Bio 105 Final (Master)

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32. A male silkworm moth locates a female at a distance by a. flying toward a chemical signal. b. flying toward a sound signal. c. flying toward anything shaped like a female moth. d. emitting a sound as the female approaches. e. emitting a chemical as the female approaches.

57. Pepsinogen is converted into pepsin by a. low pH. b. chyme. c. enterokinase. d. trypsinogen. e. amylase from the salivary glands.

73. Blockage of a coronary artery can cause a. a heart attack. b. a stroke. c. fainting. d. edema. e. anemia.

13. Which muscle type contains intercalated disks? a. Smooth b. Cardiac c. Skeletal d. Both a and b e. All of the above

39. Which of the following teeth are most prominent in mammalian carnivores? a. Incisors b. Canines c. Premolars d. Molars e. Cheek teeth

6. Which of the following are not types of glial cells? a. Oligodendrocytes b. Bipolar cells c. Schwann cells d. Astrocytes e. Microglia

21. The _______ acid in gastric juice is lethal to many pathogens. a. sulfuric b. carbolic c. hydrochloric d. formic e. protease

24. In a neuron at rest, the resting membrane potential is mainly due to a. the number of voltage-gated channels in the membrane. b. the difference in the concentration of Na+ inside and outside of the cell. c. passive leak currents in the cell membrane. d. the active transport of K+ ions out of the cell. e. the electrical charge in the extracellular fluid.

24. Which of the following diseases differs from the others in terms of the kind of deficiency that causes it? a. Pellagra b. Rickets c. Goiter d. Pernicious anemia e. Beriberi

72. The first hormone ever discovered was a. testosterone. b. gastrin. c. secretin. d. gluconeogenase. e. glucagon.

41. Blood enters the glomerulus by way of the a. peritubular capillaries. b. vasa recta. c. efferent arteriole. d. afferent arteriole. e. renal vein.

70. Which of the following is the true stomach of a ruminant? a. Cecum b. Reticulum c. Rumen d. Omasum e. Abomasum

73. The cells targeted by HIV are a. neurons. b. platelets. c. erythrocytes. d. mast cells. e. T-helper cells.

46. The most abundant cells in the blood are a. erythrocytes. b. leukocytes. c. phagocytes. d. platelets. e. None of the above

47. In which of the following PO2 environments would hemoglobin release its O2 most easily? a. 30 mm Hg b. 50 mm Hg c. 70 mm Hg d. 90 mm Hg e. 110 mm Hg

49. When an action potential arrives at an axon terminal, it causes the opening of _______ channels, which triggers fusion of neurotransmitter vesicles with the cell membrane. a. calcium b. sodium c. potassium d. chloride e. acetylcholine

54. Which of the following is not caused by the HCl secreted in the stomach? a. Formation of chylomicrons b. Proper pH for the digestive enzyme of the stomach c. Breakdown of ingested tissues d. Activation of the principal zymogen of the stomach e. Death of ingested bacteria

63. Which of the following proteases is produced by the small intestine? a. Dipeptidase b. Chymotrypsin c. Trypsin d. Carboxypeptidase e. Pepsin

69. When you read this question and your nervous system sends the information from your eyes to your brain, the information is carried by a. afferent neurons. b. efferent neurons. c. nodes. d. glial cells. e. None of the above

85. Which of the following would most likely cause a decrease in ADH (vasopressin) secretion? a. A rise in blood pressure b. A significant loss of blood c. An energetic, sweaty workout d. Hiking in the desert e. Decreased activity in baroreceptors of the large arteries

92. Which type of joint allows for almost complete rotational movement? a. Ball-and-socket b. Pivot c. Hinge d. Saddle e. Plane

13. Aquatic _______ are in a double bind, because their demand for oxygen increases as the temperature of their environment increases, but the oxygen content of water declines with increasing water temperatures. a. insects b. ectotherms c. endotherms d. plants e. None of the above

23. The nutritional deficiency disease rickets is caused by an inadequate supply of the fat-soluble vitamin a. A (retinol). b. D (calciferol). c. E (tocopherol). d. K (menadione). e. biotin.

40. Meissner's corpuscles a. adapt very slowly to pressure. b. sense changes in light touch. c. sense deep pressure. d. have concentric layers of connective tissue. e. are present uniformly on skin surfaces.

76. A high _______ will lead to an autoregulatory increase of blood flow to a tissue. a. blood pressure b. CO2 concentration c. O2 concentration d. ATP concentration e. glucose concentration

89. The human elbow consists of a _______ joint. a. ball-and-socket b. pivot c. hinge d. saddle e. plane

17. The cell type that differentiates into a sperm cell at the end of spermatogenesis a. Sperm b. Spermatogonia c. Spermatids d. Primary spermatocytes e. Secondary spermatocytes

21. During oogenesis, the first haploid cell with abundant cytoplasm that is produced is the a. second polar body. b. primary oocyte. c. secondary oocyte. d. first polar body. e. ootid.

23. Which of the following vertebrates has a three-chambered heart with both pulmonary and systemic circuits? a. Fish b. Lungfish c. Amphibian d. Crocodilian e. Both b and c

29. Which of the following is most likely responsible for fever during inflammation? a. Fibrinogen b. Complement proteins c. Cytokines d. Class I MHC proteins e. Class II MHC proteins

38. The root of a typical tooth contains _______ and _______, but not _______. a. enamel; cement; a pulp cavity b. enamel; a pulp cavity; dentine c. dentine; a pulp cavity; enamel d. dentine; enamel; a pulp cavity e. cement; dentine; a pulp cavity

4. Unlike humans, kangaroos can increase their speed of movement without an increase in their metabolic rate because a. their diet is more energy-rich than ours is. b. they have more mitochondria per cell than we do. c. the recoil in their elastic tendons helps power each jump. d. they convert starch directly to ATP without first hydrolyzing it to glucose. e. they alternate which foot they use each time they jump.

59. The diameter of a capillary is about the same as that of a(n) a. arteriole. b. nerve. c. red blood cell. d. valve. e. venule.

74. An intrauterine device is a means of birth control that prevents a. ovulation. b. fertilization. c. implantation. d. ejaculation. e. sperm from reaching the egg.

21. Vertebrate skeletal muscles are categorized as excitable cells because they a. can be stimulated by ATP. b. can be stimulated by an electric charge. c. can secrete neurotransmitter. d. possess voltage-gated sodium channels. e. can attain a high level of activity.

44. The simplest immunoglobulins have _______ polypeptide chain(s). a. one b. two c. three d. four e. None of the above

48. Hair cells are not associated with which of the following structures? a. Vestibular system b. Organ of Corti c. Cochlea d. Muscle spindle e. Semicircular canal

55. Functions as a countercurrent multiplier a. Renal pyramid b. Proximal convoluted tubule c. Distal convoluted tubule d. Loop of Henle e. Collecting duct

56. Monoclonal antibodies have been used for all of the following except for a. immunoassays. b. immunotherapy. c. treating some forms of breast cancer. d. increasing the immune response for a tissue transplant. e. pregnancy tests.

6. Gas exchange in animals always involves a. lungs. b. breathing movements. c. neural control. d. diffusion between internal body fluids and the outside medium. e. active transport of gases.

68. Chemoreceptors on the surface of the medulla are sensitive to a. O2. b. N2. c. surfactant. d. CO2 and the pH of the cerebrospinal fluid. e. None of the above

77. Which of the following brain areas integrates sensory and motor information? a. Brain stem b. Olfactory lobe c. Cerebrum d. Cerebellum e. None of the above

13. Which of the following is not a leukocyte? a. Macrophage b. T lymphocyte c. Basophil d. Mast cell e. Red blood cell

23. An experimental procedure that temporarily immobilizes cilia of flame cells in flatworms would impair which of the following? a. Filtration b. Reabsorption c. Secretion d. Both b and c e. All of the above

35. Organisms living in the lightless interiors of caves often rely on ingesting dead organic matter that washes in from the surface. They can therefore be described as a. predators. b. omnivores. c. carnivores. d. herbivores. e. detritivores.

4. In an active synapse composed of a presynaptic and postsynaptic cell, which part of the presynaptic cell is the last to participate in the action potential? a. Axon b. Axon hillock c. Dendrites d. Cell body e. Axon terminals

42. Which of the following receptors are located deep in the skin and are adapted specifically for sensing pressure? a. Meissner's corpuscles b. Free nerve endings c. Tactile receptors d. Sweat glands e. Pacinian corpuscles

46. When the stereocilia of hair cells are bent, the membranes of the hair cells a. are depolarized. b. are hyperpolarized. c. generate action potentials. d. contract the stereocilia. e. Either a or b

52. The lifetime of an individual red blood cell is approximately a. 4 hours. b. 4 days. c. 4 weeks. d. 40 days. e. 4 months.

6. An individual sarcomere unit consists primarily of a. a stack of actin fibers. b. a stack of myosin units. c. overlapping actin and membrane. d. overlapping myosin and membrane. e. overlapping actin and myosin.

63. Carbonic anhydrase is an enzyme in red blood cells that catalyzes a reaction between CO2 and a. HCO3-. b. H2CO3. c. hemoglobin. d. O2. e. water.

67. The major function of the colon, or large intestine, is the a. digestive breakdown of foods. b. absorption of nutrients from foods. c. housing of parasitic bacteria. d. secretion of bile and enzymes. e. reabsorption of ions and water.

70. Increases in circulating levels of antidiuretic hormone (ADH) would not cause an increase in which of the following? a. The number of aquaporins in cells of the collecting ducts b. Blood volume c. The permeability of the collecting ducts d. Blood pressure e. Blood osmolarity

74. HIV can be transmitted from person to person in a. blood. b. semen. c. vaginal fluid. d. breast milk. e. All of the above

75. The hormone secretin is a chemical message a. secreted by the pancreas. b. secreted by the stomach. c. whose release is stimulated by the nervous system. d. that triggers the intestine to release enzymes. e. that triggers pancreatic secretion.

8. In an open circulatory system, a. there is no heart. b. there is a gastrovascular cavity. c. there are no blood vessels. d. hemolymph flows out of the body. e. there is no distinction between hemolymph and extracellular fluid.

80. When a person has an accident that results in a broken arm, a. they have injured their axial skeleton. b. membranous bone has been injured. c. the impact is on a part of the appendicular skeleton. d. cartilage bone has been broken. e. Both c and d

88. Human bodies have which of the following types of joints? a. Ball-and-socket b. Hinge c. Pivot d. Saddle and ellipsoid e. All of the above

18. A paleontologist finds a fragment of a fossilized vertebrate that indicates that the animal had a four-chambered heart arranged in a single circuit. The animal could have been a(n) a. fish. b. amphibian. c. crocodile. d. bird. e. Both c and d

24. The olfactory bulb is part of the a. brain. b. nasal epithelium. c. organ of Corti. d. cochlea. e. None of the above

27. Which of the following is a feature of cardiac muscle that helps the heart withstand high pressures without tearing? a. Branching and intertwined fibers b. Fibers arranged in parallel c. A single nucleus possessed by each fiber d. Gap junctions between fibers e. The pacemaking functions of some fibers

30. If you get a splinter in your hand, your body responds with a number of inflammation and wound-healing responses. Which of the following is not one of those responses? a. Histamines cause capillaries to constrict. b. Phagocytes engulf bacteria and other dead cells. c. Wound healing begins when signaling molecules stimulate cell division in the skin. d. Some cytokines elevate body temperature. e. Complement proteins attract phagocytes.

32. Prairie dogs feed on a variety of grasses and herbs, and black-footed ferrets feed almost exclusively on prairie dogs. Both of these animals can be described as a. predators. b. saprobes. c. carnivores. d. herbivores. e. autotrophs.

38. Each B cell can produce _______ kind(s) of antibodies. a. 1 b. 2 to 4 c. an average of 6 d. more than 20 e. None of the above; B cells do not produce antibodies.

47. Which structure of the vertebrate gut is a membrane covering the abdominal organs? a. Peritoneum b. Mucosal layer c. Submucosal layer d. Circular muscle layer e. Longitudinal muscle layer

57. Mifepristone (formerly called RU-486) terminates a pregnancy by blocking the action of progesterone. The termination occurs because progesterone is needed to a. maintain the endometrium. b. trigger ovulation. c. prompt formation of the corpus luteum. d. promote ovarian development. e. prompt degeneration of the corpus luteum

75. Color blindness is the result of a a. dysfunction of cone cells. b. deficiency in rhodopsin. c. mutation that affects the ganglion cell layer. d. deficiency of cone cells. e. mutation that affects the pigmented epithelium.

75. Nodes that are sensitive to O2 and blood pressure levels are located in the a. aorta and carotid arteries. b. brain stem capillaries. c. hypothalamus. d. pulmonary artery. e. pulmonary vein.

77. Which of the following statements is true? a. Opportunistic infections as a result of HIV infection are the usual cause of AIDS deaths. b. HIV causes death directly. c. AIDS typically arises within days of an HIV infection. d. HIV viral load rises steadily from the initial infection. e. AIDS is untreatable.

82. Which of the following is most likely to facilitate a parasympathetic response? a. A relaxing massage b. A significant loss of blood c. An energetic workout d. Watching a scary movie e. A drug that blocks the action of acetylcholine

14. Which of the following are not phagocytes? a. Dendritic cells b. T cells c. Basophils d. Macrophages e. Eosinophils

14. Which of the following groups of animals would be most suitable for a study of ammonia excretion? a. Cartilaginous fishes b. Bony fishes c. Mammals d. Birds e. Insects

21. A person experiencing the first symptoms of gout usually develops inflammation in joints of the extremities rather than in joints closer to the body core because a. urea is more soluble at lower temperatures. b. uric acid is less soluble at lower temperatures. c. urea is more rapidly converted to uric acid at lower temperatures. d. uric acid is more soluble at lower temperatures. e. ammonia is less soluble at lower temperatures.

26. Supplementation with _______ helps prevent the nutritional deficiency disease called goiter. a. fluoride b. iodine c. chromium d. zinc e. copper

31. As a male silkworm moth nears a female that is releasing the pheromone bombykol, a. the female starts to release more bombykol. b. the frequency of action potentials in his antennal nerve increases. c. he switches from pheromone detection to sight for locating the female. d. a larger number of the bombykol-sensitive hairs undergo adaptation. e. the receptor potential in bombykol-sensitive hairs is reduced.

31. Which of the following is not one of the key traits of the adaptive immunity response? a. The ability to respond specifically to a wide diversity of foreign molecules and organisms b. An extremely rapid response time c. Immunological memory that often is long-lasting. d. The ability to recognize "self" from "nonself" e. The ability to produce antibodies specific for antigenic determinants

43. The timing of the spread of the action potential from atrium to ventricle is controlled by the a. sinoatrial node. b. atrioventricular node. c. Purkinje fibers. d. bundle of His. e. ventricular mass.

47. When whole blood is centrifuged, it is separated into a liquid component called _______ and a bottom layer of _______. a. hematocrit; cells b. plasma; cells c. plaque; cells d. hematocrit; plasma e. packed cell volume; plasma

49. Which of the following statements about O2-binding curves is false? a. In normal metabolism, our body uses only the upper one-fourth of its oxygen-binding curve. b. A smaller decrease in PO2 is needed for hemoglobin to drop from 100 to 75 percent saturation than for hemoglobin to drop from 75 to 50 percent saturation. c. Our blood normally carries an enormous reserve of O2. d. The steepest part of the O2-binding curve results in a great release of O2 for only a modest drop in PO2. e. The PO2 of our blood drops below about 40 mm Hg only during extreme exertion.

67. When a clown at a birthday party squeezes a long balloon to twist it into a poodle or a hat, the volume of air inside the balloon stretches the balloon and extends its length and stays constant. This example is analogous to the action of muscles on the a. endoskeleton. b. hydrostatic skeleton. c. spandril skeleton. d. exoskeleton. e. tendril skeleton.

73. The activation of a rhodopsin molecule sets off a chain reaction that leads to the a. opening of a sodium channel. b. closing of a large number of sodium channels. c. formation of an activated phosphodiesterase molecule. d. activation of a large number of transducin molecules. e. activation of other rhodopsin molecules.

19. Which of the following organisms does not require both ventilation of its respiratory surfaces with a medium containing O2 and perfusion of its respiratory surfaces with blood? a. Crayfish b. Rabbit c. Insect d. Squid e. Bird

27. Which of the following statements about metanephridia is false? a. Urine flows out the nephridiopore. b. Blood is filtered as it passes through capillary walls into the coelom. c. One metanephridium occurs in each segment of an earthworm. d. Reabsorption and secretion occur in the metanephridium. e. The nephrostome is a ciliated opening to the metanephridium.

27. Which of the following statements about natural killer cells is false? a. They are a class of lymphocytes. b. They can distinguish between normal cells and cells that have been infected by viruses. c. They release antibodies. d. They initiate apoptosis of targeted cells. e. They can recognize some tumor cells and cause them to undergo cell death.

28. Which of the following statements about blocks to polyspermy in sea urchins is false? a. The slow block creates a physical barrier that sperm cannot penetrate. b. Blocks to polyspermy prevent more than one sperm from entering an egg. c. The fast block causes release of the acrosomal enzymes. d. The fast block results from a change in the electrical-charge difference across the plasma membrane of the egg. e. The slow block results from the release of calcium.

3. Which of the following statements about innate and adaptive defenses is false? a. Defense systems involve recognition of self from nonself. b. Innate defenses typically act more rapidly than adaptive defenses. c. Adaptive defense mechanisms are typically the body's first line of defense. d. The skin is an example of an innate defense. e. Innate defenses are called nonspecific defenses.

34. Which of the following statements about skeletal muscle contraction is false? a. A single action potential at the neuromuscular junction is sufficient to cause a muscle to twitch. b. An action potential in the muscle cell activates contraction by releasing Ca2+ into the sarcoplasm. c. Twitches are able to sum when Ca2+ is quickly removed from the sarcoplasm between action potentials. d. Summation of twitches leads to a graded increase in the tension that can be generated by a single muscle fiber. e. The tension generated by a muscle can be varied by controlling how many of its motor units are active.

34. Which of the following statements about the humoral immune response is true? a. It is directed against antigens that have become established within a cell. b. It is carried out by T cells. c. It involves soluble antibodies. d. All of the above e. None of the above

4. At sea level, atmospheric pressure is about _______ mm mercury. a. 1 b. 454 c. 760 d. 940 e. 1,000

42. If the thoracic wall is punctured, air leaking in will cause the lung to collapse. Thus in the normal, intact thoracic cavity, a. lung expansion is passive. b. air pressure is the same as it is on the outside. c. a slight negative pressure keeps the alveoli partly inflated. d. breathing movements keep lungs inflated. e. Both a and b

47. In the human blood, the most abundant antibody class is a. IgE. b. IgM. c. IgG. d. cytokine. e. monoclonal.

47. The primary determinant regarding the proportion of fast- and slow-twitch fibers in skeletal muscle is a. diet. b. exercise. c. genetic heritage. d. age. e. None of the above

47. Which of the following statements concerning the nodes of Ranvier is true? a. The myelinated membrane adjacent to the nodes allows the firing of action potentials. b. The nodes are regions where the nerve axon is myelinated. c. Action potentials jump from node to node. d. Voltage-gated ion channels are clustered in the regions between the nodes. e. Positive current flows along the outside of the myelinated axon in between the nodes.

5. The striated appearance of skeletal muscle is due to the a. dark color of myosin. b. multiple nuclei per fiber. c. regular arrangement of filaments relative to each other. d. dense array of microtubules. e. dense packing of ATP molecules.

53. Which of the following statements about the function of blood is false? a. It transports O2 and CO2. b. It transports body heat to where it is most needed. c. It produces red blood cells. d. It acts as a buffer to changes in pH. e. It transports nutrients to cells.

6. B cells mature in a. the thymus. b. lymph nodes. c. bone marrow. d. the spleen. e. circulating blood.

75. An advantage of an endoskeleton over an exoskeleton is that an endoskeleton a. provides muscle attachment sites. b. provides protection. c. grows as the animal grows. d. supports the animal's weight. e. gives structure to the animal.

11. Which muscle type has gap junctions? a. Smooth b. Cardiac c. Skeletal d. Both a and b e. All of the above

14. Cells that are produced from mitotic divisions of spermatogonia but are no longer mitotic themselves a. Sperm b. Spermatogonia c. Spermatids d. Primary spermatocytes e. Secondary spermatocytes

16. Which of the following represents the correct ranking of the water solubility of nitrogenous wastes, from least to most soluble? a. Ammonia, urea, uric acid b. Urea, uric acid, ammonia c. Uric acid, ammonia, urea d. Uric acid, urea, ammonia e. Ammonia, uric acid, urea

29. Oxygenated blood is carried by the a. aorta. b. pulmonary vein. c. pulmonary artery. d. Both a and b e. Both a and c

35. Lymphocytes specific for certain antigens proliferate by a process known as a. effector selection. b. clonal anergy. c. class switching. d. clonal selection. e. monoclonal formation.

41. If the seminal vesicles in a human male are defective, a. the man makes functional sperm but is unable to ejaculate. b. the man's sperm lack functional flagella. c. the fluid needed to lubricate the man's urethra for easier sperm travel is defective. d. the man's semen lacks the fructose fuel needed for the sperm to swim. e. the man's Leydig cells do not make testosterone needed to stimulate spermatogenesis.

48. Which of the following does not play a role in renal filtration? a. Walls of glomerular capillaries b. Podocytes c. Basal lamina of glomerular capillaries d. Collecting ducts e. Bowman's capsule

54. Connects the proximal and distal convoluted tubules a. Renal pyramid b. Proximal convoluted tubule c. Distal convoluted tubule d. Loop of Henle e. Collecting duct

61. Bile aids in the breakdown of lipids by a. hydrolyzing lipids. b. activating hydrolytic enzymes. c. aggregating droplets of lipids. d. emulsifying lipids. e. making lipids water soluble.

62. Metabotropic receptors differ from ionotropic receptors in that metabotropic receptors a. are not ion channels. b. initiate responses that generally are slower and longer lasting. c. are not transmembrane proteins. d. Both a and b e. All of the above

64. The blood vessels with the greatest capacity to store blood are the a. arteries. b. arterioles. c. capillaries. d. veins. e. venules.

66. Below the level of the heart, the movement of blood in the veins toward the heart is caused primarily by a. gravity. b. the contraction of venous walls. c. cilia lining the veins. d. the contraction of nearby skeletal muscles. e. venous capacitance.

66. Which of the following is not necessary for the formation of a neural network? a. Neurons carrying sensory information into the nervous system b. Neurons carrying commands to effector structures such as muscles and glands c. Neurons integrating information between incoming sensory neurons and outgoing efferent neurons d. A brain that coordinates information between afferent and efferent neurons e. Synapses between presynaptic and postsynaptic neurons

73. A vasectomy is a relatively minor operation in which the _______ is (are) cut and the loose ends are tied off. a. epididymis b. urethra c. oviduct d. vas deferens e. seminiferous tubules

76. Which of the following contraceptive methods has a success rate greater than 95 percent? a. Spermicidal jelly b. Condom c. Diaphragm d. Oral hormones ("the pill") e. Cervical cap

11. The various diseases that attack glial cells a. include multiple sclerosis. b. may be caused by an autoimmune disorder. c. can impair one's ability to move. d. may cause demyelination of nerves. e. All of the above

13. If the metabotropic receptors in photoreceptors are pharmacologically blocked, the exposure of these photoreceptors to light will a. raise the intracellular concentration of cations. b. lower the intracellular concentration of cations. c. cause electroreceptors to open ion channels. d. cause ionotropic receptors to allow cation flow. e. have no effect on these receptors.

