Bio 107 Exam #3, version 1 Answer key 

 

  1. D.  Question from the text website.
  2. C.  Negative feedback acts to maintain homeostasis and keep CO2 concentrations at their set point.
  3. C.  stratified = layers, cuboidal = boxlike
  4. C.  fibroblasts are a marker for loose connective tissue.  Slightly modified question from the text website.
  5. E.  The other answers only apply to some types of muscle fibers
  6. D.  Salivary amylase hydrolyzes starch in the mouth, digestion of the other molecules begins later in the digestive system.
  7. C.  Essential nutrients are not made in the body and must be obtained from food. 
  8. B.  Absorbed fats enter the lacteal in the villi of the small intestine and travel through the lymph system before entering the circulatory system.  Carbohydrates are immediately absorbed into the bloodstream.
  9. D.  Vitamin A is fat soluble and can be stored.  B1 is water soluble and any excess is excreted.  From the text website.
  10. D.  Bile salts surround fats and increase the surface area of the fat globules.  They are manufactured by the liver and stored in the gall bladder before release.
  11. B.  Cholecystokinin causes the release of bile and pancreatic enzymes, and does not influence release of pepsinogen
  12. D.  Many zymogens are only active at neutral pH.  One of the reasons that the pancreas secretes bicarbonate is to neutralize the acid chyme so the pancreatic zymogens can work. 
  13. D.  Disaccharidases are found attached to the walls of the lumen of the intestine.
  14. B.  Sunlight on the skin catalyzes the formation of vitamin D, which is necessary for absorption of calcium necessary to build strong bones.
  15. C.  An artery usually carries oxygenated blood, but there are exceptions such as in the pulmonary artery, so A is incorrect.  The most accurate definition is C.  Question from the text website.
  16. C.  See figure 42.10.
  17. B.  Oxygenated blood returns from the lungs to the left atrium (5), then to the left ventricle (6), and out through the aorta (3).
  18. E.  A four chambered heart keeps the oxygenated blood and deoxygenated blood from mixing in the ventricles.
  19. B.  This allows the atria to finish contracting and push the blood into the ventricles before the ventricles start to contract.
  20. D.  This is the chamber that pushes blood through the lungs.  Question from the text website.
  21. A.  Edema is an excess of fluid in the tissues.  Lower blood pressure reduces the amount of fluid pushed from the capillaries into the tissues.  The other choices either increase the fluid movement into the tissues or reduce the osmotic pressure that would move fluids back into the capillaries.
  22. A.  The hemolymph that circulates through the system is the same fluid that bathes the tissues.
  23. B.  Leukocytes don’t participate in clotting of blood.
  24. E.  Among the many things that hemoglobin does is the transport of CO2.
  25. D.  Hemoglobin has a lower affinity for O2 in acidic conditions (the Bohr shift), and thus releases O2 in tissues with a slightly lowered pH due to the presence of carbonic acid.
  26. E.  The residual volume is the volume of air that remains in the lungs after complete exhalation.
  27. A.  The H+ from carbonic acid lowers the pH of cerebrospinal fluid, which stimulates the breathing centers to increase respiration rates.
  28. A.  Antigen is a contraction of antibody-generator.
  29. D.  Antibodies bind to invaders in the body fluids (this is humoral immunity).  Question from the text website.
  30. B.  The release of perforin by Tc cells destroys infected cells. 
  31. A.  MHC molecules mark your cells as your own. 
  32. A.  The secretion of IL-1 by an APC that contains a foreign antigen is one of the signals that turns on Th cells.
  33. D.  Memory cells are primed to secrete antibodies against an invader that tries to reinvade at a later time.
  34. D.  The release of histamine is one of the first signals, and leads to many of the other events listed.
  35. E.  HIV attaches to CD4 positive cells (T helper cells) and as the number of Th cells declines, so does the IL-2 that they secrete to activate other cells of the immune system.
  36. B.  See figure 44.8
  37.  C.  The other answers either are not true, or have exceptions that invalidate those answers.
  38. A.  Conduction is the movement of heat from a body to another material in direct contact (such as water).
  39. C.  Nonshivering thermogenesis is the hormone-regulated production of heat from mitochondria in which the electron transport system has been short-circuited from producing ATP.  This often happens in brown fat. 
  40. B.  The amino groups of amino acids in proteins are the source of nitrogenous waste.
  41. C.  The only selectivity in filtration is based on the size of molecules.
  42. C.  Alcohol interferes with the production of antidiuretic hormone. 
  43. D.  The filtrate becomes very dilute due to loss of NaCl in the ascending limb of the loop of Henle.
  44. C.  Water passively crosses the epithelium at all these points.
  45. D.  NaCl leaves the tubule at V and VII, and urea leaves the tubule at VII.  These solutes remain in the kidney and contribute to the high osmolarity that draws water from the tubule.