of the following statements about insulin is INCORRECT?
    • A. Insulin opposes the action of glucagon
    • B. Insulin stimulates the translocation of the glucose transporter Glut 4 to the cell surface
    • C. Insulin stimulates the dephosphorylation of key enzymes
    • D. Insulin stimulates the phosphorylation of key enzymes
    • E. Insulin is absent or ineffective in diabetes
  10. Correct Answer: D
  11. The reduction in neural tube defects by folic acid enrichment of grain products represents a major public health achievement. The following statements describe the biochemistry which underlies this achievement, EXCEPT:
    • A. Folic acid is required for the regeneration of methionine from homocysteine
    • B. Folic acid is required very early in pregnancy
    • C. Folic acid is required for transamination
    • D. Folic acid is required for the synthesis of purines and pyrimidines
    • E. Folic acid excess may mask Vitamin B12 deficiency
  12. Correct Answer: C
  13. Which of the following statements about management of phenylketonuria (PKU) is INCORRECT?
    • A. Dietary phenylalanine restriction must be started very early in order to prevent mental retardation
    • B. The diet is best if it contains no phenylalanine at all
    • C. PKU patients must avoid aspartame, a sweetener present in some sodas and food.
    • D. A correct mix of other amino acids and nutrients must be included in the diet
    • E. Tetrahydrobiopterin (BH4) is used to treat patients with dihydrobiopterin reductase deficiency and also some patients with phenylalanine hydroxylase deficiency
  14. Correct Answer: B
  15. Which is NOT a major function of insulin?
    • A. Activating glucose transporters for glucose entry in cells
    • B. Promoting glycogen synthesis and storage in the liver & muscles
    • C. Promoting glucose synthesis from proteins in the muscle tissues
    • D. Promoting triglyceride storage in adipose tissues
  16. Correct Answer: C
  17. Which of the following enzymes is NOT regulated by phosphorylation-dephosphorylation?
    • A. Glucose 6-phosphate dehydrogenase
    • B. Bifunctional enzyme
    • C. Glycogen phosphorylase
    • D. Glycogen synthase
    • E. Pyruvate kinase
  18. Correct Answer: A
  19. A 24 year old student has been feeling fatigued for the past week. He has also noticed yellowing of his eye sclera. He remembers eating at a local restaurant just before he got sick. He does not have any history of blood transfusion, IVDA or multiple sexual partners. His liver function tests are elevated. What disease does he most likely have and what is the most likely clinical course of his disease?
    • A. Hepatitis A. He will most likely recover with no complications.
    • B. Hepatitis A. He will most likely go on to develop chronic hepatitis.
    • C. Hepatitis C. He will most likely go on to develop chronic hepatitis.
    • D. Hepatitis C. He will most likely recover with no complications.
  20. Correct Answer: A
  21. Which of the following statements about ornithine is CORRECT?
    • A. Ornithine is a component of proteins
    • B. Ornithine can only be found in the cytosol
    • C. Ornithine can only be found in mitochondria
    • D. Ornithine serves as a platform for the formation of urea
    • E. Ornithine can be metabolized to generate ATP
  22. Correct Answer: D
  23. Regulation of glucose metabolism can take place by all the following mechanisms EXCEPT:
    • A. Allosteric effects on reversible reactions
    • B. Allosteric effects on irreversible reactions
    • C. Hormone-stimulated phosphorylation of key enzymes
    • D. Hormone-stimulated dephosphorylation of key enzymes
    • E. Km of glucose transporters
  24. Correct Answer: A
  25. Which of the following statements is false?
    • A. Alcoholic and nonalcoholic steatohepatitis cannot be reliably distinguished by histology
    • B. In alcoholic liver disease, steatosis (accumulation of lipid within cytoplasm of hepatocytes) is an irreversible phenomenon.
    • C. Histologic features of steatohepatitis include steatosis, ballooning hepatocytes, Mallory-bodies and pericellular fibrosis.
    • D. Non-alcoholic steatohepatitis is linked to metabolic syndrome (obesity, diabetes, etc)
  26. Correct Answer: B
  27. When long-term use the following hypoglycemic agents, which of these agents causes increased homocystein levels and male absorption of vitamin B12?
    • A. glipizide (glucotrol)
    • B. glimepiride (amaryl)
    • C. metformin (glucophage)
    • D. pioglitazone (actos)
    • E. miglitol (glyset)
  28. Correct Answer: C
  29. Which of the following clinical symptoms is not a complication of diabetes mellitus?
    • A. retinopathy
    • B. hypocholesterolemia
    • C. peripheral polyneuropathy
    • D. nephropathy
    • E. foot ulcer
  30. Correct Answer: B
  31. The core of plasma lipoproteins are likely to contain:
    • A. Phospholipids
    • B. Cholesterol esters
    • C. Proteins
    • D. Cholesterol
    • E. All of the above
  32. Correct Answer: B
  33. A 48-year-old woman has experienced episodes of sharp abdominal pain for the past month. On physical examination there is tenderness upon palpation of her right upper quadrant. Laparoscopic surgery is performed and her gallbladder is found to have multiple stones. Which of the following is the most likely risk factor for her disease?