2. An elephant uses its trunk a. to pluck leaves from trees. b. to pull plants from the ground. c. to obtain water to squirt in its mouth. d. as a snorkel. e. All of the above

30. _______ chemically binds with calcium and acts as a second messenger in smooth muscle cells. a. Myosin b. Actin c. Troponin d. Cyclic AMP e. Calmodulin

33. Insect flight muscles can contract up to _______ times per second. a. 5 b. 50 c. 100 d. 500 e. 1,000

38. If a new air pollutant were to destroy the surfactant in people's lungs, one likely result would be a. increased surface tension of the fluid lining their alveoli. b. increased uptake of CO2 from the environment. c. increased effort needed to breathe. d. decreased levels of hydrogen bonding in the fluid of their alveoli. e. Both a and c

60. In a human, about 180 liters of filtrate enter Bowman's capsule each day. Approximately how much of this fluid is typically returned to the blood? a. 2 liters b. 18 liters c. 40 liters d. 90 liters e. 178 liters

63. The amount of light entering the eye is decreased when the a. distance between the lens and retina is decreased. b. distance between the lens and retina is increased. c. iris relaxes. d. shape of the lens changes. e. iris constricts.

65. Performing a chin-up is usually the most difficult at the very end of the exercise because a. of the lever properties of the muscle-joint interaction. b. there is so much overlap between actin and myosin in the sarcomeres. c. of psychological fatigue that is a metabolic by-product of the exertion. d. of the necessary switch from fast- to slow-twitch fibers. e. Both a and b

71. Which of the following statements about the ganglia of invertebrates is true? a. They allow animals to perform simple, but not complex, behaviors. b. Paired ganglia are present primarily in radially symmetrical organisms. c. Paired ganglia are found in the nerve nets of cnidarians. d. They are found primarily in organisms with nerve nets. e. A large set of fused ganglia at the anterior end of an organism is a brain.

74. Which of the following statement about skeletons is true? a. No skeleton consists entirely of cartilage. b. Hydrostatic skeletons cannot perform the function of locomotion. c. An advantage of an exoskeleton is that it can continue to grow throughout the life of the animal. d. Unlike bones, external skeletons must remain flexible and therefore do not contain calcium carbonate crystals. e. There are two categories of bone: membranous bone and cartilage bone.

8. For every white blood cell in a given volume of human blood, there are about _______ red blood cells. a. 2 b. 10 c. 50 d. 100 e. 1,000

1. A frog can jump _______ times its body length, a human can jump _______ times his or her body length, and a flea can jump _______ times its body length. a. 20; 5; 200 b. 6.5; 7.4; 1.2 c. 5; 20; 200 d. 200; 5; 20 e. 7.4; 6.5; 1.2

1. Humans are unable to see the _______ region of the electromagnetic radiation spectrum. a. infrared b. red c. indigo d. violet e. black

1. The key problem faced by elephants when they are swimming is a. the difference between the pressure in their blood vessels and the air pressure at the water surface. b. water entering their cells and causing lysis. c. water leaving their cells in response to a concentration gradient. d. infection by pathogens. e. All of the above are equally serious.

11. A long period of dry, hot weather has caused evaporation of water, resulting in an increase in salt concentrations in the ponds inhabited by the brine shrimp Artemia. How will the shrimp respond physiologically? a. They will transport salt out of their extracellular fluids to the environment. b. They will move water across their gill membranes by means of active transport. c. They will maintain osmolarity of their extracellular fluids above environmental levels. d. They will osmoconform with their surroundings. e. They will transport salt from the environment to their extracellular fluids.

12. Which muscle type has the least regular arrangements of actin and myosin? a. Smooth b. Cardiac c. Skeletal d. Both a and b e. All of the above

12. Which of the following best represents the order of the flow of information from a muscle in a crayfish that will ultimately generate an action potential in the crayfish stretch receptor neuron? a. Stretch, ion channels open, receptor potential, voltage-gated Na+ channels open, action potential b. Stretch, dendritic potential, ion channels open, receptor potential, action potential c. Stretch, receptor potential, spread of potential in receptor neuron, neurotransmitter release, action potential d. Stretch, neurotransmitter release, receptor potential, ion channels open, action potential e. Stretch, ion channels open, neurotransmitter release, voltage-gated Na+ channels open, action potential

12. Which of the following is not a leukocyte? a. Platelet b. Neutrophil c. Dendritic cell d. Macrophage e. Mast cell

13. Which of the following statements about vitamin C is false? a. It is a fat-soluble vitamin. b. It is obtained from fresh greens and fruit in the diet. c. It is an essential vitamin for humans. d. It is necessary for wound healing. e. An excess of vitamin C is excreted.

14. Which of the following is not one of the responses of a fish to a drop in water temperature? a. Increased metabolic rate c. Decreased blood flow d. Decreased O2 consumption e. Decreased expenditure of energy for breathing e. None of the above

15. Cruise ship passengers find themselves fighting flu-like symptoms for the first 4-5 days of their trip, but eventually recover and enjoy their trip. Which of the following defenses is last to be involved in their recovery? a. Antibodies b. Lysozymes c. Mucus d. Their skin, as an example of an innate defense e. Phagocytosis

15. In the fish circulatory system, blood a. moves from the muscular ventricle to the bulbus arteriosus to the gills. b. enters the aorta under high pressure. c. leaves the heart and moves to body tissues. d. leaves the gills under high pressure. e. is received from the body into a muscular atrium.

15. Which of the following events does not occur during skeletal and cardiac muscle contraction? a. The distance between Z lines increases. b. The sarcomeres shorten. c. The H zone is reduced. d. The I band is reduced. e. The area of actin and myosin overlap increases.

16. Which of the following animals would be the best for illustrating the evolutionary transition of the vertebrate circulatory system from a single loop system to one with two separate pulmonary and systemic circuits? a. Lungfish b. Ancestral ray-finned fish c. Birds d. Amphibians e. Reptiles

17. Some prescription drugs have the side effect of interfering with the senses of taste and smell. One explanation for this side effect is that these drugs may a. bind to chemoreceptors in the nasal cavity and tongue. b. inactivate an electroreceptor. c. diminish the stretch response. d. chemically block a pressure-sensitive cation channel. e. increase the activity of thermoreceptors.

17. Which of the following statements about insect respiration is false? a. Spiracles are the air tubes that carry the respiratory gases. b. Because O2 diffuses more quickly in air than in water, the insect respiratory system is highly efficient. c. Air capillaries are close to every mitochondrion in an insect's flight muscles. d. Some larval insects have external gills. e. The insect tracheal system brings air to all tissues in the body.

18. Which of the following represents the correct ranking of the amount of nitrogenous wastes in a molecule, from least to most nitrogen? a. Ammonia, urea, uric acid b. Urea, uric acid, ammonia c. Uric acid, ammonia, urea d. Uric acid, urea, ammonia e. Ammonia, uric acid, urea

19. Which of the following statements about the interaction between actin and myosin molecules is true? a. Globular myosin heads bind to actin filaments. b. Globular actin heads bind to myosin filaments. c. They are connected by other proteins. d. Myosin filaments bend to connect to actin. e. Actin filaments bend to connect to myosin.

20. Antibodies produced by the human immune system are typically prevented from getting to the brain by the blood‒brain barrier. Does this mean that the brain has no immune defenses? a. No, microglia in the brain and spinal cord provide an immune function. b. No, astrocytes carry out an immune function in addition to their other functions. c. No, macrophages from the general circulation cross the blood‒brain barrier. d. Yes, but there is no need for immune defenses in the central nervous system since the blood‒brain barrier also protects it from infection. e. Yes, this is why an infection in the brain is so dangerous.

20. Metabolism of carbohydrates and fats produces a. water and carbon dioxide. b. water and nitrogenous wastes. c. carbon dioxide and nitrogenous wastes. d. ammonia. e. water and ammonia.

21. Which of the following statements about microglia is true? a. They mediate inflammatory responses in the brain and spinal cord. b. They act as macrophages in the peripheral nervous system. c. They form synapses with brain neurons and conduct action potentials. d. They form myelin sheaths around neurons of the peripheral nervous system. e. They supply neurons of the brain and spinal cord with nutrients.

22. Consider the following statement: "Voltage is to the flow of electrically charged particles as pressure is to the flow of water." This statement indicates that voltage is the a. force that moves charged particles. b. rate at which charged particles move. c. resistance against moving charged particles. d. number of charged particles moving between two points e. conduction of charged particles along a pathway.

22. Which of the following defenses is most likely to be provided by complement proteins? a. Lysing of invading cells b. Deactivation of the inflammation response c. Insertion of nitric oxide into microbes d. Production of interferons e. Promotion of genetic recombination

22. While examining histological sections derived from the ovaries of human females at various life stages, you come across a slide labeled "section of an ovary from a mature female." You would expect to find all of the following cells on the slide except for a. a second polar body. b. an arrested primary oocyte. c. a secondary oocyte. d. a first polar body. e. a primary oocyte resuming meiosis.

23. The delicate gills of fishes are supported by _______ and _______. a. opercular flaps; gill arches b. opercular flaps; gill filaments c. gill filaments; gill arches d. opercular flaps; a diaphragm e. gill arches; a diaphragm

23. What is the role of the sarcoplasmic reticulum in muscle contraction? a. It stores Ca2+ ions for release during contraction. b. It surrounds and protects the muscle filaments. c. It provides sites of ATP synthesis. d. It depolarizes when stimulated by an impulse. e. It synthesizes actin and myosin filaments.

23. Which of the following statements about interferons is false? a. They signal neighboring cells to secrete antibodies. b. They are signaling molecules produced by cells infected with a pathogen. c. They are a type of cytokine. d. They are produced in response to viral infections. e. They are part of the innate immune response.

24. When submerged, frogs receive most of their O2 from capillaries within their skin. Which of the following structures is likely to contain blood with the highest O2 concentration in a submerged frog that is not able to breathe using its lungs? a. Right atrium b. Left atrium c. Aorta d. Ventricle e. Pulmonary vein

25. Which of the following does not represent a correct pairing of an animal with a component of its excretory system? a. Flatworm‒nephridiopore b. Insect‒Malpighian tubules c. Earthworm‒metanephridium d. Flatworm‒protonephridium e. Earthworm‒nephrostome

25. While examining histological sections derived from the testes of human males at various life stages, you come across a slide from the prenatal period. Which of the following would you see on this slide? a. Spermatogonia b. Spermatogonia and primary spermatocytes c. Secondary spermatocytes d. Spermatids e. Sperm

26. Which of the following statements about olfaction is false? a. In general, mammals depend less on olfaction than on vision as their dominant sensory modality. b. Olfactory stimuli are recognized by the interaction between odorant molecules and receptor proteins on olfactory cilia. c. The more odorant molecules that bind to receptors, the more action potentials that are generated. d. The greater the number of action potentials generated by an olfactory receptor, the greater the intensity of the perceived smell. e. The perception of different smells results from the activation of different combinations of olfactory receptors.

27. You observe two species of amphibians mating in a stream. Species A is engaging in external fertilization and Species B is engaging in internal fertilization. In which species would recognition molecules on gametes be more critical? a. Species A b. Species B c. Recognition molecules would be equally critical in both species A and species B. d. Neither, because vertebrates do not need recognition molecules on their gametes. e. There is insufficient information to make a determination.

28. In which of the following groups of organisms is excretion closely associated with the digestive system? a. Insects b. Flatworms c. Annelids d. Both a and b e. Both b and c

28. The nutritional deficiency disease beriberi is caused by an inadequate supply of the water-soluble vitamin a. B1 (thiamin). b. B2 (riboflavin). c. B12 (cobalamin). d. folic acid. e. C (ascorbic acid).

28. Which of the following cells release histamines when tissues are damaged? a. Mast cells b. B lymphocytes c. Macrophages d. Monocytes e. Phagocytes

29. As a male silkworm moth nears a female that is releasing pheromone, a. he can find the female by following a concentration gradient of the pheromone. b. the action potentials in his antennal nerve decrease. c. fewer pheromone-sensitive hairs are stimulated per second. d. the female starts to release more pheromone. e. he switches from pheromone detection to sight for locating the female.

29. Which of the following statements about an excretory system consisting of Malpighian tubules is false? a. As ions move into the tubules, water moves out. b. Uric acid is excreted from the rectum. c. There is active transport of ions and uric acid into excretory system. d. There is active transport of ions from hindgut back to extracellular fluid. e. They are found in insects.

3. Budding and regeneration share which of the following characteristics? a. Both can lead to the production of a new individual through mitotic growth. b. Both use meiosis to replace lost tissue. c. Both can lead to the production of a new individual through meiotic growth. d. Both serve as a trigger for the sexual phase of reproduction. e. Both are restricted to simple multicellular animals.

3. Numerous organisms in the deep-sea thermal vents, far below the surface and away from any light, survive by harvesting chemical energy stored in the bonds of inorganic molecules rising from the interior of Earth. These organisms can therefore be described as a. autotrophs. b. heterotrophs. c. carnivores. d. herbivores. e. predators.

3. Some relatively large multicellular aquatic animals that are many cell-layers thick have no circulatory system. One way in which these organisms manage gas exchange is a. by bringing the external environment into a branched system of channels such that most cells are close to that environment. b. by means of endosymbiotic bacteria that produce oxygen inside their tissues. c. by breathing air into a set of lungs. d. by basking at the surface periodically to allow for diffusion of oxygen. e. None of the above

3. Which of the following represents the correct order of the parts of neurons that are involved in the flow of information, beginning with the presynaptic cell and ending where a synapse is made with a postsynaptic cell? a. Dendrites, cell body, axon hillock, axon, axon terminals b. Cell body, axon terminals, axon hillock, axon, dendrites c. Axon, cell body, dendrites d. Axon terminals, axon hillock, cell body, dendrites e. Synapse, axon, cell body, dendrites

31. Which of the following is the most likely advantage of hermaphroditism? a. For a given species, every organism is a potential mate. b. As compared to reproduction in dioecious species, simpler behavior patterns are required for mate selection. c. More rapid reproduction of genetically successful individuals is possible through asexual reproduction as compared to sexual reproduction. d. Complex hormonal control and feedback mechanisms are not required for reproduction. e. Complex primary sex organs are not required.

31. Which of the following structures is the site of gas exchange in the lungs? a. Alveoli b. Bronchi c. Bronchioles d. Trachea e. Both a and b

33. If vertebrates evolved in freshwater, then the primary function of the earliest vertebrate nephron was probably to a. remove excess water. b. remove excess salts. c. remove excess nutrients. d. conserve nutrients. e. conserve water.

33. In humans, the lower (posterior) side of the thoracic cavity is formed by the a. diaphragm. b. esophagus. c. stomach. d. ribs. e. intercostal muscles.

33. The left ventricle in humans is more muscular than the right ventricle because a. resistance is higher in the systemic circuit. b. resistance is higher in the pulmonary circuit. c. the left ventricle pumps more total blood. d. the left ventricle pumps more viscous blood. e. the lymphatic system empties into the left ventricle.

35. A blood pressure reading from a sphygmomanometer is measured in millimeters of mercury. For a reading of 140/100, for example, the first number represents _______ and the second number represents _______. a. pressure during ventricular contraction; pressure during ventricular relaxation b. pressure during ventricular relaxation; pressure during ventricular contraction c. pressure during ventricular contraction; pressure during atrial contraction d. pressure during atrial contraction; pressure during ventricular contraction e. diastolic pressure; systolic pressure

35. A simultaneous hermaphrodite a. has primary sex organs of both sexes at the same time. b. functions as a male at one time in its life and as a female at another. c. develops from unfertilized eggs. d. usually self-fertilizes. e. has gonads that alternate between being ovaries and testes.

36. Which of the following statements about voltage-gated channels is true? a. They open or close in response to a change in voltage across the cell membrane. b. They all open and close at the same time in response to an action potential. c. Ions can move through the channels only if the overall membrane potential stays the same. d. Ions are pumped through the channels in order to maintain the existing membrane potential. e. They open only in response to an action potential.

39. A scientist wishing to study how animals produce urine that is more concentrated than their body fluids should choose a study species from which of the following groups? a. Mammals b. Marine bony fishes c. Crocodiles d. Frogs e. Cartilaginous fishes

4. Marine invertebrates in which the osmolarity of the extracellular fluids equilibrates with the environment are known as a. osmoconformers. b. osmoregulators. c. ionic regulators. d. hypotonic. e. hypertonic.

40. Nematocysts are an adaptation used by _______ to inject toxin into a victim. a. jellyfish b. spiders c. snakes d. short-tailed shrews e. pufferfish

40. The pacemaker function in the mammalian heart is performed by the a. sinoatrial node. b. atrioventricular node. c. Purkinje fibers. d. bundle of His. e. ventricular mass.

41. A body's tolerance to its own molecules involves a. the removal of immature B or T cells that show the potential to mount a response against self antigens. b. the presence of class II MHC molecules on all cells. c. the presence of CD4 on most cells. d. apoptosis of all cells with class I MHC self antigens. e. suppression of the cellular immune response.

41. Which of the following represents the correct order in which action potentials spread from the atria to the ventricles during a normal heartbeat in the mammalian heart? a. Atrioventricular node bundle of His Purkinje fibers b. Atrioventricular node Purkinje fibers bundle of His c. Purkinje fibers bundle of His atrioventricular node d. Sinoatrial node Purkinje fibers bundle of His e. Sinoatrial node ventricular muscle cells Purkinje fibers

43. Action potentials a. initially cause depolarization of the membrane, usually followed by hyperpolarization. b. cause a return to resting potential when the sodium channels open. c. can be triggered in rapid succession, with no measurable delay between spikes. d. are initiated by the membrane's increased permeability to potassium. e. result from inactivation of leak channels.

43. In Las Vegas casinos, gamblers often roll the dice around in their hands before throwing them. Which type of mechanoreceptor is giving them information about the shape of the dice? a. Meissner's corpuscles b. Merkel's discs c. Ruffini endings d. Pacinian corpuscles e. Both a and c

45. The Golgi tendon organ is a type of mechanoreceptor found in tendons and ligaments. Action potentials from this structure inhibit spinal cord motor neurons. The main function of this structure is to a. measure the force of muscle contraction. b. provide information about deep pressure. c. innervate muscles. d. activate the Golgi apparatus within muscle cells. e. signal muscle contraction.

45. The frequency at which a single neuron can "fire" action potentials is limited by the a. refractory period for the closing of the voltage-gated Na+ channels. b. number of leak channels a neuron has. c. number of synapses formed by the neuron. d. time it takes for the voltage-gated Na+ channels to reopen. e. speed at which Cl‒ ion channels can close.

45. Which of the following statements about the transport of respiratory gases by the blood is false? a. The amount of O2 that can be dissolved directly in plasma is sufficient to support the resting metabolism. b. By binding O2, hemoglobin helps maintain the O2 concentration gradient. c. Internal ventilation of the gas exchange surfaces is dependent on blood flow. d. Each hemoglobin molecule can carry a maximum of four O2 molecules. e. Molecules of O2 are associated with the heme groups of hemoglobin.

45. Which of the following would you expect to find in a urine specimen collected from a healthy person? a. Water b. Glucose c. Red blood cells d. Plasma proteins e. Amino acids

46. Which of the following statements about fast-twitch fibers is true? a. They are more common in the leg muscles of champion sprinters than in champion marathon runners. b. They have more mitochondria than slow-twitch fibers have. c. They fatigue less rapidly than slow-twitch fibers do. d. Their abundance is more a product of training than of genetics. e. They are more common in postural muscles than in finger muscles.

47. Which of the following structures of the mammalian auditory system transduces (converts) pressure changes into action potentials that are carried by the auditory nerve back to the brain? a. Hair cells b. Ear ossicles c. Oval window d. Tympanic membrane e. Basilar membrane

48. The mature red blood cells of humans a. contain no nuclei or endoplasmic reticulum. b. are more than 75 percent hemoglobin. c. have a nearly spherical shape. d. have a relatively low surface area-to-volume ratio. e. have a rigid shape and low flexibility.

49. Movement of food from the stomach into the esophagus is normally prevented by a. a sphincter. b. reverse peristalsis. c. the pyloric sphincter. d. peristalsis. e. the pharynx.

49. The sound of the alarm clock in the morning triggers a(n) _______ in the sleeper. a. mechanoreceptor b. thermoreceptor c. electroreceptor d. chemoreceptor e. photoreceptor

49. Which of the following antibody classes is most likely to trigger a large release of histamines? a. IgE b. IgG c. IgM d. IgL e. Monoclonal

5. Breathing provides the body with the oxygen required to support the energy metabolism of all cells and also eliminates _______, one of the waste products of cell metabolism. a. carbon dioxide b. carbon monoxide c. carbon tetrachloride d. calcium carbonate e. carbonic acid

5. Neurons have different shapes and sizes depending on their role. A bipolar cell in the retina of the eye collects information from a few inputs and transmits it a short distance to one or more closely spaced neurons. What shape would you predict it to have? a. A few dendrites and a short axon with one or more terminals b. A long axon with many axon terminals c. A dense field of dendrites and a single axon d. Numerous dendrites and a long axon e. Dendrites and a highly branched axon

50. A human female has the most primary oocytes in her ovaries a. at birth. b. just before puberty. c. early in her fertile years. d. midway through her fertile years. e. at menopause.

50. A muscle reaches its maximum force of contraction when it is at _______ percent of its resting length. a. 100 b. 80 c. 60 d. 40 e. 20

50. Acetylcholine is a. a neurotransmitter. b. released by muscle cells at neuromuscular junctions in vertebrates. c. found in electrical synapses. d. released when there is a drop in the cytoplasmic concentration of Ca2+ ions. e. synthesized in the cell body.

50. Auditory information comes from hair cells in the ear that are concentrated in the a. organ of Corti. b. tympanic membrane. c. basilar membrane. d. semicircular canals. e. vestibular apparatus.

50. Once pathogenic bacteria have infected the urethra (in the urinary tract), they can move directly to the a. urinary bladder. b. ureter. c. proximal convoluted tubule. d. kidney. e. collecting duct.

50. Which the following statements about the adaptive immune system is false? a. Mammals have thousands of antibody genes. b. Different B cells develop from slightly different genomes. c. The random pairing of heavy and light chains helps produce antibody diversity. d. Each mature B cell can produce one, and only one, specific antibody targeted to a single epitope. e. B cells can change the class of immunoglobulin that they synthesize.

51. The function of leukocytes is to a. destroy foreign cells or to produce antibodies. b. transport respiratory gases. c. stimulate blood clotting. d. distribute nutrients to tissues. e. produce the different types of blood cells.

52. If a woman has scar tissue completely blocking both of her oviducts about halfway down their length, which of the following would be impossible without medical intervention? a. Fertilization b. Ovulation c. Buildup of the endometrium d. Menstruation e. All of the above

52. The sweetness that you taste if you keep chewing a piece of bread is due the action of the enzyme a. amylase. b. sucrase. c. lactase. d. maltase. e. pepsin.

52. When an action potential arrives at an axon terminal, the fusion of neurotransmitter vesicles with the cell membrane is triggered by a. an increase in the concentration of calcium ions within the cell. b. the removal of calcium ions from the cytoplasm of the cell. c. the opening of K+ leak channels, which causes an increase in potassium ions within the cell. d. the release of acetylcholine. e. a sudden increase in chloride ions within the cytoplasm of the cell.

53. Makes up the internal core, or medulla, of the kidneys a. Renal pyramid b. Proximal convoluted tubule c. Distal convoluted tubule d. Loop of Henle e. Collecting duct

53. The mechanisms of joining and random deletion account for only a part of antibody diversity. Vast numbers of unique immunoglobulins are also produced by a. mutations. b. translocations. c. cell fusion. d. cell surface proteins. e. All of the above

55. Class switching occurs as a result of a. genetic deletions in the immunoglobulin genes. b. clonal anergy. c. clonal deletion. d. imprecise recombination between the immunoglobulin genes. e. changes in the variable region.

55. In women, new follicles do not mature as long as the corpus luteum is maintained because a. the hormones released from the corpus luteum inhibit gonadotropin release. b. the hormones released from the corpus luteum inhibit ovarian secretion. c. the ovary receives negative feedback from the endometrial lining of the uterus. d. there is insufficient energy to support both maintenance of the corpus luteum and follicle development. e. the hormones released from the corpus luteum inhibit buildup of the endometrium.

