text: lung, and a needle biopsy specimen of the mass shows carcinoma. A pneumonectomy is performed, and examination of
  the hilar lymph nodes reveals a uniform, dark black cut surface. Which of the following factors most likely accounts for the
  28 A 44-year-old man has a history of poorly controlled diabetes mellitus leading to coronary artery disease. He now has
  decreasing cardiac output. An increase in which of the following substances in his blood is most indicative of reversible
  29 An experiment introduces a вЂњknockoutвЂќ gene mutation into a cell line. The frequency of shrunken cells with chromatin
  clumping and cytoplasmic blebbing is increased compared with a cell line without the mutation. Overall survival of the
  mutant cell line is reduced. Which of the following genes is most likely to be affected by this mutation?
  30 A tissue preparation is experimentally subjected to a hypoxic environment. The cells in this tissue begin to swell, and
  chromatin begins to clump in the nucleus. ATPases are activated, and ATP production decreases. Which of the following
  31 A chest radiograph of an asymptomatic 37-year-old man showed a 3-cm nodule in the middle lobe of the right lung. The
  nodule was excised with a pulmonary wedge resection, and sectioning showed the nodule to be sharply circumscribed
  with a soft, white center. Culture of tissue from the nodule grew Mycobacterium tuberculosis. Which of the following
  32 The nonpregnant uterus of a 20-year-old woman measures 7 Г— 4 Г— 3 cm. The woman becomes pregnant and just
  before delivery of a term infant, the uterus measures 34 Г— 18 Г— 12 cm. Which of the following cellular processes has
  33 A 40-year-old woman has had chronic congestive heart failure for the past 3 years. In the past 2 months, she
  macrophages. Which of the following subcellular structures in macrophages is most important for the accumulation of this
  34 In an experiment, a large amount of a drug is administered to subjects and is converted by cytochrome P-450 to a toxic
  metabolite. The accumulation of this metabolite leads to increased lipid peroxidation within cells, causing damage to cell
  membranes and cell swelling. Depletion of which of the following substances by this mechanism within the cytosol
  35 An experiment is conducted in which cells in tissue culture are subjected to high levels of ultraviolet radiant energy.
  Electron microscopy shows cellular damage in the form of increased cytosolic aggregates of denatured proteins. In situ
  hybridization reveals that protein components in these aggregates also are found in proteasomes. Which of the following
  substances is most likely to bind to the denatured proteins, targeting them for catabolism by cytosolic proteasomes?
  36 A 71-year-old man diagnosed with pancreatic cancer is noted to have decreasing body mass index. His normal cells
  comprising skeletal muscle undergo atrophy by sequestering organelles and cytosol in a vacuole followed by fusion with a
  lysosome. However, the cancer continues to increase in size. Which of the following processes is most likely occurring in
  37 A 5-year-old child ingests 50 iron tablets, each with 27 mg of iron. Within 6 hours the child develops abdominal pain
  and lethargy. On physical examination he is hypotensive. Laboratory studies show metabolic acidosis. Through formation
  38 A proponent of Malbec, Syrah, and Merlot wines (all reds) touts their contribution to longevity, but this wine aficionado
  also controls the caloric content of his diet such that his body mass index is <22. This lifestyle promotes increased insulin
  sensitivity and glucose utilization. He fully expects to live long because he has read that caloric restriction prolongs life. In
  this man, which of the following proteins will most likely mediate the effect of calorie restriction upon increased longevity?
  1 (C)вЂ‚Irreversible cell injury is associated with loss of membrane integrity. This allows intracellular enzymes to leak into the
  serum. All other morphologic changes listed are associated with reversible cell injury, in which the cell membrane remains
  2 (E)вЂ‚The liver is one of the few organs in the human body that can partially regenerate. This is a form of compensatory
  hyperplasia. The stimuli to hepatocyte mitotic activity cease when the liver has attained its normal size. Apoptosis is single
  cell death and frequently occurs with viral hepatitis. Dysplasia is disordered epithelial cell growth that can be premalignant.
  Fatty change can lead to hepatomegaly; this is not a regenerative process, but is the result of toxic hepatocyte injury.
  Hydropic change, or cell swelling, does not produce regeneration. Hepatocytes can reenter the cell cycle and proliferate to
  continued stress from hypertension is eventual heart failure with decreased contractility, but the cells do not decrease in
  size. Metaplasia of muscle does not occur, although loss of muscle occurs with aging as myofibers are replaced by fibrous
  tissue and adipose tissue. Hemosiderin deposition in the heart is a pathologic process resulting from increased iron stores
  4 (B)вЂ‚The valve is stenotic because of nodular deposits of calcium. The process is вЂњdystrophicвЂќ because calcium
  deposition occurs in damaged tissues. The damage in this patient is a result of the wear and tear of aging. Amyloid
  deposition in the heart typically occurs within the myocardium and the vessels. The amount of lipofuscin increases within
  myocardial fibers (not valves) with aging. Hereditary hemochromatosis is a genetic defect in iron absorption that results in
  extensive myocardial iron deposition (hemosiderosis). Fatty change is uncommonly seen in myocardium, but infiltration of
  5 (E)вЂ‚Cholesterol is a form of lipid commonly deposited within atheromas in arterial walls, imparting a yellow color to these
  plaques. Glycogen is a storage form of carbohydrate seen mainly in liver and muscle. Lipofuscin is a brown pigment that
  increases with aging in cell cytoplasm, mainly in cardiac myocytes and in hepatocytes. Hemosiderin is a storage form of
  iron that appears in tissues of the mononuclear phagocyte system (e.g., marrow, liver, spleen), but can be widely
  deposited with hereditary hemochromatosis. Immunoglobulin occasionally may be seen as rounded globules in plasma
  6 (E)вЂ‚The focal, chalky white deposits are areas of fat necrosis resulting from the release of pancreatic lipases in a patient
  with acute pancreatitis. Viral hepatitis does not cause necrosis in other organs, and hepatocyte necrosis from viral
  infections occurs mainly by means of apoptosis. Intestinal infarction is a form of coagulative necrosis. Tuberculosis
  produces caseous necrosis. Gangrenous necrosis is mainly coagulative necrosis, but occurs over an extensive area.
  7 (B)вЂ‚Intracellular mechanisms exist that deal with free radical generation, as can occur with radiant injury from irradiation.
  Glutathione peroxidase reduces such injury by catalyzing the breakdown of hydrogen peroxide. Phospholipases decrease