    • A. Obesity
    • B. Alcohol use
    • C. Ulcerative colitis
    • D. Hepatitis B infection
  34. Correct Answer: A
  35. Which statement best describes the pentose phosphate pathway:
    • A. The first enzyme, glucose 6-phosphate dehydrogenase, is defective in millions of people
    • B. The pathway serves to produce NADPH
    • C. The pathway serves to produce NADH
    • D. All of the above
    • E. A and B
  36. Correct Answer: E
  37. All of the following statement describing the mechanism of action of sulfonylureas are correct, except:
    • A. stimulate insulin release by depolarization of islet β cells
    • B. depress glucagons release
    • C. enhance the activity of endogenous insulin in target tissues
    • D. stimulate ATP-sensitive K+ channel, and subsequently cause Ca++ influx
  38. Correct Answer: D
  39. Which of the following statements about viral hepatitis is true?
    • A. The histologic features of acute and chronic hepatitis are distinct among different viral types and therefore histologic features are very reliable in determining the etiology of hepatitis.
    • B. All forms of viral hepatitis (including hepatitis A, B, C and E) will result in chronic hepatitis.
    • C. Chronic hepatitis is defined by clinical evidence of liver disease for >6 weeks
    • D. Clinical studies (serology and molecular studies) are required to establish etiology of hepatitis, since there is marked overlap in histologic features among different etiologies
  40. Correct Answer: D
  41. Which of the following statements is CORRECT?
    • A. Glucagon stimulates the dephosphorylation of key enzymes
    • B. Enzymes regulated in glycolysis are the same ones regulated in gluconeogenesis
    • C. Glucose 6-phosphatase is a liver enzyme that ensures an adequate supply of blood glucose, even when we don’t eat
    • D. Insulin stimulates the phosphorylation of key enzymes
    • E. Glycogen phosphorylase is the key enzyme for the synthesis of glycogen
  42. Correct Answer: C
  43. Fasting increases the glucagon:insulin ratio in plasma and this alters lipid metabolism in the liver and adipose tissue. Such changes include all but one of the following:
    • A. Inactivation of acetyl CoA carboxylase (ACC) in the liver.
    • B. Increased hepatic synthesis of malonyl CoA and fatty acids.
    • C. Activation of lipases in adipose tissue.
    • D. Elevated plasma FFAs
  44. B is incorrect, as fasting decreases hepatic ACC, malonyl CoA and fatty acid synthesis.
    Correct Answer: B
  45. Which of the following statements about nutrition is INCORRECT?
    • A. Protein deficiency is not rare in the USA
    • B. Protein deficiency, when very severe, causes edema
    • C. Humans rely on diet to supply the essential amino acids
    • D. A healthy adult is said to be in nitrogen balance when intake and excretion of nitrogen are equal.
    • E. Adult athletes require the most protein per kg body weight
  46. Correct Answer: E
  47. Which of the following statements is true?
    • A. Islet cells of pancreas are exocrine cells which secrete pancreatic enzymes into the duodenum
    • B. Acinar cells of pancreas are endocrine cells which secrete hormones into the circulatory system
    • C. Chronic pancreatitis is characterized by acinar atrophy and fibrosis
    • D. One of the risk factor for cholesterol gallstones is male gender
  48. Correct Answer: C
  49. Which of the following statements about viral hepatitis is true?
    • A. Preventive vaccines are available for hepatitis C, but not hepatitis B
    • B. Hepatitis C is generally transmitted through fecal-oral transmission
    • C. The chance of developing chronic hepatitis is higher in hepatitis B than hepatitis C
    • D. Hepatitis B is transmitted through blood and therefore healthcare workers are at increased risk of exposure.
  50. Correct Answer: D
  51. Which statement is TRUE about type 2 diabetes?
    • A. It involves autoimmune pancreatic beta cell destruction
    • B. It is always associated with rapid onset of symptoms & clinical signs
    • C. It is not ketoacidosis prone
    • D. It requires insulin replacement as first line treatment
  52. Correct Answer: C
  53. Which of the following statements about the urea cycle is INCORRECT?
    • A. The urea cycle occurs partly in the cytosol and partly in mitochondria
    • B. The urea cycle detoxifies NH4+
    • C. The urea cycle is regulated, directly or indirectly, by the amount of protein consumed
    • D. The urea cycle generates ATP
    • E. The urea cycle can malfunction in genetic or non-genetic diseases
  54. Correct Answer: D
  55. Which of the following statements BEST describes protein metabolism?
    • A. Protein breakdown in proteasomes is fast and selective
    • B. Protein breakdown in lysosomes is fast and selective
    • C. Most proteins have similar half-lives
    • D. Not all amino acids can be broken down by humans
    • E. Active proteases are secreted by the exocrine pancreas
  56. Correct Answer: A
  57. Lipoprotein lipase hydrolyses triglycerides in:
    • A. HDL
    • B. VLDL
    • C. LDL
    • D. All of the above
  58. Only B is correct. Although LPL also hydrolyzes TG in chylomicrons.
    correct Answer: B
  59. Statins have proven useful in the treatment of certain patients. They can be used effectively for patients with;
    • A. Homozygous familial hypercholesterolemia
    • B. Chylomicronemia resulting from loss of LPL activity
    • C. Heterozygous familial hypercholesterolemia
    • D. All of the above
  60. C is correct. Statins function to lower LDL in patients who have one or two normal LDL receptor genes. Thus Statins are not useful for homozygous familial hypercholesterolemics (both LDLR genes are defective) or for lowering chylomicrons as a result of defective LPL.
    Correct Answer: C