55. The circulating protein fibrinogen contributes to blood clotting by a. polymerizing to form fibrin threads. b. acting as a catalyst for thrombin activation. c. binding to red blood cells. d. activating the platelets. e. triggering phagocytosis by the leukocytes.

56. Which of the following would increase the amount of oxygen diffusing from the lungs into the blood? a. An increase in the binding rate of O2 to hemoglobin b. A decrease in the partial pressure of O2 in the lungs c. An increase in the partial pressure of O2 in the blood d. A decrease in the red blood cell count e. An increase in the water vapor of air in the lungs

57. Fish have a lateral line system consisting of canals under the surface of the skin. These canals contain sensory structures consisting of hair cells capped by a cupula. These structures look similar to those found in our semicircular canals. When the fish swims, a stream of water flows through the lateral line canal. The most likely function of the lateral line sensory system in the fish is to sense a. pressure changes in the water. b. the depth of the water. c. chemical substances in the water. d. electrical currents in the water. e. spatial orientation based on gravity.

58. If you compare a claw hammer and a ballpeen hammer to T cell receptors, the heads of the hammers are most analogous to the a. variable regions. b. constant regions. c. α chains. d. γ chains. e. hydrophobic region.

58. The binding of acetylcholine on the motor end plate results in a(n) _______ in the muscle cell membrane. a. graded potential b. equilibrium potential for K+ c. hyperpolarization d. action potential e. influx of acetylcholinesterase

58. Which of the following statements about the effect of aerobic exercise on muscles is false? a. It increases the size, rather than the number, of muscle fibers. b. It increases the number of mitochondria. c. It increases the enzymes involved in energy use. d. It increases the density of capillaries delivering oxygen to the muscles. e. It increases the production of myoglobin.

59. In acidic tissues, hemoglobin releases _______ it does in less acidic environments. a. more O2 than b. less O2 than c. more CO2 than d. less CO2 than e. the same amount of O2 and CO2 as

6. Suppose three female sharks are housed without males in a large tank for many years. One morning the caretakers find a single pup swimming with one of the females. They test the pup's DNA and find that it is the same as that of the adult female. The pup likely resulted from a. parthenogenesis. b. budding. c. regeneration. d. sexual reproduction. e. sexual reproduction with delayed fertilization.

60. The three systems by which muscles obtain ATP a. differ in the capacity and rate at which they produce ATP. b. rely on the large amounts of ATP stored in muscle. c. produce similar amounts of ATP. d. rely on reactions within mitochondria. e. have similar time courses.

60. Which of the following statements about digestion is false? a. Enzymes that carry out the final step in the digestion of proteins are secreted by the pancreas. b. Enzymes that carry out the final step in the digestion of proteins produce absorbable tripeptides, dipeptides, and amino acids. c. Enzymes that carry out the final step in the digestion of the common disaccharides are produced by the intestinal epithelial cells. d. Enzymes that carry out the final step in the digestion of the common disaccharides produce absorbable monosaccharides. e. Unabsorbed lactose is metabolized by bacteria in the colon.

60. Which of the following statements about rhodopsin is false? a. In vertebrate eyes, the retinal and the opsin never separate from each other. b. When 11-cis-retinal absorbs light, it becomes all-trans-retinal. c. Rhodopsin is a transmembrane protein. d. Rhodopsin consists of a protein and a light-absorbing molecule. e. All animals that can sense light do so using rhodopsin.

61. If a planarian flatworm is positioned relative to a stationary light source such that more light-sensitive cells are stimulated in its right than in its left eye cup, the flatworm will a. turn to the left. b. turn to the right. c. make a complete clockwise circle. d. make a complete counterclockwise circle. e. stop moving.

62. The acidic chyme in the small intestine is neutralized in part by a. bicarbonate from the pancreas. b. buffers from the jejunum. c. bile from the liver. d. trypsin activation. e. a variety of zymogens.

64. Breathing rhythm is generated in the _______ and modified by neurons either in or above the _______. a. medulla; pons b. medulla; spinal cord c. spinal cord; pons d. spinal cord; cerebellum e. cerebellum; medulla

65. A scientist interested in studying aquaporins plans to examine the parts of mammalian nephrons in which large numbers of aquaporins can be found. This researcher would not choose to examine the a. thick ascending limb of loop of Henle. b. collecting duct. c. descending limb of loop of Henle. d. distal convoluted tubule. e. proximal convoluted tubule.

66. Which of the following hormones might be given to a woman who has experienced recurrent miscarriages? a. Progesterone b. Oxytocin c. Prolactin d. Inhibin e. Human chorionic gonadotropin

67. Breathing rhythm is generated in the _______ and is influenced by variation in levels of _______ in the blood. a. medulla; CO2 and O2 b. medulla; CO2 c. medulla; O2 d. frontal lobe; CO2 and O2 e. frontal lobe; CO2

67. When an individual rod cell is stimulated with light, its membrane potential a. becomes more negative. b. becomes more positive. c. becomes more positive than that of other neurons. d. begins to generate action potentials. e. begins to reduce membrane polarization.

69. Which of the following methods is the most effective form of birth control? a. Vasectomy b. Condom c. Intrauterine device d. Rhythm method e. Birth control pill

7. T cells mature in a. the thymus. b. lymph nodes. c. bone marrow. d. the spleen. e. the thoracic duct.

7. The nutritional disease kwashiorkor results from a(n) a. protein deficiency. b. vitamin deficiency. c. calorie deficiency. d. overdose of fat-soluble vitamins. e. overdose of thyroxine.

70. Which of the following is not considered to be autoimmune disease? a. AIDS b. Rheumatoid arthritis c. Type I diabetes d. Systemic lupus erythematosis e. Allergies

71. The respiratory rate in humans and other mammals changes in response to a. PCO2. b. PO2. c. PN2. d. PCO. e. turbidity

71. Which of the following statements about exoskeletons is false? a. During molting, the old exoskeleton is reabsorbed and a new exoskeleton forms. b. A clam shell is an exoskeleton. c. The arthropod cuticle is secreted by a layer of cells just below the exoskeleton. d. The inner layer of the arthropod exoskeleton provides a surface for muscle attachment. e. The arthropod exoskeleton is a continuous covering that is thinned at the joints.

72. A cross section of the spinal cord reveals white matter containing _______ and gray matter containing _______. a. axons; cell bodies b. cell bodies; axons c. the dorsal horn; the ventral horn d. the ventral horn; the dorsal horn e. afferent neurons; efferent neurons

72. Alcohol and stretch receptors in the aorta and carotid arteries are similar in that they a. inhibit antidiuretic hormone (ADH). b. stimulate antidiuretic hormone (ADH). c. inhibit aldosterone. d. stimulate aldosterone. e. stimulate atrial natriuretic peptide (ANP).

74. Which of the following statements about gastrin is false? a. It is activated by low pH. b. It stimulates secretion of HCl. c. It stimulates secretion of pepsin. d. It increases motility in the stomach. e. It is secreted in the lower part of the stomach.

78. Osteoblasts are cells that a. lay down new matrix on bone surfaces. b. are surrounded by matrix and remain in contact through thin cellular extensions. c. sit in lacunae that are connected by tiny channels. d. tear down old bone and deposit new bone. e. tear down old cartilage and deposit new bone.

79. In which of the following procedures does fertilization occur within the female reproductive tract? a. Artificial insemination b. In vitro fertilization (IVF) c. Intracytoplasmic sperm injection d. Both b and c e. None of the above

79. Workers who built the US Transcontinental Railroad exerted a tremendous amount of effort, creating tunnels through the Sierra Nevada mountains by breaking down the stone bit by bit. This step-by-step deconstruction process was analogous to the work performed in the body by a. osteoclasts. b. chondrocytes. c. osteoblasts. d. osteocytes. e. chondroblasts.

8. Organisms living in a freshwater environment normally a. excrete copious amounts of dilute urine and retain salts. b. excrete a small volume of dilute urine and retain salts. c. excrete copious amounts of concentrated urine. d. excrete small amounts of concentrated urine. e. conserve both water and salts.

8. The region composed of a presynaptic cell, its target cell, and the space between them is a a. synapse. b. nerve. c. vesicle. d. barrier. e. junction.

82. Which of the following statements about the hormonal control of fuel metabolism is false? a. During the absorptive period, the liver converts glycogen into glucose. b. During the postabsorptive period, the body cells preferentially use fatty acids for metabolic fuel. c. Cells of the nervous system depend almost exclusively on glucose for metabolic fuel. d. Glucagon plays a major role during the postabsorptive period by causing the liver to convert glycogen into glucose and stimulating gluconeogenesis. e. Cells of the pancreas release insulin during the absorptive period.

83. What gives the long bones of our arms and legs their strength, and allows them to resist both compressional and bending forces? a. Their shaft is a tube of primarily compact bone. b. Their extracellular matrix contains crystals of calcium carbonate. c. Their extracellular matrix consists mostly of collagen and polysaccharides. d. They have a high density of osteoclasts. e. They consist of lightweight cancellous bone with an internal meshwork of supporting elements.

87. If we compare a vertebrate jaw and knee joints as lever systems, a. the jaw joint can apply greater compressional forces than the knee joint can. b. their ratios of power arm to load arm are about the same. c. the knee joint has greater rotational abilities than the jaw does. d. the knee joint has a greater ratio of power arm to load arm than the jaw does. e. only the jaw is a hinged joint.

90. Which of the following statements about the skeletal system as a series of joints and levers is false? a. An extensor muscle moves a bone closer to the body. b. Antagonistic pairs include an extensor muscle and a flexor muscle associated with the same joint. c. Ligaments hold together bones that meet at joints. d. Tendons attach muscles to bones. e. The knee joint is a hinge joint.

1. If a red blood cell is in blood plasma with a solute concentration of 270 mosm/l, and the cytoplasm of the red blood cell is 300 mosm/l, then a. the volume of the red blood cell will not change. b. water will diffuse into the red blood cell, causing it to swell. c. water will diffuse out of the red blood cell, causing it to shrivel. d. there will be no net movement of water into or out of the red blood cell. e. solutes will be actively transported out of the red blood cell.

1. Two types of cells in nervous systems that are chiefly involved in encoding, processing, and storing information are a. axons and dendrites. b. neurons and glia. c. sensory neurons and motor neurons. d. presynaptic and postsynaptic cells. e. nerve and muscle cells.

10. Certain amino acids are called essential amino acids because they a. are required for making protein. b. cannot be made from other amino acids and must be obtained from food. c. are universally needed by all animals. d. are essential as an energy source. e. are required for making nucleic acids.

10. Which muscle type has a pacemaking function? a. Smooth b. Cardiac c. Skeletal d. Both a and b e. All of the above

15. A disease in which antibodies destroy myelin produced by oligodendrocytes would most likely cause which of the following? a. The blood-brain barrier would be weakened and toxins would easily pass into the brain. b. Neurons in the brain and spinal cord would conduct action potentials more slowly. c. Action potential conduction in neurons in the peripheral nerves would be slower. d. Neurons in the brain would be deprived of nutrients. e. The dendrites of peripheral nerves would not process information from other neurons.

15. If you brush against a doorway as you enter a room, you will trigger a. ion flow through voltage-gated ion channel. b. the opening of a pressure-sensitive cation channel. c. a metabotropic sensory receptor. d. a second messenger system. e. a signal transduction cascade.

16. Which of the following is not one of the reasons that diffusion of O2 into an animal is more problematic than diffusion of CO2 from an animal? a. CO2 is more soluble in water than O2 is. b. Cellular respiration produces less CO2 than the O2 that is consumed. c. The CO2 content of air is less than the O2 content. d. The atmospheric partial pressure of O2 is greater than the atmospheric partial pressure of CO2. e. There is a greater concentration gradient from the cell to the atmosphere for CO2 than for O2.

16. Which of the following statements about vitamins is false? a. Vitamins, like essential amino acids and fatty acids, are organic molecules. b. Most vertebrates require the same vitamins. c. Vitamins function mostly as, or as parts of, coenzymes. d. Vitamins are required only in very small amounts. e. Humans require more water-soluble vitamins than fat-soluble vitamins.

17. The terms "ammonotelic," "ureotelic," and "uricotelic" refer to a. the actions of hormones on the excretory system. b. types of nitrogenous waste produced by animals. c. pathways of kidney evolution. d. modifications of kidney tubules that enhance excretion. e. modes of excretory system development.

18. The respiratory system of insects consists of a. branched air tubes called spiracles that supply blood capillaries. b. branched air tubes called tracheae and tracheoles that end in air capillaries. c. branching gill systems that end in openings called tracheae. d. branching gill systems that end in openings called spiracles. e. extensive layers of gas exchange tissue just under the exoskeleton.

19. A paleontologist finds a fragment of a fossilized vertebrate that indicates that the animal had a three-chambered heart. The animal could have been a(n) a. tuna. b. salamander. c. crocodile. d. eagle. e. Both b and c

19. Defensins, which are toxic to a wide range of pathogens, are produced by a. lymph nodes. b. mucous membranes. c. bone marrow. d. mast cells. e. the thymus.

2. If the vaccination rate for polio in a given country is at 60 percent of the population, it is reasonable to conclude that a. "herd immunity" is in place. b. another 10‒20 percent of the population would have to be immunized before the disease is controlled or eradicated. c. transmission to infants will cease. d. older people are extremely unlikely to contract the disease. e. further immunizations will not be cost-effective.

2. Which of the following statements about asexual reproduction is false? a. It occurs in some species of fishes, amphibians, and reptiles. b. Asexually reproducing species tend to live in variable environments. c. Asexually reproducing species tend to be sessile. d. Asexually reproducing species tend to live in sparse populations. e. One method of asexual reproduction is parthenogenesis.

2. Which of the following statements about open circulatory systems is false? a. A pump is usually present. b. Blood is pumped out of openings in the heart called ostia. c. The blood is part of the extracellular fluid. d. Interstitial fluid bathes the tissues directly. e. They are found in mollusks and arthropods.

20. Which of the following characterizes both spermatogenesis and oogenesis in humans? a. A period of developmental arrest in prophase I of meiosis b. Reproductive stem cells that arrive in the gonad during development and proliferate by mitosis c. The production of four haploid gametes d. The completion of a second meiotic division at fertilization e. A period of developmental arrest after the first meiotic division

20. Which of the following statements about respiratory adaptations is false? a. Internalization of respiratory surfaces leads to the need for ventilation. b. External gills are found only in invertebrates. c. Some fishes ventilate their gills by swimming almost constantly with their mouths open. d. In fish, water flows unidirectionally into the mouth, over the gills, and out from under the opercular flaps. e. Desiccation of the respiratory surface is more likely to occur in lungs than in gills.

20. Which of the following statements about sensory cells is false? a. Sensory cells can produce gradually diminishing responses to repeated stimulation. b. Sensory cells can respond equally to all types of stimuli. c. Changes in stimulus strength can lead to changes in the frequency of action potentials generated by sensory cells. d. Sensory cells display a phenomenon called adaptation. e. Some sensory cells are assembled with other cell types that enhance their ability to collect, filter, and amplify stimuli.

21. The benefit of having at least a partial separation of pulmonary and systemic circulation is that a. oxygenated and deoxygenated blood are separated. b. blood moving to the body tissues is at a higher pressure than it would be if it had flowed through the lungs first. c. blood moving to the lungs is at a higher pressure than it would be if it had come directly from the body. d. blood moving to the body tissues is at a lower pressure than it would be if it had flowed through the lungs first. e. there are two muscular regions for pumping.

22. When an action potential arrives at the neuromuscular junction, acetylcholine is released into the synaptic cleft and binds to receptors in the postsynaptic membrane. Which of the following represents the correct order of the next series of events? a. Calcium is released from the sarcoplasmic reticulum, an action potential travels down the T tubules, depolarization spreads through the T tubule, and myosin binds actin. b. An action potential travels down the T tubules, depolarization spreads through the T tubule, calcium is released from the sarcoplasmic reticulum, and myosin binds actin. c. An action potential travels down the T tubules, depolarization spreads through the T tubule, calcium is taken up by the sarcoplasmic reticulum, and myosin binds actin. d. An action potential travels down the T tubules, depolarization spreads through the T tubule, ATP binds to myosin, and myosin binds actin. e. A T tubule is depolarized, calcium is released from the sarcoplasmic reticulum, an action potential is created in the muscle cell, and myosin binds actin.

22. Which of the following is not an adaptation seen in fish gills? a. A countercurrent exchange system b. Bidirectional ventilation of the gills c. Morphological features that increase the surface area available for gas exchange d. Morphological features that decrease the path length for diffusion of the respiratory gases e. Morphological features that maximize the efficiency of O2 extraction

24. What is the role of Ca2+ in the control of muscle contraction? a. It causes depolarization of the T tubule system. b. It changes the conformation of troponin, thus exposing myosin-binding sites. c. It changes the conformation of myosin heads, causing actin and myosin filaments to slide past each other. d. It binds to tropomyosin and breaks actin-myosin cross-bridges. e. It blocks the ATP-binding site on myosin heads, enabling muscles to relax.

25. The greatest intensity of perceived smell comes from the a. enzyme that binds with the most odorant molecules. b. odorant that binds to the most receptors. c. greatest variety of odorant molecules. d. greatest threshold of depolarization. e. greatest number of odorant molecules entering the cell.

25. Vitamin D is obtained by different people in various ways. For example, a. dark-skinned people of high latitudes, such as the Inuit, obtain it from sunlight. b. dark-skinned people of low latitudes obtain it from tropical sunlight. c. some people obtain it from protein molecules that absorb sunlight. d. some people obtain it from water-soluble components of foods. e. light-skinned people of middle latitudes obtain it from drinking water.

25. Which of the following statements about the resting potential of a neuronal cell membrane is true? a. The inside is about 60 millivolts more positive than the outside. b. The outside is about 60 millivolts more positive than the inside. c. The inside is about 30 millivolts more positive than the outside. d. The outside is about 30 millivolts more positive than the inside. e. The inside has about the same charge as the outside.

26. In the excretory systems of both flatworms and annelids, a. flame cells drive reabsorption. b. pressure differences drive filtration. c. nephridiopores open to the outside of the animal. d. there is active transport of nitrogenous wastes into excretory tubules. e. there is a close association between excretory tubules and capillaries.

26. Which product of oogenesis acquires the energy, raw materials, and RNA needed for the first cell divisions after fertilization? a. Second polar body b. Primary oocyte c. Secondary oocyte d. First polar body e. Ootid

27. Which of the following characterizes the lungs of mammals? a. Air sacs b. Tidal ventilation c. Complete emptying in exhalation d. Crosscurrent air flow e. Countercurrent air flow

28. Which of the following statements about smooth muscle is false? a. Smooth muscle is under the control of the autonomic nervous system. b. Smooth muscle cells are multinucleated. c. Smooth muscle appears unstriated when viewed with the microscope. d. Gap junctions are common in smooth muscle. e. Stretched smooth muscle will contract.

28. Which of the following structures or regions in a four-chambered vertebrate heart contains blood with the lowest O2 concentration? a. Pulmonary vein b. Pulmonary artery c. Left atrium d. Aorta e. Arteriole end of a systemic capillary

29. If a physical or chemical stimulus causes a change in a cell's membrane potential, a direct effect of that change may be a. an increase in Na+ concentration outside the cell. b. increased permeability of the plasma membrane to certain ions. c. an increase in pumps. d. an increase in the number of K+ ions needed to reach equilibrium. e. an increase in the lipid composition of the membrane.

29. The nutritional disease beriberi results from a(n) a. protein deficiency. b. vitamin deficiency. c. calorie deficiency. d. overdose of fat-soluble vitamins. e. overdose of thyroxine.

29. The resting potential of smooth muscle cells is a. not likely to fire action potentials. b. affected by the stretching of the cells. c. more negative than that of most cells. d. unaffected by nearby potential change. e. nearly zero.

3. A flea can jump up to 200 times its body length because a. it has very powerful muscles. b. it compresses and then releases an elastic material in its legs. c. it compresses water, which jets out of small holes in its carapace. d. its muscles are assisted by vestigial wings. e. it takes advantage of the shape of its carapace and glides.

3. When elephants are swimming, which of the following protects the blood vessels around their lungs from water pressure damage? a. Swimming only in shallow water b. Dense connective tissue that attaches their lungs to the chest cavity c. Breath-holding d. Thick-walled blood vessels near their lungs e. Ribs surrounding their blood vessels

30. "Systole" and "diastole" refer to the _______ and _______, respectively, of the _______ in mammals. a. relaxation; contraction; ventricles b. contraction; relaxation; ventricles c. relaxation; contraction; atria d. contraction; relaxation; atria e. None of the above

30. Some of the best-studied examples of chemosensory receptors are those in Bombyx mori, a member of the _______ group. a. cephalopod b. arthropod c. chordate d. ctenophore e. annelid

31. Which of the following is correct pairing of a similarity of marine and freshwater bony fishes and a difference between them? a. Both lose uric acid across their gills; marine bony fishes produce a minimal amount of urine, whereas freshwater bony fishes produce a copious amount of dilute urine. b. Both lose ammonia across their gills; marine bony fishes produce a minimal amount of urine, whereas freshwater bony fishes produce a copious amount of dilute urine. c. Both raise osmolarity of their body fluids; marine bony fishes produce a minimal amount of urine, whereas freshwater bony fishes produce a copious amount of dilute urine. d. Both raise osmolarity of their body fluids; marine bony fishes excrete excess salt across their gills, whereas freshwater bony fishes conserve salt. e. Both lose ammonia across their gills; freshwater bony fishes produce a minimal amount of urine, whereas marine bony fishes produce a copious amount of dilute urine.

33. In their classic experiments to determine the electrical properties of neurons, Hodgkin and Huxley used a. fluid-filled pipettes to sample the cytoplasm of a rat spinal cord neuron. b. electrodes inserted on either side of the plasma membrane of the squid giant axon. c. batteries to cause electrical changes in the membrane potential of sensory neurons. d. patch clamps to determine the activity of individual ion channels in brain neurons. e. recording pipettes to measure the activity of ion channels in the giant axons of earthworms.

34. During the cardiac cycle in mammals, the blood pressure in the aorta is at a minimum a. at the end of systole. b. at the beginning of systole. c. at the beginning of diastole. d. when the physician hears the "dub" sound with the stethoscope. e. None of the above

35. One of the most serious effects of cigarette smoking on the lungs is the a. removal of mucus from the airways. b. immobilization of cilia lining the airways. c. speeding of airflow through the airways. d. increase in surfactant action that it causes. e. increase it induces in the surface area of alveoli.

35. To test the response of mouse A to the presence of mouse B in its cage, researchers temporarily prevent neurons in the vomeronasal organ of mouse A from firing. Which of the following would be mouse A's predicted response? a. It would not be aware of mouse B. b. It would not distinguish the gender of mouse B. c. It would respond to pheromones from mouse B. d. It would lose its sense of smell and taste. e. Neurons in the accessory olfactory bulb would respond to the presence of mouse B.

36. Which of the following statements about surfactants in the lungs is false? a. Lung surfactant is a detergent-like substance. b. Surfactants increase the cohesive forces between water molecules. c. Certain cells in the alveoli produce surfactants. d. Surface tension influences the amount of effort required to inflate the lungs. e. Premature infants suffer respiratory distress syndrome if natural surfactants are not present within the lungs.

37. A mammal with a diet of grain and leaves would be expected to have which kind of teeth? a. Prominent canine teeth and small molars b. Prominent molars and small canines c. Prominent molars and small premolars d. A balanced set of incisors, molars, and canines e. Prominent canine teeth and small incisors

37. Which of the following is not a component of mammalian semen? a. Seminal fluid from the seminal vesicles b. Sertoli cells, which provide nutrients for the sperm c. Alkaline secretions from the prostate gland d. Sperm e. Fibrinogen

38. Gap junctions a. electrically isolate cardiac muscle cells. b. allow large numbers of cardiac muscle cells to contract in unison. c. provide enough strength to withstand the large pressure generated by the ventricles. d. are found only in the cardiac muscle cells of the ventricles. e. are especially abundant in the muscle cells between the atria and ventricles.

