40. Which of these statements about gamma interferon is false?
(A) It stimulates the immune system to attack infected cells and tumors.
(B) It is produced by almost all cells of the body.
(C) It is a polypeptide regulator.
(D) It can be produced in response to viral infections.

36. In vertebrate animals, spermatogenesis and oogenesis differ, in that (A) oogenesis begins at the onset of sexual maturity, whereas spermatogenesis happens in embryonic development. (B) oogenesis produces four haploid cells, whereas spermatogenesis produces only one functional spermatozoon. (C) cytokinesis is unequal in oogenesis, whereas it is equal in spermatogenesis. (D) spermatogenesis is not completed until after fertilization occurs, but oogenesis is completed by the time a girl is born.

37. Biologists have discovered how to put together a bacteriophage with the protein coat of phage T2 and the DNA of phage lambda. If this composite phage was allowed to infect a bacterium, the phages produced in the host cell would have (A) a mixture of the DNA and proteins of both phages. (B) the protein and DNA of phage lambda. (C) the protein of phage T2 and the DNA of phage lambda. (D) the protein of phage lambda and the DNA of phage T2.

38. Which of the following hormones have antagonistic (opposing) effects? (A) growth hormone and epinephrine (B) glucagon and thyroxine (C) ACTH and cortisone (D) parathyroid hormone and calcitonin

39. Which of these statements about edema is false? (A) Edema may be caused by blockage of lymphatic vessels. (B) Edema may be caused by high blood pressure. (C) Edema may be caused by increased plasma protein. (D) Edema may be caused by leakage of plasma protein into tissue fluid.

41. Which of these statements about intrinsic factor is false? (A) It helps prevent pernicious anemia. (B) It is secreted by the pancreas. (C) It promotes absorption of vitamin B12 in the intestine. (D) It is a polypeptide.

42. Which of the following would tend to reduce the concentration of lactic acid that accumulates in a muscle cell as a result of contractile activity? (A) increasing the diameter of the cell (B) increasing the number of mitochondria in the cell (C) decreasing the oxygen supply to the cell (D) increasing the concentration of glycolytic enzymes. 

43. Which of these statements about fat digestion and absorption is false? (A) Triglycerides are resynthesized from monoglycerides and fatty acids in the intestinal epithelial cells. (B) Triglycerides are hydrolyzed by the action of pancreatic lipase. (C) Triglycerides, as particles called chylomicrons, are absorbed into blood capillaries within the villi. (D) Emulsification by bile salts increases the rate of fat digestion.

44. Moment-to-moment changes in total peripheral resistance are normally due to changes in (A) the viscosity of blood. (B) the radius of certain blood vessels in the systemic circuit. (C) the lengths of blood vessels in the systemic circuit. (D) the cardiac output.

45. The motor end plate is (A) the specialized region of an effector organ innervated by an autonomic postganglionic neuron. (B) the specialized synaptic terminal of autonomic postganglionic neurons. (C) the specialized synaptic terminal of the motor neuron. (D) the specialized region of skeletal muscle innervated by a motor neuron.

46. Which of the following is most likely to cause a decrease in the stroke volume of the left ventricle? (A) an increase in end-diastolic volume (B) an increase in the activity of sympathetic nerves to the heart (C) an increase in mean arterial pressure (D) an increase in end-diastolic pressure