39. Action potentials are generated in a mechanoreceptor when a. ion channels close in response to membrane distortion. b. ion channels open in response to membrane distortion. c. receptors bind chemicals in response to pressure. d. the sensitivity of the membrane to neurotransmitters increases. e. signals from other mechanoreceptors are summated.

4. In the early 1900s, oyster fishermen cut sea stars (starfish), which are predators of oysters, into pieces and threw them back into the sea. This practice led to an explosion in the sea star population because a. other sea stars ate the pieces and were able to increase their reproductive output. b. each arm with a portion of the central disc regenerated into a new individual. c. competition was removed from the stronger sea stars that were not caught, allowing them to increase their reproductive output. d. the oyster population grew in response to this new supply of food, allowing the population of their predators to increase as well. e. each arm could form a new individual through budding.

40. In humans, the process of exhalation is brought about in large part by a. the contraction of external intercostal muscles. b. elastic recoil of the lung tissues. c. the contraction of the diaphragm. d. complete collapse of the lung tissue. e. low pressure in the thoracic cavity.

40. The removal of immature B and T cells is called clonal a. anergy. b. deletion. c. selection. d. attenuation. e. inactivation.

41. In this scenario, the disassembly room is analogous to the _______ in a digestive system. a. esophagus b. stomach c. microvilli d. intestine e. rectum

41. Which of the following statements about slow-twitch and fast-twitch muscles is true? a. One is smooth muscle and one is skeletal muscle. b. They express different genes in their myosin molecules. c. One occurs only in mammals. d. They typically have similar numbers of mitochondria per cell. e. Those with low ATPase activity compensate by quickly recycling their actin-myosin bridges.

42. Drugs used to treat erectile dysfunction act to a. block nitric oxide (NO). b. prolong the effects of nitric oxide (NO). c. increase testosterone. d. increase gonadotropin-releasing hormone (GnRH). e. prolong the activity of enzymes that break down the second messenger cGMP.

43. In the vertebrate kidney, the process of filtration from the capillaries into Bowman's capsule is driven by a. active transport. b. arterial blood pressure. c. venous blood pressure. d. osmotic pressure. e. secretion.

43. Which of the following must take place in order for a B cell to become an antibody-secreting plasma cell? a. Monoclonal antibody production of two distinct epitopes per antibody b. Binding to an antigen by the B cell and a T-helper cell with the same specificity as the B cell c. The production of IgE, followed by production of IgG d. The production of IgG, followed by production of IgE e. The activation of class I MHC proteins

44. A tumor in a Leydig cell would most directly affect the a. production of inhibin. b. production of testosterone. c. secretion of gonadotropin-releasing hormone (GnRH). d. secretion of follicle-stimulating hormone (FSH). e. secretion of luteinizing hormone (LH).

45. Among different immunoglobulins, the amino acid sequences of the _______ regions are similar, and the amino acid sequences of the _______ regions are different. a. constant; specific b. constant; variable c. specific; constant d. specific; variable e. variable; constant

46. Regarding renal clearance in humans, foreign substances such as drugs would most likely be a. reabsorbed at Bowman's capsule. b. secreted into the renal tubule. c. reabsorbed at the glomerulus. d. secreted into the blood. e. reabsorbed into the filtrate.

46. Which layer of the vertebrate gut shows adaptations for increasing absorptive surface area? a. Lumen b. Mucosa c. Submucosa d. Serosa e. Peritoneum

48. Communication between neurons and other cells takes place through _______ and _______ synapses. a. presynaptic; postsynaptic b. chemical; electrical c. neuromuscular; neurotransmitter d. axonal; dendritic e. terminal; potential

48. Which of the following is the correct sequence of structures through which a mammalian sperm passes before fertilizing an egg? a. Uterus, vagina, cervix, oviduct, ovary b. Vagina, cervix, uterus, oviduct c. Oviduct, uterus, vagina, ovary, body cavity d. Vagina, cervix, oviduct, uterus e. Vagina, uterus, oviduct, body cavity

50. Hemoglobin delivers O2 to body cells from the red blood cells a. until the hemoglobin is depleted of O2. b. until the partial pressures of O2 in the two different cells are equivalent. c. although the hemoglobin is never completely saturated. d. by releasing O2 to cells with a higher partial pressure of oxygen. e. until the fluid pressure in the red blood cells is lower.

51. A muscle's capacity to be shortened is limited by a. bones, which eventually impede further contraction. b. the amount of overlap of actin and myosin, which eventually causes myosin to push against the Z line. c. the amount of overlap of actin and myosin, which eventually causes actin to push against the Z line. d. the water component of fiber cell cytoplasm, which is incompressible. e. All of the above

51. All of the following structures are encountered by a food bolus as it is swallowed except for the a. epiglottis. b. larynx. c. soft palate. d. pharynx. e. esophagus.

51. At birth, a female has about one million primary oocytes in each ovary. During a woman's fertile years, about _______ of these oocytes will mature and be released at ovulation. a. 100 b. 450 c. 900 d. 2,000 e. 4,500

51. In the vertebrate neuromuscular junction, acetylcholine is transmitted from the presynaptic neuron to the postsynaptic motor end plate through a. endocytosis of acetylcholine. b. diffusion. c. formation of vesicles in the motor end plate. d. acetylcholine membrane pumps. e. closing of voltage-gated Ca2+ channels.

51. Which the following is not considered one of the mechanisms that generates diversity in the human immune response? a. DNA rearrangements within B cells during their differentiation b. Insertion of RNA sequences into the DNA coding for antibody production c. Combinations of different alleles at each of several loci within immunoglobulin supergenes d. Spontaneous mutations in immunoglobulin genes e. DNA recombination events during B cell development

52. The structure into which filtrate flows from Bowman's capsule a. Renal pyramid b. Proximal convoluted tubule c. Distal convoluted tubule d. Loop of Henle e. Collecting duct

54. In women, a drug that blocks the LH surge would most immediately prevent a. a peak in estrogen. b. ovulation. c. a peak in progesterone. d. implantation of a fertilized egg. e. degeneration of the corpus luteum.

56. The main site of glucose and amino acid reabsorption a. Renal pyramid b. Proximal convoluted tubule c. Distal convoluted tubule d. Loop of Henle e. Collecting duct

56. Which of the following is not one of the components normally found circulating in the plasma? a. Platelets b. Fibrin c. Albumin d. Prothrombin e. Both a and c

57. If you compare a claw hammer and a ballpeen hammer to T cell receptors, the handles of the hammers are most analogous to the a. variable regions. b. constant regions. c. chains. d. chains. e. antigen‒MHC binding region.

58. In the mammalian ovary, thecal cells of the follicle are stimulated by luteinizing hormone (LH) to produce testosterone. Thecal cells are therefore similar to a. granulosa cells of the follicle. b. Leydig cells in the testes of males. c. Sertoli cells in the testes of males. d. primary oocytes. e. cells of the corpus luteum.

58. Most absorption of nutrients in the digestive tract takes place in the a. stomach. b. small intestine. c. large intestine. d. liver. e. pancreas.

58. The carcass of a newly discovered deep-diving species of whale washes up on shore, and biologists scramble to study the adaptations that allow it to circulate blood when it is under pressure at depth. A cross section of its flipper shows what seems to be a vein and an artery running parallel. The artery would be the structure a. with the largest interior diameter. b. with more muscle tissue and elastin in the wall. c. lined with endothelium. d. with valves to prevent backflow. e. All of the above

58. The structure characterized by numerous microvilli on cells a. Renal pyramid b. Proximal convoluted tubule c. Distal convoluted tubule d. Loop of Henle e. Collecting duct

58. When humans have acclimated to high altitudes, their hemoglobin a. is more saturated with O2 than it was at lower altitudes. b. delivers more O2 to tissues as the level of BPG increases. c. is more concentrated in red blood cells than it was at lower altitudes. d. shifts its O2-binding curve to the left. e. resembles fetal hemoglobin in terms of its O2-binding function.

6. In animals with a closed circulatory system, the liquid around the body cells is called a. blood plasma. b. interstitial fluid. c. mesolymph. d. hemolymph. e. aguavida.

6. Sensory cells transduce specific physical or chemical stimuli a. to magnetic energy. b. into a change in membrane potential. c. from an action potential into a synaptic signal. d. by summing local potentials. e. by amplification of the stimulus.

60. Which of the following statements is true? a. The T cell receptor is an immunoglobulin. b. The receptors on T lymphocytes are smaller than those on B lymphocytes. c. T cell receptors bind to intact antigens. d. T cell activation is part of the innate immune response. e. Activated T cells release antibodies.

61. Blood pressure is _______ than osmotic pressure at the arterial end of a capillary bed, which is where the process of _______ occurs. a. greater; reabsorption b. greater; filtration c. lesser; reabsorption d. lesser; filtration e. lesser; edema

61. The cells lining the proximal convoluted tubule have numerous microvilli and mitochondria. This indicates that these cells a. engage in the rapid diffusion of water. b. carry out reabsorption and active transport. c. store salts. d. produce urea. e. are metabolically inactive.

62. When a T cell is activated by an antigen, it will most likely a. secrete antibodies. b. proliferate. c. die. d. display the antigen on its cell surface using its class II MHC molecules e. become a plasma cell.

62. Which of the following is not one of the systems that supplies muscles with the ATP needed for contraction? a. Immediate system b. Pyruvic system c. Glycolytic system d. Oxidative system e. Both a and d

63. Given the total energy supply in the human body (in the form of ATP and creatine phosphate), how long is it possible for a human to sit at rest without replenishing the supply? a. 30 seconds b. 10 minutes c. 5 minutes d. 30 minutes e. 1 second

64. A chemical synapse differs from an electrical synapse in that a chemical synapse a. allows for faster transmission of a signal. b. allows for many more synaptic inputs per cell. c. does not allow for temporal summation of synaptic inputs. d. requires a larger area of cell‒cell contact. e. cannot be inhibitory.

65. Which of the following statements about valves is false? a. Defective heart valves produce sounds called heart murmurs. b. Veins and lymphatic vessels have two-way valves. c. Varicose veins result from the failure of valves within veins to prevent backflow of blood. d. The pulmonary valve is located between the right ventricle and the pulmonary artery. e. Atrioventricular valves prevent backflow of blood into the atria when the ventricles contract.

65. Women are encouraged to nurse their babies as soon as possible after giving birth because a. prolactin released in response to a baby's suckling promotes the mother-child bond. b. oxytocin released in response to a baby's suckling augments uterine contractions, which helps to reduce the size of the uterus and stop bleeding. c. such contact prompts the release of pain-reducing chemicals by the brain. d. the absence of a baby's crying stimulates greater release of oxytocin. e. the infant needs immediate nutrition, since it can no longer rely on the placenta.

66. How does cotransport of sodium in a symport facilitate glucose absorption? a. Active transport of sodium aids in salt uptake. b. When sodium diffuses into cells, glucose is carried along with it. c. When sodium is pumped into cells, glucose moves out of the cells. d. Sodium and glucose both diffuse into cells from the gut. e. Glucose is actively transported into the gut.

66. Which of the following is a scenario in which skeletal muscles pull on other skeletal muscles, rather than pulling on a skeleton? a. A person is performing a chin-up b. An elephant is moving its trunk c. A person is turning his or her head from left to right d. Muscle contractions are being used to maintain posture e. None of the above

67. Information about a sensory stimulus such as touch can be prevented from reaching the central nervous system by chemically blocking a. touch receptors in the central nervous system. b. afferent neurons of the sensory cells detecting touch. c. graded potentials in interneurons. d. efferent neurons carrying information to the spinal cord. e. neurotransmitter release in the brain.

68. The Frank-Starling law suggests that during exercise, the a. flow of blood through the heart speeds up. b. heart is stretched and contracts more forcefully. c. veins expand to handle increased blood flow. d. heart fills to capacity with blood at each beat. e. valves in veins cannot prevent backflow.

68. When you decide to mark a particular answer to this question, your nervous system sends the command to your hand to do so. That command is carried into your hand by axons of a. afferent neurons. b. efferent neurons. c. interneurons. d. sensory neurons. e. ganglion cells.

69. Which of the following statements about the lymphatic system is false? a. The lymphatic system conducts lymph from the lymph capillaries to the thoracic duct, where it enters the circulatory system. b. Lymph is identical to blood except that it does not contain erythrocytes. c. Lymphoid capillaries are distributed throughout the body. d. Lymph is propelled by contraction of skeletal muscles. e. Lymph nodes are an important part of the defense system that combats infections.

69. Which of the following statements about the molecular events of photoreception is false? a. A single photon can excite a rhodopsin molecule. b. In a well-lit setting, most of the sodium channels of a rod cell are open. c. cGMP keeps the sodium channels open. d. Activated phosphodiesterase (PDE) catalyzes the reaction hydrolyzing cGMP into GMP. e. Activated transducin activates PDE.

69. Which of the following statements about the skeletal system of the clam is true? a. It is an endoskeleton. b. It consists of a shell made up primarily of protein strengthened by minerals. c. Muscles attached to regions of the endoskeleton cause movement. d. Muscles are attached to the endoskeleton by tendons. e. All of the above

7. Which of the following is not associated with asexual reproduction? a. Identical genetic makeup of parent and progeny b. Fertilization c. Sexual behavior d. Identical genetic makeup of offspring e. Difficulty searching for mates

71. Rheumatoid arthritis may arise a. from the overproduction of IgE from mast cells. b. due to difficulty in shutting down the T cell response to self antigens. c. due to a delayed hypersensitivity to antigens d. when B cells lose their ability to become plasma cells. e. when class switching from IgM to IgG is inhibited.

71. The contragestational pill Mifepristone (RU-486) blocks _______ receptors. a. luteinizing hormone b. progesterone c. estrogen d. follicle-stimulating hormone e. gonadotropin-releasing hormone

71. Which of the following could be considered analogous to the vertebrate gut? a. An assembly line producing cars b. A junkyard where pieces of cars are removed one by one c. A cornfield capturing sunlight to form carbohydrates d. A migrating herd of wildebeest e. A chef combining ingredients to produce a meal

72. If you enter a lighted room and then turn off the lights so that you are now in the dark, what would you predict would occur to the rod cells in your retina? a. They would release less neurotransmitter in the dark. b. The membrane potential would be hyperpolarized and then become depolarized. c. The membrane potential would be depolarized and then become hyperpolarized. d. Na+ entry into the cell would decrease in the dark. e. Rhodopsin in the rod cells would activate transducin.

72. Which of the following statements about the endoskeletons of vertebrates is false? a. The muscles are attached to a living support structure. b. The rib bones are part of the appendicular skeleton. c. They allow the animal to expand without molting. d. They consist of bone and cartilage. e. At least two bones are required to form a joint.

73. Eating a small serving of a food that is very acidic might present something of a paradox to your stomach because a. the stomach can handle a low pH well, but might not detect the food's presence if the serving size is too small. b. the presence of food in the stomach typically causes release of gastrin, but low pH inhibits release of gastrin. c. it could lead to overly acidic conditions in the stomach by increasing the pH. d. the presence of food in the stomach typically causes release of pepsin, but low pH inhibits release of pepsin. e. the high pH of the food could trigger the release of bile in the stomach.

73. Which of the following statements about cartilage and bone is false? a. Some vertebrate skeletons are composed entirely of cartilage, with no bone. b. Adult human skeletons are composed entirely of bone, with no cartilage. c. Bone contains crystals of calcium phosphate. d. The endoskeleton in many vertebrates serves as a reservoir of calcium. e. A principal extracellular fiber in cartilage is collagen.

74. Alcohol inhibits antidiuretic hormone (ADH), which results in the production of a. large amounts of concentrated urine. b. large amounts of dilute urine. c. a small volume of dilute urine. d. a small volume of concentrated urine. e. no urine.

74. Which of the following statements about color vision is false? a. Three different types of cone cells in the human retina contribute to color vision. b. The absorption spectra of cone cells differ because of molecular differences in the retinal molecules. c. Rods do not contribute to color vision. d. The different rhodopsins in the human retina differ in the range of wavelengths of light they absorb best. e. Nocturnal animals often have poor color vision.

75. Which of the following is not one of the results of the release of atrial natriuretic peptide (ANP)? a. Decreased reabsorption of sodium b. Decreased water in the urine c. Decreased reabsorption of water d. Lowered blood volume e. Lowered blood pressure

76. In humans, the region of the brain that is the largest, and that is also more complex than that of most other vertebrate species, is the a. hindbrain. b. cerebrum. c. olfactory lobe. d. cerebellum. e. brainstem.

76. Which of the following is a primary factor in causing an HIV infection to progress to a deficiency in the immune system of a person? a. Pneumonia caused by a bacterial infection b. Antibodies made against HIV-infected cells c. HIV circulating free in blood plasma d. Activation of T-helper cells by HIV e. An increase in T cells

77. A physician is discussing methods of contraception with a married couple. The husband and wife are both 35 years old, they have two children, and they have decided that their family is complete. The woman also had two difficult pregnancies and has learned that a third pregnancy could pose a risk to her health. Which of the following methods would the physician be likely to recommend to this couple? a. Tubal ligation b. Vasectomy c. Condom d. Intrauterine device e. Spermicidal jelly

77. Bone tissue includes _______ cells enclosed in a matrix containing _______. a. osteoblast; polysaccharide b. osteocyte; collagen and calcium phosphate c. osteocyte; myosin and actin d. chondrocyte; calcium phosphate e. chondroblast; polysaccharide

78. Which of the following cell layers occurs farthest from the incoming light in the retina? a. Horizontal b. Photoreceptors c. Bipolar d. Amacrine e. Ganglion

79. Which of the following molecules contain mostly triglycerides and transport them to fat cells in tissues? a. Chylomicrons b. Very low-density lipoproteins (VLDLs) c. Low-density lipoproteins (LDLs) d. High-density lipoproteins (HDLs) e. Cholecystokinins

79. Which of the following statements about AIDS is false? a. The chances of getting the disease are increased if an individual already has a sexually transmitted disease. b. AIDS stands for "autoimmune deficiency syndrome." c. Most people who die from AIDS do not die because of HIV infection directly, but from other infections that would normally be eliminated by T cells. d. HIV can be transmitted through the blood of an infected mother to her child. e. HIV infections can be transmitted through sexual intercourse when a condom is not used.

81. The effects of glucagon include a. stimulating glucose uptake into cells. b. stimulating liver cells to break down glycogen. c. controlling blood glucose in the absence of insulin. d. stimulating cells to store energy as fat. e. None of the above

83. The protein leptin a. is produced by cells of the hypothalamus. b. signals the brain about the status of body fat reserves. c. is found in lower-than-normal levels in most obese humans. d. serves as a positive feedback signal to the brain to limit food intake. e. is an environmental toxin that accumulates in body fat.

84. Stretch receptors in the aorta and carotid arteries a. detect atherosclerosis. b. detect changes in blood pressure and relay them to the brain. c. constrict arteries when available O2 is low. d. detect when a flexor muscle is stretched too far and then pump more blood to the muscle. e. None of the above

9. In a crayfish, the receptor potential of a stretch receptor a. is the result of an action potential from the same cell. b. spreads when ion channels in the cell's dendrites are opened. c. starts at the axon hillock. d. decreases when the muscle is stretched. e. is created by the opening of ion channels in the axon.

9. Which of the following statements about undernourishment is false? a. One-sixth of the world's population is undernourished. b. Several weeks of fasting are required to deplete glycogen reserves. c. Self-imposed starvation is called anorexia nervosa. d. The loss of blood proteins during starvation leads to edema. e. During starvation, fat reserves are exhausted before the metabolism of body protein is accelerated.

1. Organisms that derive their energy and molecular nutrients from other organisms are called a. autotrophs. b. herbivores. c. heterotrophs. d. photosynthetic. e. protists.

1. Sexual reproduction has an evolutionary advantage over asexual reproduction because it a. results in both males and females of a species. b. is a more lengthy process. c. promotes genetic variability that potentially enables a population to adapt to a change in the environment. d. is controlled by many hormonal mechanisms. e. protects and nurtures the embryo.

1. The hydra is a small invertebrate related to the jellyfish. Which of the following characteristics of the hydra makes it unnecessary for the animal to have a cardiovascular system? a. It is aquatic. b. It has no skeleton. c. It consists of only two cell layers. d. It has tentacles to move water. e. It does not move rapidly.

10. A college student taking a 24-hour bus trip to her summer internship is surrounded by people sniffling and sneezing. She cannot escape the pathogen involved, but she does not share the others' symptoms during her trip. Which of the following is not involved in her resistance to the illness? a. Mucus b. Lysozymes c. T cells d. The innate defense provided by her skin e. Phagocytosis

10. Small insects may take a bubble of air underwater when they dive. The bubble can serve as an air tank for some time because a. as CO2 increases, the bubble inflates. b. as O2 is consumed, air pressure in the bubble decreases. c. as O2 is consumed, more O2 diffuses into the bubble. d. the partial pressure of nitrogen remains constant. e. for each O2 molecule used, a CO2 molecule replaces it.

11. The circulatory system of an earthworm includes all of the following except a. contractile vessels. b. a large dorsal vessel. c. capillary beds in the lungs. d. small vessels in each segment. e. a large ventral vessel.

12. Cartilaginous fishes (sharks and rays) have a specialized gland that excretes excess salt taken in with their food. Which of the following organisms also possess a gland for excreting excess salt acquired through their food? a. Terrestrial herbivores b. Marine mammals c. Marine birds d. Brine shrimp e. Freshwater bony fishes

12. Which of the following statements about the essential amino acids is false? a. Most animals have some essential amino acids. b. Ingesting a surplus of one essential amino acid cannot compensate for a shortage of another. c. Legumes, such as beans and peas, supply all eight of the essential amino acids in humans. d. Acetyl groups can be combined with amino groups to produce many of the nonessential amino acids. e. None of the above

13. Which of the following groups of vertebrates is phylogenetically oldest and retains the ancestral type of heart? a. Reptiles b. Amphibians c. Fishes d. Birds e. Mammals

14. Anesthetics and alcohol can permeate the blood-brain barrier because a. they are small molecules. b. they are water-soluble. c. they are lipid-soluble. d. they pass through gated channels. e. there are receptors for them on blood vessels.

14. In vertebrates, exchange of substances between the blood and the interstitial fluid occurs in the a. arteries. b. arterioles. c. capillaries. d. veins. e. venules.

14. Myoblasts a. communicate a muscle fiber's need for more O2. b. lie in a ring around the muscle fibers, absorbing their metabolic waste. c. are embryonic precursors of muscle fibers. d. move through the fibers, providing ATP where it is most needed. e. are phagocytic, watching for and then attacking pathogens in the muscle fiber.

15. Vitamins are essential nutrients for cells because most _______ and cannot be synthesized by the animal itself. a. are used as an energy source b. are used to digest foods c. function as coenzymes or parts of coenzymes d. a and b only e. All of the above

15. Which of the following molecules is most toxic to cells? a. Water b. Sodium chloride c. Ammonia d. Urea e. Uric acid

16. Cells resulting from the second meiotic division a. Sperm b. Spermatogonia c. Spermatids d. Primary spermatocytes e. Secondary spermatocytes

18. How do muscle fibers shorten during contraction? a. Individual protein filaments contract. b. More cross-bridges are formed between filaments. c. Arrays of filaments overlap and slide past arrays of another type. d. Protein filaments coil more tightly. e. Subunits of protein polymers detach themselves from the larger units.

18. People living in impoverished regions, as well as people with alcohol addiction, frequently have a niacin deficiency called a. beriberi. b. kwashiorkor. c. pellagra. d. scurvy. e. rickets.

19. The concept of a tripartite synapse is the idea that a synapse consists not only of pre- and postsynaptic neurons but also of connections from _______. This concept takes into account the _______ at the synapse. a. dendrites; collection of information from neurotransmitters b. axon terminals; release of neurotransmitters c. astrocytes; contact of astrocytes with neuronal elements d. microglia; macrophage activity e. oligodendrocytes; myelination

19. When examining histological sections derived from the testes of male mammals, you come across cells that are connected by cytoplasmic bridges. Which of the following cells have you found? a. Spermatogonia b. Spermatogonia and/or primary spermatocytes c. Secondary spermatocytes and/or spermatids d. Sertoli cells e. Mature sperm

19. Which of the following behaviors results from the adaptation of sensory cells? a. Going into a deep sleep b. Discriminating different colors c. Ignoring your shoes as you walk d. Detecting high-pitched notes e. Detecting sound and light simultaneously

2. In looking at a section through the brain, you see a neuron with a number of shrublike projections extending from one side of the cell body and a single long projection extending from the other side. The shrublike projections are most likely _______, and the single long projection is most likely _______. a. axons; a dendrite b. Purkinje fibers; the axon c. dendrites; the axon d. axon terminals; the postsynaptic process e. presynaptic processes; the axon hillock

2. Which of the following best explains the ability of a frog to jump 20 times its body length, while we humans can jump only 5 times our body length? a. They use more powerful muscles. b. They compress an elastic material in their legs. c. They have better leverage, because their legs are longer relative to their body mass. d. They have a lower center of gravity. e. They have a more aerodynamic shape, allowing better movement through the air.

20. As compared to the circulatory system of most fishes, the circulatory system of adult amphibians has the advantage of a. a four-chambered heart. b. heart metamorphosis. c. a partial separation between pulmonary and systemic circulation. d. a pocket of the gut that serves as an air bladder. e. separation between oxygenated and deoxygenated blood.

20. When animals die, the lack of ATP causes muscles to stiffen in rigor mortis because a. muscles cannot contract without ATP. b. actin and myosin cannot bind without ATP. c. actin and myosin cannot separate without ATP. d. ATP is required for synthesis of protein filaments. e. ATP forms cross-bridges between filaments.

21. Which of the following is the most likely nutritional deficiency in a person showing pernicious anemia but who has a diet high in whole grains? a. Pantothenic acid b. Biotin c. B12 (cobalamin) d. E (tocopherol) e. Folic acid

21. Which of the following statements about the structure of the fish gill is false? a. Afferent vessels bring blood to the gills, whereas efferent vessels take blood away from the gills. b. Exchange of respiratory gases occurs within the lamellae of the gill filaments. c. The efferent and afferent vessels are the countercurrent flow system of the gill. d. The lamellae greatly increase the surface area for gas exchange. e. The opercular flaps enclose the gill chambers.

22. Approximately how many genes code for olfactory receptor proteins in mice? a. 14 b. 120 c. 1,000 d. 10,000 e. An unknown number; this question has never been studied.

22. Which of the following statements about excretion in animals is false? a. Gills and kidneys serve as excretory organs in bony fishes. b. Whereas tadpoles excrete ammonia, adult frogs typically excrete urea. c. Bony fishes retain high concentrations of urea in their extracellular fluids. d. Humans are ureotelic. e. Terrestrial animals convert ammonia to urea or uric acid.

24. At which of the following stages does the secondary oocyte resume meiosis? a. During prenatal development b. At birth c. When it is fertilized d. At menopause e. At puberty

24. Bird and fish respiratory systems are similar in that both a. employ a countercurrent exchanger. b. have air sacs. c. function by means of unidirectional flow of the environmental medium over the gas exchange membranes. d. consist of infoldings of the body. e. All of the above

25. How does tropomyosin control muscle contraction? a. It provides a bridge between actin and myosin. b. It provides a site where ATP can be utilized. c. Changes in its conformation expose actin-myosin binding sites. d. It transmits an electric charge to the filaments. e. Changes in its shape open membrane channels.

26. Binding of a molecule from a pathogen to a receptor initiates a signal transduction pathway. Which of the following represents the correct order of events in this pathway? a. Phosphorylation of NF-B binding of NF-B to the promoter activation of toll-like receptor transcription of defense genes b. Binding of NF-B to the promoter phosphorylation of NF-B activation of toll-like receptor transcription of defense genes c. Activation of toll-like receptor phosphorylation of NF-B binding of NF-B to the promoter transcription of defense genes d. Activation of toll-like receptor binding of NF-B to the promoter phosphorylation of NF-B transcription of defense genes e. Binding of NF-B to the promoter activation of toll-like receptor transcription of defense genes phosphorylation of NF-B

26. When troponin binds calcium, a. it allows tropomyosin to bind actin. b. ion channels open, and sodium rushes into the muscle cells. c. it changes conformation, twisting tropomyosin and exposing the actin-myosin binding site. d. it changes conformation, exposing the ATP binding site and allowing the actin-myosin bond to break. e. it binds to calmodulin and starts a cascade by activating myosin kinase.

27. A strictly vegetarian diet with no vitamin B12 supplements can lead to a. beriberi. b. pellagra. c. pernicious anemia. d. scurvy. e. night blindness.

27. In order to maintain the resting potential of the nerve cell membrane, the sodium‒potassium pump keeps the concentration of a. K+ and Na+ inside the cell lower than in the extracellular fluid. b. Na+ inside the cell greater than outside the cell, and the concentration of K+ inside the cell lower than outside the cell. c. K+ inside the cell greater than in the extracellular fluid, and the concentration of Na+ inside the cell lower than outside the cell. d. Na+ and K+ inside the cell greater than outside the cell. e. negative ions higher inside the cell by pumping negative ions across the membrane.

29. Which part of a mammalian egg is functionally similar to the vitelline envelope of a sea urchin egg? a. Cumulus b. Plasma membrane c. Zona pellucida d. Cytoplasm e. Jelly coat

3. Which anatomical adaptation allows bats to hear the echoes of their high-pitched sound pulses? a. A pit organ in front of their eyes b. Heat-sensing cells surrounding their jaw c. Small muscles that adjust their hearing sensitivity d. Membranes of their wings that vibrate in response to the echoes e. The shape of their ears

30. The rate of gas exchange in mammals is maximized by a. an exceedingly high partial pressure of O2 in the blood. b. the opening of the larynx (voice box) into the trachea. c. an enormous surface area for gas exchange. d. the animals' small increase in size during inhalation. e. the production of mucus and surfactants.

31. Which of the following statements about the heartbeat in mammals is true? a. Only the ventricles contract in unison. b. Only the atria contract in unison. c. The atria contract in unison, and the ventricles contract in unison. d. Only the atrium and ventricle on the right side of the heart contract in unison. e. Only the atrium and ventricle on the left side of the heart contract in unison.

32. Epitopes are a. molecules produced by mast cells. b. produced by clonal selection. c. specific sites on antigens that are recognized by the immune system. d. responsible for immunological tolerance. e. antibodies that were first discovered by Jenner.

32. In the cardiac cycle of humans, blood pressure is at its maximum when the _______ are _______ during _______. a. atria; contracting; systole b. atria; contracting; diastole c. ventricles; contracting; systole d. ventricles; relaxing; systole e. ventricles; relaxing; diastole

32. In which of the following animals is external fertilization relatively common? a. Mammals b. Birds c. Fishes d. Lizards e. Snakes

32. The potassium equilibrium potential is reached when the diffusion of K+ out of the cell due to the concentration gradient is balanced by the movement of K+ into the cell due to the negative electric potential. This potassium equilibrium potential a. is always equivalent to the membrane potential. b. requires the activity of voltage-gated ion channels. c. is due to electrochemical gradients. d. is equivalent to the resting potential. e. was discovered through patch clamping.

33. Compared to humans, dogs have a much more acute sense of smell due to a. the larger amount of mucus in their noses. b. the greater length of their basilar membranes. c. their greater number of olfactory receptors. d. the larger number of capillaries in their noses. e. the typical canine body temperature.

34. In many species of birds, males lack a penis. Which of the following statements about the reproductive process of these birds is true? a. They cannot engage in internal fertilization. b. They deposit sperm packets in the environment, where they are retrieved by a female and utilized to fertilize her eggs. c. They engage in internal fertilization but without an accessory sex organ. d. They engage in indirect sperm transfer. e. Their offspring develop via parthenogenesis.

34. When a female sable antelope smells the urine of a male antelope, a sample of nasal fluid is drawn over chemoreceptors of the _______, which is a structure located on the septum dividing the two nostrils. a. gustatory nucleus b. fovea c. vomeronasal organ d. organ of Corti e. loop of Henle

36. Which of the following is not one of the water conservation adaptations of amphibians living in dry environments? a. Waxy secretions on the skin b. Estivation during dry periods c. Production of concentrated urine d. Burrowing into the ground e. Large urinary bladders

37. According to the clonal selection theory, a. an antibody changes its shape to match the antigen it meets. b. an individual vertebrate contains only one type of B cell. c. an individual vertebrate contains many types of B cells, each producing one kind of antibody. d. each B cell produces many types of antibodies. e. many clones of antiself lymphocytes appear in the bloodstream.

37. Smokers tend to cough frequently because coughing a. releases the tar that fills numerous alveoli. b. is a response to histamine that is released when smoke narrows the airway. c. clears the mucus, which the paralyzed cilia can no longer do. d. assists in release of surfactant, which is inhibited by smoking. e. All of the above

37. Which of the following statements about gustation is true? a. Each type of gustation receptor protein differs in its rate of firing. b. All gustation receptor proteins are metabotropic but differ in the second messenger system they use. c. Gustation receptor proteins release neurotransmitter onto sensory neurons, which conduct the information that will be interpreted as taste. d. All gustation receptor proteins are ionotropic, but differ in the type of ion channel that is opened when stimulated. e. All gustation receptor proteins are similar in their mode of stimulation, but they synapse with different sensory neurons that stimulate different parts of the brain.

38. Fast-twitch skeletal muscle fibers, called white muscle, are characterized by a. a high concentration of myoglobin. b. abundant mitochondria. c. the rapid development of high tension. d. the ability to sustain activity for a long time. e. a higher oxygen requirement than that of slow-twitch fibers.

38. Patch clamping a. fixes a break in a cell membrane. b. records electrical activity inside a cell. c. records ion movements through a single channel. d. records ion movements through an entire nerve. e. records an action potential through a single channel.

38. Which of the following might be a reason for the evolution of basic tastes? a. One food source might be more available than another. b. The ability to detect diverse types of saltiness is important for calorie intake. c. Detecting toxic compounds released by plants allows herbivores to avoid these toxins. d. Microvilli increase the surface area of the taste bud and allow for more complex flavors. e. Taste sensory cells form synapses with dendrites of many different sensory neurons that perceive taste differently.

39. If you were vaccinated against measles as a child, you still have immunity to the disease decades later because a. plasma cells secrete cytokines. b. effector T cells secrete antibodies. c. memory B cells can persist in the body for several decades. d. All of the above e. None of the above

4. The energy content of food is described in terms of calories because a. the amount of energy in food depends on the temperature. b. food heats up as it is being digested. c. the energy in food ultimately becomes mostly heat. d. heat is the main product of digestion. e. heat is the main product of respiration.

4. Which of the following is not transported through a closed circulatory system? a. Heat b. Respiratory gases c. Gametes d. Hormones e. Nutrients

41. The lungs expand in inhalation because a. the diaphragm contracts upward. b. the shoulder girdle moves upward. c. the volume of the thoracic cavity increases. d. lung tissue actively stretches. e. the lung tissue rebounds from exhalation.

41. Which of the following statements about the Pacinian corpuscle is true? a. It adapts slowly and provides information about low-frequency vibrating stimuli. b. It responds to extended, steady pressure. c. It adapts rapidly and provides information about high-frequency vibrating stimuli. d. It has long, extensive dendritic processes. e. It is extremely sensitive to light touch.

42. In this scenario, the conveyor belts and distribution of useful items to other areas are most analogous to the _______ in a digestive system. a. esophagus b. stomach c. intestine d. anus e. crop

42. Two electrodes on either side of the plasma membrane of a resting neuron show a difference of about ‒65 mV. If the value changes quickly to about +50 mV and then rapidly returns to ‒65mV, the most likely explanation is that a. the cell membrane briefly became hyperpolarized. b. a graded potential passed by the electrodes. c. an action potential was triggered due to changes in voltage-gated Na+ and K+ channels. d. voltage-gated Na+ channels closed, causing a spike of depolarization, and then opened again. e. leak K+ channels opened and then closed.

42. Which of the following substances would be reabsorbed in the smallest amounts by the renal tubule? a. Water b. Glucose c. Urea d. Sodium ions e. Amino acids

42. Wild turkeys have breast muscles that are capable of explosively fast flight, but only for short distances. These muscles most likely a. fuel their rapid flight with high levels of mitochondria. b. have surprisingly low rates of ATPase activity. c. are fast-twitch muscles. d. are slow-twitch muscles. e. have substantial reserves of glycogen.

43. All of the following structures are used to grind food into fragments except a. a radula. b. a gizzard. c. a crop. d. a mandible. e. a tooth.

43. Despite their lumbering appearance, alligators are capable of explosively fast running, but only for short distances. This is most likely because their muscles a. fuel their rapid movement with high levels of mitochondria. b. have surprisingly low rates of ATPase activity. c. are fast-twitch muscles. d. are slow-twitch muscles. e. have substantial reserves of glycogen.

44. Each molecule of hemoglobin, when fully saturated, carries _______ molecule(s) of oxygen. a. 1 b. 2 c. 4 d. 20 e. nearly 100

44. If the slow-twitch muscle fiber of a world-class marathon runner, weight lifter, and triathlon competitor (triathlon includes a 5k run, 1k swim, and 10k bike race) were compared, which of the following would represent the correct order, from highest to lowest, of the percentage slow-twitch muscle in their bodies? a. Triathlete, marathon runner, weight lifter b. Weight lifter, marathon runner, triathlete c. Marathon runner, triathlete, weight lifter d. Triathlete, weight lifter, marathon runner e. Marathon runner, weight lifter, triathlete

44. Which of the following statements about mechanoreceptors is false? a. Mechanoreceptors transduce mechanical forces into changes in receptor potential. b. If a mechanoreceptor is subject to increased distortion, more ion channels within its membrane open. c. Most mechanoreceptors are metabotropic sensory receptors. d. If the receptor potential of a mechanoreceptor rises above a threshold, an action potential is propagated. e. Stimulus strength determines the rate of generated action potentials.

44. Which of the following statements about the tubular digestive tract of animals is false? a. Food is digested extracellularly. b. There are two openings to the digestive tract. c. Food must always be broken into smaller pieces before ingestion. d. All digestion occurs inside the digestive tract. e. The digestive tract has specialized segments.

45. In women, the hematocrit, or percentage of the blood made up of red blood cells, is about _______ percent. a. 10 b. 25 c. 42 d. 70 e. 90

47. During urine formation in the vertebrate kidney, the processes of filtration and tubular secretion are similar in that both a. involve substances moving from the filtrate into the blood. b. rely on pressure differences. c. involve substances moving from the blood into the filtrate. d. rely on active transport. e. occur at Bowman's capsule.

47. In placental mammals, the blastocyst normally implants within the a. oviducts. b. ovary. c. endometrium of the uterus. d. myometrium of the vagina. e. chorion.

48. Which of the following is involved with the inflammatory response and is found bound to mast cells? a. IgA b. IgD c. IgE d. IgG e. IgM

49. Which of the following structures plays an increasing role in urination as toddlers develop? a. Smooth muscle sphincter at the base of the urethra b. Ureters c. Skeletal muscle sphincter at the base of the urethra d. Urethra e. Urinary bladder

5. A scientist wishing to study a vertebrate animal that is an osmoconformer might choose a study species from which of the following groups? a. Marine bony fishes b. Marine mammals c. Marine cartilaginous fishes (sharks and rays) d. Birds e. Freshwater bony fishes

5. Which of the following is generally restricted to the vessels and heart in a closed circulatory system? a. Platelets b. White blood cells c. Red blood cells d. Neutrophils e. Macrophages

52. Which of the following statements about myoglobin is false? a. Iron in the myoglobin molecule can bind to O2. b. Myoglobin is found in muscle cells. c. Myoglobin has a lower affinity for O2 than hemoglobin does. d. Diving mammals have high concentrations of myoglobin in their muscles. e. Skeletal muscles can differ in their myoglobin content.

53. If the proteins that anchor acetylcholine-containing vesicles to the presynaptic membrane are damaged by botulism toxins, what effect will this have on the neuromuscular junction? a. Reuptake by the presynaptic membrane will be impaired. b. An action potential will not be able to open voltage-gated Ca2+ channels. c. Neurotransmitter will not be released into the synaptic cleft. d. Graded potentials will cause fusion of the vesicles with the cell membrane. e. Endocytosis of acetylcholinesterase will be impaired.

53. Satellite cells are characterized in part by their ability to a. communicate a muscle fiber's need for more O2. b. lie in a ring around the muscle fibers, absorbing their metabolic waste. c. produce new muscle fibers. d. move through the fibers, providing ATP where it is most needed. e. phagocytize, watching for and then attacking pathogens in the muscle fiber.

53. Which of the following represents the principal difference between the uterine cycle of humans and the cycles of other mammals? a. The uterine cycles of other mammals occur if fertilization occurs, whereas the uterine cycle of humans occurs if fertilization does not occur. b. The uterine cycle of humans occurs if fertilization occurs, whereas the uterine cycles of most mammals occur if fertilization does not occur. c. The uterine cycles of most other mammals lack menstruation. d. The uterine cycles of most other mammals lack induced ovulation. e. Peaks of progesterone in the uterine cycles of most other mammals correspond to periods of enhanced sexual receptivity referred to as "heat."

54. A platelet is activated to initiate clotting a. during a histamine reaction. b. when leukocytes are activated. c. when it encounters collagen fibers. d. when blood flow rates drop. e. in the presence of prothrombin.

54. To test whether a group of hair cells depolarizes in response to a specific frequency, a researcher could produce the sound and then measure a. the rate of action potentials in the hair cells. b. the flexion of the basilar membrane. c. the membrane potentials of the hair cells. d. vibration in the tympanic membrane. e. pressure waves transduced by the organ of Corti.

55. The inactive form of stomach enzymes is activated by a. enterokinase. b. ATP. c. low pH. d. the appropriate substrate molecule. e. the presence of water.

56. In the stomach, pepsin activates pepsinogen molecules in a positive feedback process called a. emulsification. b. absorption. c. autocatalysis. d. rumination. e. excretion.

56. Which of the following sensory structures provides mammals with information about the position and orientation of the head? a. Eustachian tube b. Cochlea c. Semicircular canal d. Oval window e. Tympanic membrane

57. Blood is at its lowest pressure in the a. arteries. b. arterioles. c. capillaries. d. venules. e. veins.

57. Which of the following would result from the inhibition of acetylcholinesterase? a. Release of neurotransmitter from the presynaptic membrane would be inhibited. b. Synthesis of neurotransmitter in cells would be inhibited. c. Breakdown of neurotransmitter in the synapse would be inhibited. d. Stimulation of the postsynaptic membrane would be inhibited. e. Cholinergic receptors would be inhibited.

59. After the first 15 minutes of a 10-km run, the major energy requirements of the leg muscles are supplied by a. preformed ATP. b. glycolysis. c. oxidative metabolism. d. pyruvate and lactate. e. the high-protein drink consumed right before the race.

59. In a visual system, light is absorbed by rhodopsin, which causes a. a change of shape in opsin, a photosensitive protein. b. depolarization of the rhodopsin molecule, which results in the generation of an action potential. c. first a change in the retinal molecule into a different isomer, and then a change in shape of the opsin protein. d. oxidation of the rhodopsin molecule, a process known as bleaching. e. None of the above

59. The filtrate flows through the _______ immediately before entering a collecting duct. a. Renal pyramid b. Proximal convoluted tubule c. Distal convoluted tubule d. Loop of Henle e. Collecting duct

59. Which of the following statements about digestion in the small intestine is false? a. Most digestion occurs in the duodenum of the small intestine. b. Fat in the small intestine is emulsified by bile that is produced by the liver and stored in the gallbladder. c. Bile molecules in the small intestine have one end that is lipophobic and one end that is hydrophilic. d. The pancreas secretes zymogens and bicarbonate ions into the duodenum of the small intestine. e. Enterokinase is secreted by intestinal mucosal cells.

60. (Small diameter) × (very large number) = the reason that _______ are the blood vessels with more total cross-sectional area than the other blood vessels listed. a. arteries b. arterioles c. capillaries d. venules e. veins

60. Which of the following statements about BPG is false? a. It results from metabolism of glucose. b. It stands for 2,3-bisphosphoglyceric acid. c. It causes a left-shifted O2-binding/dissociation curve in adult hemoglobin. d. Its production increases with altitude. e. Its production increases with exercise.

60. Which of the following statements about the summation of postsynaptic potentials is false? a. Summation typically takes place in the axon hillock. b. It is the major mechanism for integrating information within the nervous system. c. A neuron receives only excitatory or inhibitory input, but not both. d. Temporal summation adds up potentials generated at the same site in rapid succession. e. Spatial summation adds up potentials generated simultaneously at different sites on the cell.

61. Most of the CO2 in the blood is transported as _______, and it is located mainly in the _______. a. CO2; plasma b. H2CO3; plasma c. HCO3-; plasma d. carboxyhemoglobin; erythrocytes e. HCO3-; erythrocytes

62. Pregnancy tests detect the presence of a. luteinizing hormone. b. follicle-stimulating hormone. c. human chorionic gonadotropin. d. estrogen. e. progesterone.

62. The loops of Henle functions as a countercurrent multiplier mechanism. In this context, "countercurrent" refers to the flow of filtrate in opposite directions in the descending and ascending limbs of the Loop of Henle, and "multiplier" refers to the a. different permeabilities of the descending and ascending limbs. b. amount of water conserved as a multiple of the length of the loop. c. creation of a solute concentration gradient in the interstitial fluids of the medulla. d. increasing concentration of filtrate as it flows through the loop. e. process by which active transport in the descending and ascending limbs multiplies the concentration gradient within the filtrate.

64. To bring distant objects into focus, mammals and birds a. contract ciliary muscles to make the lens more round. b. relax suspensory ligaments attached to the lens. c. alter lens shape by relaxing ciliary muscles. d. alter lens shape by moving the lens closer to the retina. e. alter lens shape by moving the lens farther from the retina.

65. Neural control of breathing is a function of the a. cerebrum. b. diaphragm. c. medulla. d. olfactory lobe. e. spinal cord.

66. Emergency Medical Technicians (EMTs) suspect that a victim of a serious accident has suffered an injury to the brainstem because his breathing has continued but is irregular. Specifically, the injury is likely to a. be limited to the spinal cord. b. have destroyed the medulla. c. be at a level above the medulla. d. be between the pons and medulla. e. have severed the spinal cord in the neck.

67. A woman has learned that her fetus has a major birth defect that will lead to death shortly after birth. Medical termination of her pregnancy is called a. a miscarriage. b. assisted reproductive technology. c. a therapeutic abortion. d. an abortion for fertility control. e. a spontaneous abortion.

68. For women, the earliest stage in the reproductive process targeted by most methods of birth control is _______ and the latest stage is _______. a. oogenesis; fertilization b. fertilization; implantation c. ovulation; implantation d. oogenesis; implantation e. ovulation; fertilization

68. Which of the following physiological responses would not correct for a drop in glomerular blood pressure? a. Elevation of the body's central blood pressure by angiotensin b. Stimulation of thirst in the brain by angiotensin c. Constriction of the afferent renal arterioles d. Constriction of the efferent renal arterioles e. Stimulation of aldosterone release by the adrenal cortex

68. Why is it easier to see a small object in dim light condition if you turn your head slightly? a. Visual acuity occurs in the outer area of the eye. b. The fovea is better able to focus in that position. c. Rods contribute more to night vision and are located in the periphery. d. The center of the visual field is less sensitive in the dark. e. Humans have two foveas and the lateral one has higher acuity.

69. Which of the following is the most likely to be a delayed hypersensitivity reaction to an allergen? a. Sneezing from ragweed exposure b. Production of IgE by mast cells c. Rash after exposure to poison oak d. Production of IgG by T-helper cells e. Difficulty breathing after being stung by a bee

7. If the ion flow into a cell increases with the temperature of the extracellular fluid, the plasma membrane most likely contains a. electrosensors. b. mechanoreceptors. c. thermoreceptors. d. chemoreceptors. e. photoreceptors.

7. Organisms that are ionic regulators maintain their extracellular fluids at an _______ concentration that _______ that of the environment. a. osmotic; is lower than b. osmotic; is the same as c. ion; may differ from d. ion; is the same as e. osmotic; is higher than

7. The area where a neuron comes extremely close to a target cell and transmits information to the target cell is a. the ganglion. b. the axon hillock. c. a synapse. d. the nodes of Ranvier. e. insulated with myelin.

70. A woman wishing to prevent pregnancy and to avoid sexually transmitted diseases should choose which of the following methods of birth control? a. Diaphragm b. Cervical cap c. Condom d. IUD e. Birth control pill

70. C. R. Bainton conducted an experiment in which he increased the workload of dogs by having them run on inclined treadmills and showed that respiratory rate responded to CO2 levels. However, this success story followed an earlier experiment that did not support his hypothesis. In the earlier study, he a. compared respiratory rate of dogs versus cats. b. compared sleeping versus barking dogs. c. changed the speed at which the dogs ran. d. changed the dog's motivation by keeping them food-stressed. e. injected dissolved O2 into the dogs' arteries.

70. When you read this question and eventually mark an answer, your neurons busily send information to and from your brain, and compare it against what you learned in class. Coordination of these processes is supplied by a. afferent neurons. b. efferent neurons. c. interneurons. d. glial cells. e. None of the above

71. Which of the following is not one of the risk factors for developing atherosclerosis? a. A high-fat diet b. Smoking c. Living at a high altitude d. An inactive lifestyle e. Hypertension

71. _______ in the hypothalamus stimulate release of antidiuretic hormone (ADH), and _______ in the aorta and carotid arteries inhibit release of ADH. a. Angiotensin receptors; stretch receptors b. Stretch receptors; chemoreceptors c. Osmoreceptors; stretch receptors d. Renin receptors; chemoreceptors e. Stretch receptors; osmoreceptors

72. The breathing center in humans initiates ventilation in response to a. a decrease in air pressure. b. a decrease in O2. c. an increase in CO2. d. the time since the last breath. e. the rate of gas exchange in the alveoli.

72. When a piece of thrombus breaks loose and lodges in a smaller vessel, blocking the flow of blood, the result is a. thrombosis. b. an infarction. c. an embolism. d. atherosclerosis. e. a hematocrit.

73. Which of the following statements about the knee-jerk reflex is true? a. It requires a decision to move the leg. b. It requires stretch receptors that fire action potentials in motor neurons. c. It involves motor neurons conducting action potentials to the leg muscles. d. It requires interneurons carrying signals to the brain. e. It involves output leaving the dorsal horn of the spinal cord.

74. With reference to the circulatory system, what does the acronym MAP stand for? a. Monoadenosine phosphate b. Main arterial pathways c. Mean arterial pressure d. Minor anterior pillus e. Moderate albumen production

75. Following a vasectomy, a. there is a decrease in testosterone production in the male. b. sperm are no longer produced. c. sperm cannot reach the urethra and are reabsorbed. d. males experience decreased sexual response. e. All of the above

77. Which of the following statements concerning lipoproteins is true? a. Low-density lipoproteins (LDLs) contain more cholesterol than high-density lipoproteins (HDLs). b. LDLs carry cholesterol from the tissues to the liver. c. Exercise raises a person's HDL levels. d. High HDL levels are considered a risk for cardiovascular disease. e. High LDL levels are considered an indication of good cardiovascular health.

78. Precapillary sphincters are able to a. increase blood pressure to the arteries. b. decrease blood pressure to the veins. c. shut off the supply of blood to the capillary bed. d. increase blood pressure to the capillaries. e. provide blood to smooth muscles surrounding capillary beds.

78. Which of the following methods of contraception would a physician most likely recommend to a young female patient who has tested positive for the sexually transmitted disease genital herpes? a. Tubal ligation b. Combination estrogen and progesterone birth control pill c. Condom d. Intrauterine device e. Spermicidal jelly

8. Which muscle type is multinucleated? a. Smooth b. Cardiac c. Skeletal d. Both a and b e. All of the above

80. Insulin is released by the pancreas when blood levels of a. glucose fall. b. glucagon fall. c. glucose rise. d. glucagon rise. e. secretin fall.

84. In humans, long bones begin as _______ bones. At maturity, the shaft of a long bone consists of a _______ of primarily _______ bone. a. dermal; cylinder; compact b. dermal; solid rod; cancellous c. cartilage; cylinder; compact d. cartilage; cylinder; cancellous e. cartilage; solid rod; compact

9. The sexual role assumed during courtship by an individual of the parthenogenetic whiptail lizard species Cnemidophorus uniparens a. depends on its testosterone levels. b. determines whether it will produce sperm. c. depends on its current stage in the ovarian cycle. d. determines whether it will fertilize its mate's eggs. e. is determined at birth.

93. When you open a typical textbook, the pages rotate around the binding as if it were a body joint. Which type of joint does it most resemble? a. Ball-and-socket b. Pivot c. Hinge d. Saddle e. Plane

95. Automatic doors require a motor that pushes a rod that opens the door; the door is held in place by a hinge and a doorframe, and a separate controller pulls the door back to the closed position. The rod pushing open the doorframe is most analogous to a. tendons. b. ligaments. c. extensors. d. flexors. e. None of the above

10. Which of the following is not one of the advantages of closed circulatory systems as compared to open systems? a. Closed systems move wastes and nutrients to and from tissues more quickly. b. In closed systems, molecules specialized as carriers of hormones and nutrients can be isolated to vessels before being delivered to tissues. c. As certain tissues experience a greater need for respiratory gases, closed systems can more precisely prioritize the delivery of gases to them. d. In hermaphroditic species, closed systems can deliver gametes from one set of sex organs directly to the other. e. As certain tissues experience a greater need for nutrients, closed systems can more precisely prioritize the delivery of nutrients to them.

10. Which of the following statements about receptor potentials is false? a. They can cause the release of a neurotransmitter. b. They can cause an action potential. c. They are a change in membrane potential of the sensory cell. d. They can spread over long distances. e. They can be amplified.

11. Most animals digest dietary proteins into their constituent amino acids and then synthesize new proteins because a. macromolecules like proteins cannot be readily transported through cell membranes. b. protein structure and function are highly species-specific. c. foreign proteins are considered invaders and are attacked by the immune system. d. a, b, and c e. None of the above

11. Which of the following supports the hypothesis that you are undergoing an adaptive immune response after exposure to a pathogen? a. An increase in lysozyme production b. Inflammation at the site of exposure c. Increased flow of mucus d. Recognition of infected cells by T cells e. Phagocytosis of the pathogen is observed

12. How can arthropods maintain a high metabolism in the absence of a closed circulatory system? a. In species with wings, the beating of the wings moves air across their tissues, thus acting analogously to a heart pumping blood through vessels. b. They do not use their circulatory systems for gas exchange. c. Some, such as crabs, have vessel systems that transport fluid from one part of the body to another. d. Both b and c e. None of the above

12. In a thin section through brain tissue you see a cell that is wrapped around the axon of a neuron, forming concentric layers of plasma membrane. This cell most likely a. is part of the blood‒brain barrier. b. supplies nutrients to neurons. c. gives structural support to the axon. d. insulates the axon for rapid conduction of action potentials. e. recycles neurotransmitter in the synapses.

12. One reason rapid gas exchange can be accomplished more easily in air than in water is that a. the O2 content of water is higher than that of air. b. the CO2 content of water is higher than that of air. c. O2 diffuses more rapidly in water than in air. d. water is more dense and viscous than air. e. more energy is required to move air than to move water.

12. Reproduction in the parthenogenetic whiptail lizard species, Cnemidophorus uniparens, requires sexual behavior, but the species is all female. How do these lizards reproduce? a. Females hybridize with males of a related species, but accept only some of the chromosomes in the sperm. b. Females that are the most fit become males temporarily, produce and transfer sperm to other females, and then revert to being females. c. The least fit females become males temporarily, produce and transfer sperm to other females, and then revert to being female. d. Females with high progesterone levels act like males, but they do not produce any sperm. e. Females with high estrogen levels act like males, but they do not produce any sperm.

14. Adventurers attempting to recreate the Polynesians' months- or years-long trips across the ocean would likely carry limes with them to avoid the ascorbic acid deficiency called a. beriberi. b. kwashiorkor. c. pellagra. d. scurvy. e. rickets.

14. Since all sensory systems process information as action potentials, how are different stimuli recognized as different sensations? a. The strength of the stimulus determines how it is interpreted by the central nervous system. b. Action potentials are combined in the brain. c. Sensory cells respond to only one type of stimulus. d. Action potentials arrive at different parts of the central nervous system. e. The strength of the stimulus determines the type of sensation.

15. Humans often have difficulty breathing at high elevations because the _______ than it is at low elevations. a. percentage of O2 in the air is lower b. temperature is lower c. barometric pressure is higher d. partial pressure of O2 is lower e. air is drier

16. An ice cube placed on your hand will cause some cells to fire action potentials more frequently and other cells to reduce the number fired. What explains the different responses? a. Thermoreceptors will detect the cold and slow down the rate of firing. b. A pressure-sensitive channel will increase its firing rate due to the weight of the ice cube. c. Some sensory cells will interpret the ice cube as painful and slow down their firing rate. d. Your hand has more than one type of receptor cell, and these can change their firing rates in response to a new stimulus. e. Only the receptors that the ice cube actually touches will slow down their firing rate.

16. Which of the following statements about the structure of skeletal muscle is true? a. The light bands of the sarcomere are the regions where actin and myosin filaments overlap. b. When a muscle contracts, the A bands of the sarcomere lengthen. c. The myosin filaments are anchored in the Z lines. d. When a muscle contracts, the H zone of the sarcomere shortens. e. The sarcoplasm of the muscle cell is contained within the sarcoplasmic reticulum.

17. Which of the following statements about the molecular arrangement of actin and myosin in myofibrils is false? a. A thin filament consists of actin and tropomyosin. b. Two chains of actin monomers are twisted into a helix. c. Two strands of tropomyosin lie in the grooves of the actin. d. Troponin forms the head of the myosin molecule. e. The myosin heads have ATPase activity and interact with the actin.

18. Astrocytes influence the connectivity between a pre- and postsynaptic neuron by a. causing additional storage of glycogen within neurons, thereby increasing their metabolism. b. increasing myelination of neurons, which results in faster action potentials. c. decreasing the permeability of blood vessels, thereby aiding in the supply of nutrients to neurons. d. taking up and releasing neurotransmitters and therefore altering the activity of neurons. e. conducting action potentials, which increase the flow of information.

18. Many bacteria and fungi typically live and reproduce on the skin without causing disease. Therefore, they can be considered a. microcytes. b. ectocytes. c. pathogens. d. normal flora. e. normal fauna.

19. Primates should eat citrus fruit to prevent scurvy, which is due to a deficiency of a. niacin. b. thiamin. c. calciferol. d. ascorbic acid. e. biotin.

19. You are a physician and a patient presents with pain in his big toe. His diet includes significant amounts of caffeine and nucleic acids. You suspect gout and draw fluid from the inflamed joint. The presence of which of the following would help confirm your diagnosis? a. Carbon dioxide b. Water c. Ammonia d. Uric acid e. Urea

2. The main advantage of communicating by means of extremely low-frequency sound waves is that a. it permits coordination of attacks on prey. b. the echoes of these waves help in navigation. c. the sound travels in fast pulses. d. far-ranging animals can hear the sounds over distances. e. only the same species can detect the sound.

21. Chemoreceptors a. respond to chemical stimuli. b. can cause strong behavioral responses. c. do not undergo adaptation. d. Both a and b e. All of the above

23. Approximately what percentage of the mouse genome codes for olfactory receptor proteins? a. 0.03 percent b. 0.13 percent c. 0.3 percent d. 3.0 percent e. 30 percent

23. Which of the following is not one of the major ions that carry electrical charges across the plasma membranes of neurons? a. Sodium (Na+) b. Potassium (K+) c. Calcium (Ca2+) d. Magnesium (Mg2+) e. Chloride (Cl‒)

24. Which of the following statements about protonephridia in a freshwater flatworm is false? a. A protonephridium consists of a flame cell and tubule. b. Extracellular fluid moves into a protonephridium because pressure is lower inside the tubule than it is outside of it. c. Tubule cells reabsorb solutes. d. Fewer ions are reabsorbed than secreted. e. Filtrate flows out the excretory pore.

24. Which of the following statements about the complement system is false? a. It consists of more than 20 different proteins. b. It is involved in a cascade of reactions. c. It lyses invading cells. d. It consists of highly folded membranes that capture pathogens. e. It interacts with phagocytes.

26. In the respiratory cycle of birds, air flows through the trachea, to the bronchi, and then a. into the parabronchi. b. back through the trachea. c. to the air capillaries. d. into the posterior air sacs. e. into the anterior air sacs.

27. In humans, oxygenated blood is transported from the lung to the heart by the a. pulmonary artery. b. inferior vena cava. c. superior vena cava. d. pulmonary vein. e. coronary artery.

27. Which of the following are chemoreceptors? a. Stretch receptors b. Hair cells c. Pressure receptors d. Olfactory receptors e. Ligands

28. The sodium-potassium pump in neurons a. requires ATP to work. b. moves potassium ions to the inside of the neuron and sodium ions to the outside. c. works against a concentration gradient. d. All of the above e. None of the above

28. Tidal breathing decreases the efficiency of gas exchange in organisms such as mammals for a number of reasons. Which of the following is not one of those reasons? a. The absence of countercurrent gas exchange b. The existence of dead space in the airways c. The residual volume of the lungs d. A short diffusion path length e. The limit in the O2 concentration gradient between air and blood

3. Which of the following statements about the filtration process of the excretory systems of animals with closed circulatory systems is false? a. The filter consists of walls of capillaries and associated tubules. b. It is driven by blood pressure. c. It produces filtrate without large molecules. d. It processes filtrate by moving valuable solutes back into blood. e. It produces filtrate that does not contain cells.

30. Fertilization in mammals and sea urchins is similar in which of the following ways? a. The first structure surrounding the egg with which the sperm comes in contact triggers the acrosomal reaction. b. It occurs in the external environment. c. Sperm recognition molecules occur on the egg plasma membrane. d. Rises in calcium in the cytoplasm prevent entry by additional sperm. e. The fast block to polyspermy occurs when a sperm contacts the egg plasma membrane.

30. Which of the following statements about Malpighian tubules is false? a. They make up the excretory system of insects. b. An individual organism may have from 2 to 100 Malpighian tubules. c. They empty into the gut. d. They filter nitrogenous wastes by means of a pressure gradient. e. They rely on active transport.

33. Which of the following groups of vertebrates includes some species that display internal fertilization without copulation? a. Bony fishes b. Cartilaginous fishes c. Frogs d. Salamanders e. Birds

34. Surfactant produced by cells lining the alveoli serves to a. increase surface tension. b. increase stretching of the alveolar walls. c. assist muscular movements of breathing. d. reduce cohesion of surface molecules. e. reduce ciliary movement.

35. Cartilaginous fishes maintain an osmotic concentration in their interstitial fluids that matches that of seawater by a. excreting large amounts of water. b. drinking large amounts of seawater. c. concentrating salts in their blood. d. concentrating urea in their tissue fluids. e. excreting salts at their gills.

35. Muscle tone is the condition in which a. different muscles are taking responsibility for maintaining posture. b. the muscle has generated maximum tension. c. the muscle will eventually exhaust its supply of ATP. d. a small but changing number of motor units are active. e. the maximum number of action potentials is being received by the muscle.

36. The extraordinary diversity of antibodies results in part from a. the action of monoclonal antibodies. b. the splicing of protein molecules. c. the action of cytotoxic T cells. d. the rearrangement of genes. e. their remarkable nonspecificity.

36. Which of the following is not a carnivorous feeding adaptation? a. A spiderweb b. Rattlesnake venom c. Bat echolocation d. An elephant's trunk e. A jellyfish tentacle

36. Which of the following represents one similarity between fast- and slow-twitch muscle fibers? a. Number of mitochondria b. Amount of myoglobin c. Amount of glycogen and fat d. Number of neuromuscular junctions e. Level of ATPase activity

36. Which of the following statements about gustation is false? a. Taste receptors may be either ionotropic or metabotropic. b. All stimulated taste sensory neurons respond by generating an action potential. c. Microvilli increase the surface area of taste sensory cells. d. Individual taste bud cells are replaced every few months. e. Taste sensory cells form synapses with dendrites of sensory neurons.

37. The skeletal muscles in the legs of competitive cross-country skiers and long-distance runners are likely to have a. almost all slow-twitch fibers. b. almost all fast-twitch fibers. c. about the same number of slow-twitch and fast-twitch fibers. d. more slow-twitch fibers. e. more fast-twitch fibers.

39. If Na+ channels open and sodium ions diffuse into the cell, a. the cell will become hyperpolarized. b. other sodium ions will move out of the cell. c. voltage-gated channels will remain closed. d. the inside of the cell will become less negative. e. action potentials will be triggered.

39. The heart beats because of cardiac muscle's unique properties, such as a. high resistance to outside stimulation. b. an external pacemaking system. c. a low level of electrical activity. d. cell communication via gap junctions. e. rapid communication through release of neurotransmitters between cells.

39. Which of the following anatomical features is shared by both the reproductive and excretory systems in most male mammals? a. Prostate gland b. Seminiferous tubules c. Vas deferens d. Urethra e. Epididymis

40. When voltage-gated K+ channels open in the cell membrane of a neuron, K+ moves a. into the cell, and the membrane becomes hyperpolarized. b. into the cell, and the membrane becomes depolarized. c. out of the cell, and the membrane becomes depolarized. d. out of the cell, and the membrane becomes hyperpolarized. e. through the leak channels and opens leak channels for Na+.

41. Which of the following statements concerning graded potentials is true? a. They are equivalent to the resting potential of the cell membrane. b. They travel long distances in order to generate an action potential. c. They are important in all sensory systems except neuromuscular junctions. d. They allow a cell to integrate inputs and respond proportionally. e. They are caused by ionic currents spreading over long distances.

42. Compared to the secondary immune response, the primary immune response is _______ powerful and lasts _______ amount of time. a. more; a longer b. more; a shorter c. more; the same d. less; a shorter e. less; a longer

43. A complete blockage in the vas deferens at the end closest to the testis would cause newly matured sperm to remain in the a. seminiferous tubules. b. urethra. c. lumens of the seminiferous tubules. d. epididymis. e. vas deferens.

44. In the electrocardiogram (ECG) of a normal cardiac cycle, the wave called T corresponds to _______ of the _______. a. depolarization; atria b. depolarization; ventricles c. repolarization; atria d. repolarization; ventricles e. Both a and b

45. Which of the following statements about fast-twitch and slow-twitch fibers is false? a. In skeletal muscle, the most important factor determining the proportion of fast- and slow-twitch fibers is genetic heritage. b. Aerobic training increases the oxidative capacity of intermediate fibers. c. A single muscle may contain fast- and slow-twitch fibers. d. Fast-twitch fibers fatigue slowly. e. Champion sprinters are likely to have a high-proportion of fast-twitch fibers in their legs.

45. Which of the following structures does not serve to increase surface area for nutrient absorption? a. A human's intestinal villi b. An earthworm's infolding of the intestinal wall c. A shark's spiral valve d. A bird's gizzard e. A human's intestinal microvilli

46. Antigens can bind to an antibody at _______ site(s); binding occurs at the _______ regions of the antibody. a. one; constant b. one; variable c. one; specific d. two; variable e. two; constant

46. In mammals, the egg is propelled through the oviduct by means of a. cilia on the surface of the egg. b. the egg's flagellum. c. uterine contractions. d. cilia lining the oviduct. e. amoeboid motion.

46. Which of the following statements about the binding of oxygen by hemoglobin is false? a. The percentage of completely O2-saturated hemoglobin increases as PO2 increases. b. The oxygen-binding curve is S-shaped. c. There is a narrow range of the O2-binding curve where O2 dissociation-association is rapid. d. A very low PO2 is required for all four hemoglobin subunits to bind to O2. e. If one subunit of completely O2-saturated hemoglobin loses its O2, the affinity of the remaining subunits for their O2 increases.

46. Which of the following statements concerning action potentials is true? a. The magnitude of an action potential along an axon is the same, regardless of where it is measured. b. Action potentials travel more quickly in small axons than in large axons. c. Action potentials are conducted without loss of signal. d. Both a and c e. All of the above

48. Bricklayers periodically need to carry heavy stacks of bricks from their truck to the work site, and they are quickly fatigued by this activity. An examination of the muscles used to perform this work would reveal a. substantial fuel reserves. b. low levels of ATPase activity. c. an abundance of blood vessels. d. relatively few mitochondria. e. relatively high amounts of myoglobin.

48. Carbon monoxide (CO) a. binds to hemoglobin with a higher affinity than O2 does. b. may be released by faulty furnaces or the burning of charcoal or kerosene in unventilated areas. c. exposure may cause death from lack of O2. d. a, b, and c e. None of the above

48. The gut of a vertebrate is often described as an elongated tube consisting of four layers of different cell types. Which of the following represents the correct order of those layers, from innermost (lumen-facing) to outermost? a. Submucosa, cartilage, mucosa, endoplasmic reticulum b. Smooth muscle layers, submucosa, mucosa, cartilage c. Cartilage, smooth muscle layers, mucosa, circular muscle d. Mucosa, submucosa, circular muscle, longitudinal muscle e. Cartilage, mucosa, endoplasmic reticulum, submucosa

49. Shot-putters competing in track and field events rely on short, intense bursts of energy, and they are quickly fatigued by the activity. An examination of the muscles used in this sport would reveal a. substantial fuel reserves. b. low levels of ATPase activity. c. an abundance of blood vessels. d. relatively few mitochondria. e. relatively high amounts of myoglobin.

49. Which of the following statements about blood cells is false? a. The body contains at least 500 times more red blood cells than white blood cells. b. Erythrocytes are anucleate in mammals. c. The biconcave shape of the erythrocyte creates a large surface area for gas exchange. d. Red blood cells are generated by stem cells in the spleen. e. Leukocytes destroy foreign cells.

5. Which of the following animals has an open circulatory system? a. Bat b. Earthworm c. Jellyfish d. Crab e. Lizard

5. Which of the following statements about asexual reproduction is false? a. It does not involve meiosis or fertilization. b. It allows all members of a population to convert resources into offspring. c. It allows single individuals to produce offspring. d. It allows for the generation of genetic diversity in changing environments. e. It involves no energy expenditure for mating.

50. The hormone erythropoietin is released by the kidney a. to remove old red blood cells from circulation. b. in response to high levels of oxygen in circulation. c. in response to low levels of hemoglobin. d. to stimulate production of red blood cells. e. to stimulate platelet formation.

50. Which of the following statements about movement of food in the gut is false? a. Three sphincters are found in the vertebrate gut. b. Peristalsis can move food in both directions. c. Stretched smooth muscle contracts. d. Peristalsis begins when food enters the glottis. e. The muscle in a sphincter is normally contracted.

51. While studying histological sections of a mammalian kidney, you come across a slide labeled "inner medulla." Which of the following structures might you see on this slide? a. Bowman's capsule b. Proximal convoluted tubule c. Glomerulus d. Loop of Henle e. Distal convoluted tubule

52. In a human, which of the following is a possible result of damage to the basal end of the basilar membrane? a. Temporal deafness b. Conduction deafness c. Failure of the tympanic window to conduct sound waves d. Inability to detect high-frequency sounds e. Inability to detect low-frequency sounds

53. If the O2-binding curves were plotted for the following molecules, which curve would be to the left of all the others? a. Fetal human hemoglobin b. Adult human hemoglobin in a person exercising heavily c. Adult human hemoglobin in a person at rest d. Myoglobin e. Adult human hemoglobin in a person exercising at high altitudes

53. The major enzyme produced by the stomach is a. amylase. b. chyme. c. hydrochloric acid (HCl). d. pepsin. e. trypsin.

54. A B cell produces IgM molecules that recognize an antigenic determinant on an influenza virus. After several days, the cell begins to produce IgG molecules that recognize the same antigenic determinant. This process is called a. activation. b. RNA splicing. c. gene mutation. d. class switching. e. autoimmunity.

54. Which of the following statements about the acetylcholine receptor is false? a. It is an ionotropic receptor. b. It is a protein. c. Binding of the neurotransmitter allows ion movement across the cell membrane. d. It is found in the presynaptic cell membrane of a neuromuscular junction. e. Acetylcholine binds to the receptor, opening the channel to sodium ions.

55. If the O2-binding curves were plotted for adult hemoglobin under the following conditions, which curve would be to the right of all the others? a. pH 7.6, little 2,3-bisphosphoglyceric acid b. pH 7.6, much 2,3-bisphosphoglyceric acid c. pH 7.2, little 2,3-bisphosphoglyceric acid d. pH 7.2, much 2,3-bisphosphoglyceric acid e. pH 7.4, little 2,3-bisphosphoglyceric acid

55. Normally the acetylcholine receptor‒mediated channel in the motor end plate at a neuromuscular junction is closed. Which of the following statements about this channel is true? a. The channel opens when acetylcholine passes through it. b. The binding of acetylcholinesterase opens the channel. c. Activation of the channel by the binding of acetylcholine causes Na+ ions to enter the presynaptic cell. d. When the channel opens, Na+ ions enter the muscle cell. e. When the channel opens, the cytoplasm of the cell becomes more negative.

55. What is the physiological basis for the auditory system's ability to distinguish different sound frequencies? a. The three bones of the middle ear respond differentially. b. The loops of the semicircular canals respond differentially. c. The oval window and round window respond differentially. d. Different sections of the basilar membrane respond differentially. e. Individual hair cells have different peak frequency responses.

57. The length of the _______ relative to overall kidney size indicates potential maximum urine concentration. a. Renal pyramid b. Proximal convoluted tubule c. Distal convoluted tubule d. Loop of Henle e. Collecting duct

57. Which of the following represents a major difference between strength training and aerobic exercise? a. Only strength training increases endurance by creating more muscle fibers. b. Only aerobic exercise increases the size of muscle fibers. c. Only strength training increases the production of myoglobin. d. Only aerobic exercise increases the oxidative capacity of muscles. e. Only strength training increases the density of capillaries delivering oxygen to the muscles.

58. In mammals, the semicircular canals of the vestibular system participate in responses to changes in position and movement of the head. Which of the following statements about the semicircular canals is true? a. The sensory structures in the semicircular canals allow the mammal to sense position relative to gravity. b. The semicircular canals have openings to the external environment. c. Hair cells within the semicircular canals fire action potentials in response to a change in position. d. Movement of endolymph within the semicircular canals bends hair cell stereocilia by pushing on a gelatinous cupula covering the hair cells. e. All of the above

59. In the mammalian ovary, granulosa cells of the follicle are stimulated by follicle-stimulating hormone (FSH) to grow and mature. Granulosa cells are therefore similar to a. thecal cells of the follicle. b. Leydig cells in the testes of males. c. endometrial cells. d. Sertoli cells in the testes of males. e. cells of the corpus luteum.

59. Which of the following is most likely to inhibit the firing of an action potential in a postsynaptic cell? a. The binding of acetylcholine to acetylcholine receptor-mediated channels b. A reduction of acetylcholinesterase in the synaptic cleft of a neuromuscular junction c. The opening of voltage-gated Na+ channels and the entrance of Na+ into the cell d. The opening of chloride channels on the postsynaptic membrane and the entrance of Cl‒ into the cell e. A decrease in inhibitory inputs reaching the cell

6. The major form of stored energy in animal bodies is _______ because it _______. a. protein; is a long-term energy storage form b. glycogen; breaks down into readily usable carbohydrates c. glycogen; is lightweight d. fat; has the highest energy content per gram e. fat; is readily stored and dissolved in water

60. In the mammalian ovary, granulosa cells of the follicle produce inhibin, which makes them similar to a. thecal cells of the follicle. b. Leydig cells in the testes of males. c. endometrial cells. d. Sertoli cells in the testes of males. e. cells of the corpus luteum.

61. Some patients with breast cancer receive aromatase inhibitors as part of their medical treatment. Such an inhibitor causes a. enhanced growth and maturation of granulosa cells in the ovary. b. enhanced secretion of inhibin. c. low progesterone levels. d. low estrogen levels. e. Both a and c

61. The glycolytic system by which muscles obtain ATP a. relies on creatine phosphate. b. is also referred to as the immediate system. c. is the most efficient means of producing ATP. d. produces lactic acid as a by-product. e. completely metabolizes carbohydrates and fats.

62. Arthropods have evolved compound eyes consisting of large numbers of a. retinas. b. cones. c. eye cups. d. ommatidia. e. pupils.

62. Due to the activity of carbonic anhydrase, within the lung there is a concentration gradient of CO2 that is higher in the erythrocyte than in the _______, and a concentration gradient of _______ that is higher in the plasma than in the _______. a. plasma; HCO3-; plasma b. plasma; HCO3-; lung c. lung; CO2; lung d. lung; HCO3-; erythrocyte e. lung; HCO3-; lung

63. Injections of a synthetic form of _______ will induce labor in a pregnant woman. a. estrogen b. human chorionic gonadotropin c. progesterone d. oxytocin e. prolactin

63. Which of the following statements about MHC molecules is false? a. MHC proteins are cell membrane glycoproteins. b. The major role of MHC proteins is to present antigens to T cell receptors. c. Class I MHC proteins are found on the surface of every nucleated cell. d. Class II MHC molecules are found on the surface of T cells. e. MHC proteins are used by the immune system to identify cells as "self" versus "nonself."

64. A lipase is an enzyme that breaks down a. carbohydrates. b. nucleic acids. c. proteins. d. fat molecules. e. fatty acids.

64. A major disadvantage of the glycolytic system for supplying ATP to muscle fibers is a. the inefficiency of glycolysis compared to aerobic respiration. b. the long period of time that is required before it can start supplying ATP. c. that it leads to the accumulation of lactic acid. d. Both a and c e. All of the above

64. T cells are stimulated by the binding of antigen‒MHC complex to the T cells' receptors. The outcome of this interaction (i.e., whether it leads to formation of antibodies or to the death of the cell with the antigen‒MHC complex) depends on a. which class of MHC protein is involved. b. which type of T cell is involved. c. whether perforin is produced. d. All of the above e. None of the above

65. Which of the following statements about visual accommodation is false? a. Accommodation is the process by which objects from different portions of the visual field are focused on the retina. b. Vertebrates such as fish and reptiles accommodate by moving the lens relative to the retina. c. The suspensory ligaments keep the lens flattened. d. When a person attempts to focus on a distant object, the ciliary muscles contract. e. The ciliary muscles change the shape of the eye by counteracting the action of the suspensory ligaments.

66. Which of the following mature in the thymus? a. TC cells b. TH cells c. TREGS cells d. All of the above e. None of the above

67. When a person undergoes renal dialysis, a machine is used to replace the function of the kidneys. Substances to be removed from the blood move across the dialysis membrane into the dialysis solution. To be maximally effective at removing urea from the blood, the concentration of urea in the dialysis solution should be a. the same as it is in the blood. b. slightly lower than it is in the blood. c. slightly higher than it is in the blood. d. zero. e. much higher than it is in the blood.

67. Which of the following is not one of the mechanisms that facilitates the return of venous blood to the heart? a. Gravity, when veins are above the heart b. Contraction of skeletal muscles c. Breathing d. Contraction of smooth muscle in most veins of the body e. Valves in veins

68. Chylomicrons are like the tiny micelles of dietary fat in the lumen of the small intestine in that both a. are coated with bile. b. are lipid soluble. c. travel through the lymphatic system. d. contain triglycerides. e. are coated with lipoproteins.

68. The desensitization treatment for allergies involves injections of small amounts of the allergen: enough to trigger the production of _______, but not enough to trigger the production of _______. a. IgE; IgG b. histamines; IgM c. histamines; IgG d. IgG; IgE e. IgG; IgM

68. Which of the following best describes how an earthworm moves? a. It stretches its longitudinal muscles and pushes its fluid-filled body cavity forward. b. It forms pseudopods that ooze forward or backward. c. It uses the coordinated beating of many cilia. d. It alternates contractions of longitudinal and circular muscles. e. It contracts longitudinal muscles, which puts pressure on the hydrostatic skeleton and causes it to extend.

69. Which of the following statements about angiotensin is false? a. It constricts the efferent renal arteries. b. It stimulates thirst. c. It leads to release of aldosterone. d. It leads to decreased central blood pressure. e. It constricts peripheral blood vessels throughout the body.

7. In what way is a closed circulatory system more efficient than an open circulatory system? a. A closed circulatory system is a closed loop and therefore does not require a heart for pumping blood. b. An open circulatory system relies on diffusion to deliver nutrients to tissues. c. A closed circulatory system relies on hemoglobin rather than on cyanoglobin. d. In a closed circulatory system, blood vessels can control the delivery of O2 to specific tissues based on need. e. All of the above

7. The rate at which a gas diffuses between two locations is _______ the distance between those locations. a. unrelated to b. positively related to c. the square root of d. negatively related to e. None of the above

72. The retrovirus HIV specifically destroys T helper cells and thus disrupts the _______ response. a. humoral immune b. cellular immune c. inflammatory d. Both a and b e. Both a and c

73. PCO2 is monitored carefully by the human body, and any changes in it lead quickly to changes in respiratory rate. The actual stimulus that leads to increased respiratory gas exchange is a. PN2. b. PO2. c. temperature as measured at the hypothalamus. d. blood pH. e. pulse rate.

73. Which of the following would not be one of the body's responses to dehydration caused by foodborne illness? a. Release of ADH from the posterior pituitary b. Increased reabsorption of water c. Increased permeability of the collecting ducts d. Release of atrial natriuretic peptide (ANP) by the heart e. Decreased volume of urine produced

75. Cells that become infected by HIV include a. macrophages. b. TH cells. c. dendritic cells. d. All of the above e. None of the above

75. The dorsal horn of the spinal column contains the a. receptors for sensory input. b. stretch receptors involved in the knee-jerk reflex. c. cell bodies of motor neurons. d. axons of sensory neurons. e. white matter of the spinal column.

75. Which of the following mechanisms regulates blood pressure in the circulatory systems of mammals? a. Changes in the force of heart contraction b. Constriction and relaxation of arteriole wall sphincters c. Adjustments to the volume of blood contained in the veins d. All of the above e. None of the above

76. The role of cartilage in the human skeleton is to a. provide stiffness and resiliency to the surface of joints. b. add stiffness to structures such as the nose. c. provide a reservoir of calcium. d. Both a and b e. All of the above

76. Which of the following is not one of the activities carried out by the liver in the regulation of fuel metabolism? a. Conversion of nutrients into glycogen and fat b. Gluconeogenesis c. Synthesis of plasma proteins from amino acids d. Production of high-density lipoproteins (HDL) for deposit in adipose tissue e. Processing of chylomicrons from the small intestine

77. The "blind spot" is a region of the retina that is unable to detect light. Which of the following is the most likely explanation for the inability of the blind spot to detect light? a. It contains an unusually high number of rod cells. b. It contains an unusually high number of cone cells. c. It is the focal spot of incoming light. d. It is caused by a lack of photoreceptors where the optic nerve leaves the eye. e. It is caused by oversaturation of photoreceptors by light.

78. Low-density lipoproteins (LDLs) are about _______ percent protein, _______ percent lipids, and _______ percent cholesterol. a. 25; 50; 25 b. 30; 30; 40 c. 30; 40; 30 d. 25; 25; 50 e. 35; 30; 35

8. Receptor potentials produce action potentials in two ways: by generating action potentials within the sensory cells, or by causing the release of _______, which induces an associated neuron to generate action potentials. a. a hormone b. ATP c. interleukin d. a neurotransmitter e. glucagon

80. All of the following are opportunistic infections often associated with AIDS except for a. Kaposi's sarcoma. b. Pneumocystis pneumonia. c. Epstein-Barr virus. d. blood-clotting diseases such as hemophilia. e. lymphomas

85. Haversian systems consist of a. osteocytes completely isolated from other osteocytes by their matrix. b. osteoblasts that will give rise to osteoclasts. c. a meshwork of cancellous bone tissue. d. cylindrical units surrounding a canal of blood vessels. e. a honeycomb network of bone matrix.

86. People who have a strong allergic reaction to a bee sting or other allergen often carry an EpiPen, which delivers a single dose of epinephrine to prevent the reaction. The product carries a warning label from the manufacturer cautioning those users who also have high blood pressure. Why is this warning necessary? a. Epinephrine is part of the parasympathetic response and therefore will raise their blood pressure even higher. b. Epinephrine forms acetylcholine, which can cause a fatal rise in blood pressure. c. Epinephrine decays into vasopressin, which can cause a fatal drop in blood pressure. d. Epinephrine is part of the sympathetic response and therefore will raise their blood pressure even higher. e. Epinephrine stimulates the medulla to release large quantities of norepinephrine, which will raise their blood pressure even higher.

86. When you lift your knee to stand on one leg, the bent knee joint has acted as a(n) a. load arm. b. effort arm. c. extensor. d. fulcrum. e. flexor.

9. In most vertebrate neurons, an action potential arrives at the axon terminal and causes the release of chemical messenger molecules. These molecules are a. ATP. b. glucose. c. myelin. d. neurotransmitters. e. vesicles.

9. Which of the following is an advantage of closed circulatory systems as compared to open circulatory systems? a. Transport occurs more rapidly in closed systems. b. In closed systems, the diameter of the vessels can be changed to control the flow of blood. c. In closed systems, cells and large molecules can be kept separate from the animal's intercellular material. d. Both a and b e. All of the above

91. If an engineer designed a skeletal lever system for maximum force, a. the muscle would be inserted close to the joint and the load would also be close to the joint. b. the muscle would be inserted far from the joint and the load would also be far from the joint. c. the muscle would be inserted close to the joint and the load would be placed far from the joint. d. the muscle would be inserted far from the joint and the load would be placed close to the insertion point. e. a large muscle would be used.

1. Smallpox last occurred as a human pathogen a. in 432 bce. b. during the U.S. Civil War. c. during the French Revolution. d. in 1938. e. in 1978.

10. If an extremely heavy rainfall dilutes the salt ponds inhabited by the brine shrimp Artemia, how will the shrimp respond physiologically? a. They will transport salt out of their extracellular fluids to the environment. b. They will move water across their gill membranes by means of active transport. c. They will maintain osmolarity of their extracellular fluids below environmental levels. d. They will osmoconform with their surroundings. e. They will transport salt from the environment to their extracellular fluids.

10. When an action potential reaches an axon terminal, it can cause the release of neurotransmitters into the synaptic cleft. Which of the following is a possible sequence of events that could follow? a. Neurotransmitters diffuse from the presynaptic neuron and cause demyelination of the postsynaptic neuron. b. Neurotransmitters are actively transported by vesicles into the postsynaptic neuron, causing a local potential. c. Neurotransmitters are reabsorbed into the presynaptic neuron, exciting the presynaptic neuron. d. Neurotransmitters remain in the synaptic cleft, changing the resting membrane potential of the postsynaptic neuron. e. Neurotransmitters diffuse across the synaptic cleft, bind to receptors on the postsynaptic neuron, and inhibit activity in the postsynaptic neuron.

10. Which of the following statements is true? a. Asexual reproduction involves an inefficient use of resources. b. Sexually reproducing species are found almost exclusively in relatively constant environments where genetic diversity is relatively unimportant. c. Because it is produced by meiosis, a bud is genetically different from the parent. d. Only lost limbs can be replaced by regeneration. e. In some species, parthenogenesis requires all the sexual behaviors of courtship and mating.

11. Aquatic animals that lack an internal system for transporting O2 a. often have flat, leaflike bodies. b. are usually small. c. may have a very thin body built around a central cavity through which water circulates. d. have cells that are all close to the respiratory medium. e. All of the above

11. Parthenogenesis a. is theoretically possible but has never been confirmed in nature. b. occurs only in fish. c. is the development of offspring from unfertilized eggs. d. allows some species to produce only females. e. Both c and d

11. The magnitude of a receptor potential a. depends on the strength of the incoming action potential. b. remains high even after a long period of stimulation. c. is the same no matter what the type of stimulus. d. depends on the amount of neurotransmitter released. e. affects the frequency of resulting action potentials.

13. Ammonia, urea, and uric acid are waste products derived from the metabolic breakdown (catabolism) of a. carbohydrates. b. lipids. c. nucleic acids. d. proteins. e. Both c and d

13. The blood-brain barrier protects the brain a. mostly during fetal development. b. from exposure to toxic chemicals. c. by maintaining a blood supply for the brain that is separate from the rest of the body. d. through the action of astrocytes that reduce the permeability of small blood vessels. e. Both b and d

15. First haploid germ cells produced in spermatogenesis a. Sperm b. Spermatogonia c. Spermatids d. Primary spermatocytes e. Secondary spermatocytes

16. Many passengers on a cruise ship at sea are fighting flu-like symptoms. Which of the following is (are) among the first components of the immune system to be involved in their bodies' defense against the pathogen? a. Antibodies b. Lysozymes c. Mucus d. T lymphocytes e. Both b and c

16. Which of the following would be the most likely result of a disease that destroys astrocytes? a. Axons in the brain would no longer be insulated. b. The blood‒brain barrier could be weakened, allowing toxins to pass into the brain. c. Neurons in the brain would be deprived of nutrients. d. Peripheral nerves would show degradation of the myelin sheath. e. Both b and c

17. A challenge to modern medicine is to design drugs that target the brain. Existing knowledge about the ability of _______ to cross the blood‒brain barrier may be an important starting point in the design of new treatments. a. antibodies b. glucose c. astrocytes d. gases e. lipid-soluble substances

17. A paleontologist finds a fragment of a fossilized vertebrate that indicates that the animal had a four-chambered heart with two atria and two ventricles. The animal could have been a(n) a. fish. b. amphibian. c. crocodile. d. bird. e. Both c and d

17. MHC I proteins a. are found primarily on immune system cells. b. protect a developing fetus from its mother's immune system. c. are found on the surface of most mammalian cells. d. are important self-identifying labels. e. Both c and d

17. The anti-acne medication Retin-A, also used for reduction of wrinkles, has the active ingredient all-trans retinoic acid. If ingested, it can be toxic, but surprisingly it is chemically related to other forms of vitamin A you get in your diet from a. fruits. b. vegetables. c. liver. d. dairy products. e. All of the above

18. Bright light shining directly into one's eye will directly trigger a. an ionotropic sensory receptor. b. the opening of a cation channel. c. chemoreceptor binding. d. the opening of voltage-gated channels. e. a second messenger system.

18. While examining histological sections derived from the ovaries of human females at various life stages, you come across a slide from the prenatal period. Which of the following would you see on this slide? a. Oogonia b. Primary oocytes c. Secondary oocytes d. Ova e. Both a and b

2. Researchers recently reported that the green sea slug, Elysia chlorotica, can incorporate genes from algae, allowing them to use solar energy to meet their energy needs. Sea slugs can therefore be described as a. predators. b. heterotrophs. c. carnivores. d. herbivores. e. autotrophs.

2. Which of the following is not one of the functions performed by excretory systems? a. Regulating osmotic potential and the volume of extracellular fluids b. Eliminating substances that are present in excess c. Conserving substances that are valuable or in short supply d. Eliminating nitrogenous wastes e. Actively transporting water back into the extracellular fluid

20. Which of the following is least likely to help a patient who complains of night blindness? a. Fruits b. Vegetables c. Liver d. Dairy products e. Whole grains

20. Which of the following supports the hypothesis that you are undergoing an innate immune response after exposure to a pathogen? a. An increase in lysozyme production b. Inflammation at the site of exposure c. Increased flow of mucus d. Phagocytosis of the pathogen is observed e. All of the above

22. Crocodilians differ from other (nonavian) reptiles in that they have a. separate pulmonary circulation. b. lungs and no gills. c. an open circulatory system. d. more muscular atria. e. a four-chambered heart.

22. Which of the following is the most likely nutritional deficiency in a person showing anemia but who eats liver regularly? a. Pantothenic acid b. Biotin c. B12 (cobalamin) d. E (tocopherol) e. Folic acid

23. Of the various stages of human life, the earliest time that an arrested primary oocyte would resume meiosis would be a. during prenatal development. b. at birth. c. when it is fertilized. d. at menopause. e. at puberty.

25. In the human heart, blood is pumped from the left ventricle into the a. right ventricle. b. left atrium. c. right atrium. d. pulmonary circuit. e. systemic circuit.

25. Which of the following factors accounts for the efficiency of gas exchange in fish gills? a. Maximized surface area b. Minimized path length for diffusion c. Countercurrent flow of blood and water over opposite sides of the gas exchange surfaces d. Unidirectional flow of the environmental medium over the gas exchange membranes e. All of the above

25. Which of the following statements about the toll cell-signaling pathway is false? a. It was originally discovered in insects, but it has human counterparts. b. It involves activating NF-B, a transcription factor. c. It is stimulated by molecules made by pathogens. d. It is part of the innate and adaptive immune responses in mammals. e. Activation of the pathway inhibits gene transcription in macrophages, dendritic cells, and natural killer cells.

26. Because of the voltage difference across the membrane of a neuron and the different ion concentrations on either side of the membrane, ions would cross the membrane if they could. What is the importance, therefore, of a neuron maintaining a membrane potential? a. It maintains an electrical balance in the cell. b. Cellular activity requires more Na+ than K+. c. If the ions were in equilibrium, the cell would shrink by losing water through osmosis. d. It prevents the electrical and chemical gradients from reaching equilibrium, a process that would require a great deal of energy. e. It allows a cell to respond to a stimulus that changes its permeability to ions.

26. In humans, the _______ empties into the right atrium. a. pulmonary vein b. inferior vena cava c. superior vena cava d. pulmonary artery e. Both b and c

28. How is the information from a complex odorant molecule transmitted to the olfactory bulb? a. The frequency of action potentials in olfactory neurons is increased. b. The odorant molecule increases its binding to one type of receptor. c. The odorant molecule combines with other odorants to increase the perceived smell. d. The odorant molecule activates one glomerulus in the olfactory bulb. e. Different regions of one odorant molecule can bind to different receptor proteins.

29. In the following equation, which quantity represents the volume of your normal breath? Total lung capacity = residual volume + expiratory reserve volume + inspiratory reserve volume + tidal volume a. Total lung capacity b. Residual volume c. Expiratory reserve volume d. Inspiratory reserve volume e. Tidal volume

30. A filter feeder acquires food items by a. restraining prey with poison. b. restraining prey by means of claws and jaws. c. ingesting mud and extracting particles. d. filtering food substances from the blood. e. extracting particles suspended in water.

31. An electrochemical gradient across a membrane a. depends on the ion concentration gradient. b. depends on the voltage difference across the membrane. c. is a force acting on ions. d. determines the direction and amount of net movement of ions through ion channels. e. All of the above

31. Skeletal muscle fibers show a range of responses to different levels of stimulation because a. each muscle fiber contraction is "all or none." b. the availability of Ca2+ sets an upper limit to the strength of the contraction. c. a new contraction can occur only after the resting condition is reached. d. following stimulation, the fiber stays contracted. e. individual twitches in quick succession in the same fiber can undergo summation.

31. _______ ingest both plant and animal food and process their food through _______ digestion. a. Predators; intracellular b. Omnivores; intracellular c. Carnivores; intracellular d. Herbivores; extracellular e. Omnivores; extracellular

32. Anadromous bony fish, such as shad, leave the ocean and return to their natal freshwater streams to breed. Given this change in environment from salt water to freshwater, what changes would you expect to see in their osmoregulation? a. Increased drinking rate b. Decreased concentration of urine c. Change in the direction of ion-pumping across gills to draw more ions from the water, moving them into the blood d. Increased absorption of ions in their guts e. b, c, and d

32. The strength or weakness of a muscle contraction depends on a. the number of motor units activated. b. the frequency with which motor units fire. c. the number of muscle fibers stimulated. d. Both a and b e. All of the above

32. Which of the following represents the correct air pathway during inhalation in humans? a. Pharynx trachea bronchi larynx alveoli b. Larynx trachea pharynx bronchi alveoli c. Trachea larynx pharynx bronchi alveoli d. Trachea larynx pharynx alveoli bronchi e. Pharynx larynx trachea bronchi alveoli

33. A fundamental difference between saprobes and detritivores is that a. saprobes have long snouts that allow them access to food that is unavailable to detritivores. b. saprobes absorb nutrients from dead organisms. c. detritivores are primarily bacteria. d. detritivores seek out dead organic items and eat them. e. Both b and d

33. When an individual is first exposed to the smallpox virus, several days pass before significant numbers of specific antibody molecules and T cells are produced. However, a second exposure to the virus causes a large and rapid production of antibodies and T cells. This response is an example of a. antigenic determinants. b. phytoalexins. c. phagocytosis. d. interferon production. e. immunological memory.

34. Marine bony fishes acquire salt when they feed. They handle this salt load by a. producing very dilute urine. b. excreting it via the rectal gland. c. excreting ions from gills. d. not absorbing some ions from the gut. e. Both c and d

34. Research in recent years has described the existence of a diverse community of heterotrophs in the deepest parts of the ocean. These organisms ingest dead organic matter that falls down from the surface, and therefore can be described as a. predators. b. omnivores. c. carnivores. d. herbivores. e. detritivores.

36. Heart murmurs result from defective a. heart muscle. b. arterioles. c. ventricular contraction. d. blood supply to the heart. e. heart valves.

36. Mammals differ from other amniotes in that a. most species are viviparous. b. they have internal fertilization. c. most species have a placenta. d. they have paired ovaries. e. Both a and c

37. Considering the arrangement of blood vessels in the vertebrate kidney bringing blood to and from the glomerulus, a(n) _______ in the diameter of the _______ arteriole could result in an increased rate of filtration. a. increase; afferent b. decrease; afferent c. decrease; efferent d. increase; efferent e. Both a and c

37. Defective heart valves that do not close completely result in a. a turbulent blood flow within the heart. b. some blood flowing back into the atrium with each heartbeat. c. effects that are noticed upon contraction, or systole, of the muscle. d. what is called a heart murmur. e. All of the above

37. Which of the following is most likely to cause the opening of a voltage-gated channel in a cell membrane? a. Light causing a response in a photoreceptor b. A taste molecule binding to a taste receptor c. Mechanical pressure exerting a pull on a membrane d. Bathing a neuron in fluid with a high concentration of Na+ ions e. A rise in the membrane potential of a nerve cell

38. Testosterone can fuel prostate cancer. Which of the following approaches would not be included in treatments designed to lower testosterone in a patient with advanced prostate cancer? a. Blocking luteinizing hormone (LH) b. Removal of the testes c. Blocking gonadotropin-releasing hormone (GnRH) d. Blocking testosterone e. Cutting and tying off the vas deferens associated with each testis

38. Which of the following is not one of the adaptations that allows reptiles to live in terrestrial environments where water must be conserved? a. Scaly skin b. Excretion of uric acid c. Shelled eggs d. Reproduction involving internal fertilization e. Excretion of salts

39. Fast-twitch fibers a. are also called white muscle. b. fatigue rapidly. c. have fewer mitochondria per cell than do slow-twitch fibers. d. are also called glycolytic muscle. e. All of the above

39. Which of the following statements about the mechanics of ventilation in humans is false? a. If the pleural cavity is punctured, the lung may collapse. b. As the diaphragm relaxes, air is expelled from the respiratory system. c. As the diaphragm relaxes, pressure within the pleural cavities increases. d. Less energy is expended during the exhalation phase than during the inhalation phase. e. There is a slight positive pressure within the pleural cavities between breaths.

4. In general, _______ are cells of the nervous system that transduce physical or chemical stimuli into signals that are transmitted to other parts of the nervous system for processing and interpretation. a. receptor proteins b. effectors c. glial cells d. ion channels e. sensory cells

4. Which of the following is not a lymphoid tissue? a. Spleen b. Thymus c. Bone marrow d. Lymph nodes e. Red blood cells

40. Considering the arrangement of blood vessels in the vertebrate kidney bringing blood to and from the glomerulus, a(n) _______ in the diameter of the _______ arteriole could result in a decreased rate of filtration. a. decrease; afferent b. decrease; efferent c. increase; afferent d. increase; efferent e. Both a and d

40. Slow-twitch muscles a. are also called oxidative muscle. b. are also called red muscle. c. are well supplied with mitochondria. d. contain the oxygen-binding protein myoglobin. e. All of the above

40. Which of the following would not be an expected outcome of removal of the prostate gland? a. Decrease in volume of semen b. More acidic conditions in the male reproductive tract c. Failure of fibrinogen to convert semen into a gelatinous mass d. Greater difficulty for sperm to survive and move in the female reproductive tract e. Absence of secretions preceding climax

42. The cardiac cycle is controlled by a. Purkinje fibers. b. the sinoatrial node. c. the atrioventricular node. d. the bundle of His. e. All of the above

43. Which part of the blood is most efficient at carrying oxygen? a. Blood plasma solution b. Blood plasma proteins c. Blood platelets d. Membrane molecules of red blood cells e. Hemoglobin molecules of red blood cells

44. Following depolarization, the resting membrane potential in a neuron is restored when a. Na+ ions move into the cell through open Na+ channels. b. voltage-gated K+ channels move K+ ions into the cell. c. Cl- ion channels are closed. d. leak channels are inactivated. e. K+ ions are moved out of the cell through voltage-gated K+ channels.

44. The presence of _______ in a person's urine sample might suggest problems with glomerular filtration. a. water b. glucose c. ions d. amino acids e. plasma proteins

45. If the hypothalamus in a human male does not produce sufficient GnRH, a. the man makes functional sperm but is unable to ejaculate. b. the man's sperm lack functional flagella. c. the fluid needed to lubricate the man's urethra for sperm travel is defective. d. the man's semen lacks the fructose fuel needed for the sperm to swim. e. the man's Leydig cells do not make the testosterone needed to stimulate spermatogenesis.

49. In human males and females, a tumor on the anterior pituitary would most immediately affect secretion of _______ and _______. a. follicle-stimulating hormone; estrogen b. estrogen; progesterone c. follicle-stimulating hormone; progesterone d. luteinizing hormone; progesterone e. luteinizing hormone; follicle-stimulating hormone

5. Which of the following represents the order in which stored fuels are utilized in periods of starvation? a. Fats, glycogen, proteins b. Glycogen, proteins, fats c. Proteins, fats, glycogen d. Fats, proteins, glycogen e. Glycogen, fats, proteins

5. Which of the following statements regarding the stimulation of ionotropic receptor proteins within plasma membranes is true? a. Light alters the receptor proteins. b. The receptor proteins sense voltage changes and cause ion binding. c. Molecules binding to ionotropic receptor proteins open ion channels. d. Mechanical force can stimulate G proteins. e. The receptor proteins directly affect the opening of ion channels.

51. In the mammalian auditory system, which of the following structures transmit(s) signals between two flexible membranes? a. Hair cells in the semicircular canals b. Round window c. Oval window d. Cochlea e. Ear ossicles

51. Myoglobin benefits muscle cells by a. binding with O2 just as easily as hemoglobin does. b. contributing to the elasticity of flight muscle in birds. c. increasing the effectiveness of muscles used in short bursts. d. using hemoglobin as a reserve source of oxygen. e. releasing bound O2 at lower PO2 conditions than hemoglobin does.

52. Anaerobic exercise such as weight lifting a. increases strength. b. can do minor tissue damage. c. induces the formation of new actin and myosin filaments in existing muscle fibers. d. produces bigger muscle fibers and hence bigger muscles. e. All of the above

52. One V gene, one D gene, and one J gene encode for the _______ region of the _______ chain of a specific antibody. a. constant; light b. constant; heavy c. specific; light d. specific; heavy e. variable; heavy

53. Which of the following statements about the auditory functioning of the cochlea is false? a. The flexing of the round window follows the flexing of the oval window in a delayed fashion. b. The hair cells on the organ of Corti move against the rigid tectorial membrane. c. The intensity of the sound determines how many hair cells will be stimulated. d. The frequency of the sound determines which hair cells will be stimulated. e. Lower frequency sounds result in the stimulation of hair cells closer to the round window.

54. If the O2-binding curves were plotted for the following types of hemoglobin at the pH levels indicated, which curve would be to the right of all the others? a. Fetal human hemoglobin at pH 7.6 b. Adult human hemoglobin at pH 7.6 c. Adult human hemoglobin at pH 7.2 d. Fetal human hemoglobin at pH 7.2 e. Adult human hemoglobin at pH 7.2 in a person at a high altitude

54. Migrating birds often cross the Gulf of Mexico in a single flight thus their flight muscles demand extreme endurance. An examination of the muscles used to perform this activity would reveal a. substantial fuel reserves. b. low levels of ATPase activity. c. an abundance of blood vessels. d. many mitochondria. e. All of the above

55. Salmon returning to spawn in their native stream undertake a journey that requires extreme endurance. An examination of the muscles used to perform this activity would reveal a. substantial fuel reserves. b. low levels of ATPase activity. c. an abundance of blood vessels. d. many mitochondria. e. All of the above

56. Aerobic exercise such as jogging causes changes in skeletal leg muscles by increasing a. myoglobin. b. the number of mitochondria in the muscle cells. c. the enzymes involved in energy utilization. d. the density of capillaries. e. All of the above

56. The acetylcholine receptor is restored to its normal closed position by a. degradation of excess acetylcholine within the synapse. b. movement of Na+ ions into the muscle cell. c. movement of Na+ ions out of the muscle cell. d. exocytosis of acetylcholine. e. the activity of acetylcholinesterase.

56. Which of the following hormones would decline immediately following a bilateral oophorectomy (surgical removal of both ovaries)? a. Luteinizing hormone (LH) b. Gonadotropin-releasing hormone (GnRH) c. Follicle-stimulating hormone (FSH) d. Prolactin e. Estrogen

57. Which of the following is a benefit provided by fetal hemoglobin? a. It occurs in higher density in red blood cells than adult hemoglobin does. b. It releases O2 at a lower partial pressure than adult hemoglobin does. c. In the placenta, O2 diffuses from fetal hemoglobin to adult hemoglobin. d. At low O2 pressures, it is less likely to pick up oxygen than adult hemoglobin is. e. It transfers O2 from adult hemoglobin to the fetus.

59. Doctors trying to identify the nature of the immune response to a newly identified pathogen note that every time they isolate the antigen that the immune system is responding to, it is bound to the surface of a cell. This means that the component(s) of the immune system involved could be a. T cell receptors. b. antibodies. c. immunoglobulins. d. MHC proteins. e. All of the above

6. Mechanisms for the active transport of water a. are widespread among animals. b. rely on the sodium-potassium pump. c. allow for a higher rate of water transport than other transport methods provide. d. are responsible for reabsorption and secretion. e. do not exist; the movement of water occurs in response to differences in either pressure or solute concentration.

61. Which of the following experimental stimuli would most likely produce the greatest response in a postsynaptic neuronal membrane? a. A rapid stimulus that hyperpolarizes some parts of the membrane and depolarizes others b. A sudden stimulus that opens Ca2+ channels c. A single stimulus that increases neurotransmitter synthesis d. A steady stimulus that lowers the resting membrane potential e. A repeated stimulus that occurs at different sites on the postsynaptic cell

61. Which of the following statements is true? a. There is little polymorphism at MHC loci in humans. b. T cell receptors recognize antigenic fragments only when they are bound to an MHC molecule. c. T-helper cells have a surface protein that binds to antigen‒MHC class II complexes. d. Both a and b e. Both b and c

62. Histamine causes inflammation by a. making blood vessels expand and decreasing the permeability of capillaries. b. making blood vessels contract and decreasing the permeability of capillaries. c. making blood vessels contract and increasing the pressure in capillaries. d. decreasing the permeability of and increasing the pressure in capillaries. e. increasing the permeability of and the pressure in capillaries.

63. Electrical synapses a. do not perform temporal summation. b. contain gap junctions. c. can be excitatory. d. are a rapid means of signal transmission. e. All of the above

63. Which of the following statements about veins is true? a. Veins may hold as much as 60 percent of total blood volume at any one time. b. Veins are capacitance vessels. c. The walls of veins are more expandable than the walls of arteries. d. Veins are resistance vessels. e. a, b, and c

63. Which of the following statements regarding the human kidneys is false? a. As urine passes through collecting ducts, water leaves due to the concentration gradient established in the medulla. b. Sodium chloride diffuses out of the thin ascending limb of the loop of Henle. c. Sodium chloride is actively transported out of the thick ascending limb of the loop of Henle. d. Although the descending limb of the loop of Henle is permeable to water, the ascending limb is not. e. The urine passing through the collecting ducts is more concentrated than the surrounding interstitial fluid in the medulla, so water moves out of collecting ducts.

64. A scientist interested in studying active transport mechanisms could be advised to examine the process in the a. thin ascending limb of loop of Henle. b. collecting duct. c. descending limb of loop of Henle. d. distal convoluted tubule. e. proximal convoluted tubule and thick ascending limb of the loop of Henle.

64. Birth control pills containing synthetic estrogen and progesterone inhibit the ovarian cycle. A similar situation occurs during pregnancy, when high levels of estrogen and progesterone occur. During pregnancy, progesterone is produced first by the _______ and then by the _______. a. placenta; corpus luteum b. placenta; fetus c. corpus luteum; follicles remaining in the ovary d. anterior pituitary; hypothalamus e. corpus luteum; placenta

65. If the clearance of neurotransmitter from the synaptic cleft is prevented, which of the following will be the most likely result? a. The presynaptic cell will be unable to release more neurotransmitter. b. The postsynaptic cell will return to its resting potential. c. The postsynaptic cell will respond more quickly to a change in output of the presynaptic cell. d. The buildup of neurotransmitter will cause activation of the presynaptic cell. e. The postsynaptic cell will be constantly activated.

65. The enzyme lactase a. cleaves lactose into glucose and galactose. b. is produced by the small intestine. c. is absent in many humans after childhood. d. cleaves milk sugar. e. All of the above

65. Which of the following play(s) a role in the cellular immune response that is analogous to the role played by class II MHC proteins in the humoral immune response? a. Cytotoxic T cells b. T-helper cells c. CD28 d. Memory cells e. Class I MHC protein

66. Renal failure results in acidosis, which is a decrease in blood pH, because the kidneys normally a. secrete H+. b. reabsorb HCO3-. c. reabsorb H+. d. secrete HCO3-. e. Both a and b

66. What feature maximizes the absorption of light in the eyes of nocturnal animals? a. The black pigment behind the retina absorbs light. b. Nocturnal animals have a greater number of rods than diurnal animals do. c. Compared to diurnal animals, nocturnal animals produce more rhodopsin to absorb photons in dim light. d. The fovea is smaller than that of diurnal animals and therefore the retina contains fewer cones. e. The white reflective layer behind the retina reflects light.

67. Which of the following statements is false? a. MHC proteins often act as nonself antigens in tissue transplants between one individual and another. b. MHC proteins play an important role in self-tolerance. c. Developing T cells that fail to recognize the body's own MHC proteins undergo apoptosis in a normally functioning body. d. In transplants of tissues from one individual to a genetically identical individual, the material is usually recognized as self and is not rejected. e. Rejection of transplanted tissue can be avoided if the patient is treated with a drug that suppresses the humoral immune response.

69. In studies of dogs running on treadmills, C. R. Bainton found that when he doubled the speed of the treadmill, a. arterial CO2 levels increased exponentially by a power of 2. b. arterial CO2 levels were unchanged. c. respiratory rate was unchanged. d. respiratory rate increased. e. Both b and d

69. Ruminant animals, such as goats and cows, a. produce enzymes in their guts that break down cellulose. b. practice coprophagy. c. have a four-chambered stomach that provides a large surface area for nutrient absorption. d. produce hydrogen sulfide, an important greenhouse gas. e. get much of their protein from the digestion of microorganisms.

7. Smooth muscle differs from both cardiac and skeletal muscle in that a. it can act as a pacemaker for rhythmic contractions. b. its contractions are not due to interactions between neighboring microfilaments. c. its neighboring cells are electrically connected by gap junctions. d. its neighboring cells are tightly coupled by intercalated discs. e. its cell membranes are depolarized by stretching.

70. Lymph nodes are sites where a. lymph vessels join the venous system. b. nerve cell bodies innervating the lymphatic system are concentrated. c. the amount of fluid in the blood is regulated. d. new red blood cells are produced. e. microorganisms and foreign materials are removed by phagocytosis.

70. Which of the following is/are a benefit of an arthropod's tough exoskeleton and might help explain their tremendous evolutionary success? a. It protects against abrasion. b. It prevents water loss. c. It provides attachment sites for muscles. d. It bends at the animals' joints. e. All of the above

70. Which of the following statements about rods and cones is true? a. Cones are more sensitive at low light intensity. b. Rods are responsible for color vision. c. There are more cones than rods in the human retina. d. Strictly nocturnal animals have more cones than rods. e. In the fovea, the density of cones is greater than the density of rods.

71. Which of the following statements about the human retina is false? a. There are more rods than cones. b. There is a higher proportion of cones than rods in the fovea. c. Cones give us our highest visual acuity. d. Human peripheral vision involves more rod cells than cone cells. e. All of the above are true; none is false.

72. Which of the following birth control methods prevents ovulation? a. Tubal ligation b. Intrauterine device c. Mifepristone (RU-486) d. Rhythm method e. Birth control pill

74. The carotid and aortic bodies a. are blood vessels. b. respond to significant declines in PO2. c. increase respiration when blood volumes drop. d. are electrosensors. e. Both b and c

74. When you step on a sharp tack and pull your foot away, the movement involves all of the following except for a. the contraction of one set of leg muscles and the relaxation of an antagonistic set of muscles. b. a polysynaptic spinal reflex. c. interneurons between sensory and motor neurons in the spinal cord. d. sensory neurons that synapse directly with motor neurons in the spinal cord. e. motor input through the dorsal root that synapses with interneurons in the spinal cord.

76. If the normal activity of bipolar cells in the retina is blocked, a. rods and cones will be able to release neurotransmitter in response to dark. b. rods and cones will release more neurotransmitter in response to light. c. retinal ganglion cells will receive more input from the photoreceptor layer. d. amacrine and horizontal cells will synapse with ganglion cells. e. retinal ganglion cells will not fire action potentials.

77. Which of the following contributes to increased blood flow to tissues? a. Low O2 concentration b. Increased lactic acid concentration c. High CO2 concentration d. Both a and b e. All of the above

78. Even without treatment, some people infected with HIV may not develop severe symptoms of AIDS for a period of time. The longest period of time that has been recorded is _______ years. a. 2 b. 3-4 c. 7-8 d. 10 e. 20 or more

79. Olympic wrestlers grapple with each other for relatively short but intense periods, relying on powerful skeletal muscles in their arms and legs to pin their opponents. What changes might you expect to see in their circulatory systems immediately after the match? a. Activation of the parasympathetic system b. A carefully maintained, constant stroke volume c. A decrease in norepinephrine secretion d. An increase in blood flow to the gut e. Relaxation of precapillary sphincters serving capillaries in the arms and legs

8. If a planet were discovered where the barometric pressure was 2,000 mm Hg and the air was 15 percent O2, the partial pressure of its O2 at sea level would be a. 15 percent. b. 30 percent. c. 15 mm Hg. d. 133 mm Hg. e. 300 mm Hg.

8. Ovaries produce estrogen and progesterone. Removal of the ovaries in the parthenogenetic whiptail lizard Cnemidophorus uniparens would result in a. the absence of male sexual behavior. b. the absence of female sexual behavior. c. repeated ovulations. d. a switch to sexual reproduction. e. Both a and b

8. Which of the following statements about energy storage is true? a. Carbohydrates are stored in the liver and in muscle as glucose. b. Fat is not an important form of stored energy. c. Fat has the lowest energy content per gram. d. Protein is the most important energy storage component. e. The total glycogen stores are usually not more than a day's energy requirements.

80. A genetic carrier is defined as a person who carries a specific gene for a particular disease but does not have the disease. Suppose both members of a couple know they are carriers for a disease that could be fatal for any child they produced. They would like to have children but are worried about the risk. Which of the following procedures might a physician recommend? a. In vitro fertilization (IVF) b. Artificial insemination c. Intracytoplasmic sperm injection d. Preimplantation genetic diagnosis (PGD) e. Both a and d

80. An antelope sprints quickly away from a predator, relying on anaerobic respiration in the powerful skeletal muscles of its legs. What might you expect to see in its circulatory system immediately after escaping the predator? a. Activation of the parasympathetic system b. A carefully maintained, constant stroke volume c. A decrease in norepinephrine secretion d. An increase in blood flow to the gut e. Relaxation of precapillary sphincters serving capillaries in the legs

81. The migration of ruby-throated hummingbirds from the eastern United States to Central America requires a long flight over the Gulf of Mexico. What changes might you expect to see in their circulatory systems immediately after the flight? a. Activation of the parasympathetic system b. A carefully maintained, constant stroke volume c. A decrease in norepinephrine secretion d. An increase in blood flow to the gut e. Relaxation of precapillary sphincters serving capillaries in the wings

81. Which of the following statements about bone is false? a. Astronauts who spend long periods of time in zero gravity experience decalcification of their bones. b. Osteoclasts are derived from the lineage of cells that produce white blood cells. c. Most bones have compact and cancellous regions. d. Bones may become thicker or thinner depending on the amount of stress placed on them. e. Osteoclasts lay down bone in layers, creating compact bone.

82. Which of the following statements about the long bones in a human skeleton is false? a. Ossification starts at the center of developing long bones. b. Elongation occurs at epiphyseal plates. c. Secondary sites of ossification occur at the ends of developing long bones. d. They are first laid down as cartilage. e. They form on a scaffold of connective tissue membrane.

83. Which of the following hormones causes constriction of the blood vessels? a. Epinephrine b. Angiotensin c. Antidiuretic hormone (vasopressin) d. Both a and b e. All of the above

9. A scientist wishing to study a species that conserves body water would not choose a species from which of the following groups? a. Birds b. Mammals c. Lizards and snakes d. Marine bony fishes e. Freshwater bony fishes

9. Oxygen can be exchanged more easily in air than in water because a. the oxygen content of air is higher than that of water. b. oxygen diffuses more slowly in water than in air. c. water is more dense than air, so more energy is required to move it. d. Both a and b e. All of the above

9. Which muscle type uses calcium to trigger actin-myosin interactions for movement? a. Smooth b. Cardiac c. Skeletal d. Both a and b e. All of the above

9. Which of the following statements about lymph is false? a. It is filtered in the lymph nodes. b. White blood cells inspect it in lymph nodes for pathogens and other nonself elements. c. It is derived in part from blood. d. It contains soluble proteins. e. It travels primarily in arterioles and venuoles.

94. The role of tendons is to join a. two bones. b. two ligaments. c. bone and ligament. d. muscle and ligament. e. muscle and bone.

Bio 105 Final (Master)

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