IMMUNOLOGY
57. All of the following are necessary for a humoral response except
a. TC cells.
b. TH cells.
c. B cells.
d. cytokines.
e. antigenic determinant.
Answer: a
58. Which of the following is not a characteristic of an inflammatory reaction?
a. Release of histamine
b. Invasion of the region by phagocytes
c. Binding of IgG
d. Dilation of capillaries
e. Escape of blood plasma
Answer: c
59. To make a hybridoma, a plasma cell is fused to a _______ cell.
a. carcinoma
b. B
c. macrophage
d. tumor
e. liver
Answer: d
60. An important organ that helps to protect against autoimmune disease is the
a. kidney.
b. spleen.
c. thymus.
d. adrenal gland.
e. tonsils.
Answer: c
61. The core of HIV contains
a. a protease.
b. reverse transcriptase.
c. integrase.
d. two identical RNA molecules.
e. All of the above
Answer: e
62. Viral membrane proteins of HIV are synthesized
a. in the core particle.
b. in the infected cell’s nucleus.
c. on the surface of the ER.
d. in the cytoplasm.
e. in the Golgi apparatus.
Answer: c
63. Cells that get infected by HIV generally have
a. CD4 membrane proteins.
b. gp120.
c. gp41.
d. antigen-bound T cell receptors.
e. All of the above
Answer: a
64. HAART is
a. a hypersensitive AIDS patient.
b. highly active antiretroviral therapy.
c. HIV and AIDS advanced retroviral treatment.
d. highly advanced AIDS RNA treatment.
e. hereditary AIDS acquired and retransmitted.
Answer: b
65. An immune response that is characterized by a short lag time and high production of
antibodies is the _______ response.
a. primary immune
b. secondary immune
c. attenuation
d. effector cell
e. polyclonal
Answer: b
66. A medical “smart bomb” consists of the practical application of monoclonal antibodies, also
known as
a. immunoassays.
b. passive immunization.
c. immunotherapy.
d. DNA vaccination.
e. attenuation.
Answer: c
67. The primary immune response is characterized by
a. short lag time.
b. a high rate of antibody production.
c. a large production of T cells.
d. a large production of antibodies.
e. the addition of memory cells to the immune system.
Answer: e
68. Antigen-presenting cells include
a. macrophages.
b. dendritic cells.
c. B cells.
d. Both a and b
e. a, b and c
Answer: e
69. T cells
a. have immunoglobulin receptors.
b. have antibodies as effector molecules.
c. develop from activated B cells.
d. are secreted by plasma cells.
e. release perforin.
Answer: e
70. Binding of a molecule from a pathogen to a receptor initiates a signal transduction pathway.
Which is the correct order of events in this pathway?
a. Phosphorylation of NF-B, binding of NF-κB to the promoter, activation of toll receptor,
transcription of defense genes
b. Binding of NF-κB to the promoter, phosphorylation of NF-κB, activation of toll receptor,
transcription of defense genes
c. Activation of toll receptor, phosphorylation of NF-κB, binding of NF-κB to the promoter,
transcription of defense genes
d. Activation of toll receptor, Binding of NF-κB to the promoter, phosphorylation of NF-κB,
transcription of defense genes
e. Binding of NF-κB to the promoter, activation of toll receptor, transcription of defense genes,
phosphorylation of NF-κB
Answer: c
71. All of the following are disorders of the immune system except
a. AIDS.
b. multiple sclerosis.
c. insulin-dependent diabetes mellitus.
d. HMC transplant rejection.
e. rheumatoid arthritis.
Answer: d
72. The five classes of antibodies differ from each other in terms of
a. the composition of their light and heavy chains.
b. their function.
c. the number of antigen binding sites.
d. whether they are immunoglobulins or proteins.
e. the site of B cell differentiation.
Answer: b
73. A person suffering from AIDS would likely have which one of the following diseases?
a. Rheumatoid arthritis
b. Lupus erythematosis
c. Multiple sclerosis
d. Kaposi’s sarcoma
e. Insulin-dependent diabetes mellitus
Answer: d
STUDY GUIDE QUESTIONS
Knowledge and Synthesis Questions
1. Phagocytes
a. are T and B cells.
b. present antigen on MHC II complexes.
c. digest nonself materials.
d. Both b and c
2. B cells
a. secrete antibodies.
b. present antigen on MHC II.
c. ingest antigens.
d. All of the above
3. Nonspecific responses in the immune system include
a. macrophages.
b. natural killer cells.
c. complement proteins.
d. All of the above
4. When the receptor of a TH cell binds to a pathogen being presented on a macrophage, it
a. activates itself.
b. secretes cytokines.
c. activates B cells.
d. All of the above
5. Part of the normal immune response includes
a. the production of B memory cells.
b. the production of memory macrophages.
c. antibody secretion by eosinophils.
d. the production of B cells that attack the individual’s own cells.
6. Antibody molecules are
a. produced by B cells and have a variable and a constant region.
b. secreted by B cells, once a signal (a cytokine) is received from a T cell.
c. produced by T cells and have a variable and a constant region.
d. Both a and b
7. Cytotoxic T cells
a. release cytokines that activate B cells.
b. attack pathogens by binding to cell surface antigens on those pathogens.
c. destroy pathogens by lysing them.
d. destroy host cells that are infected with virus.
8. The humoral response
a. is due to the secretion of antibodies.
b. occurs when T cells bind antigen-presenting cells.
c. is due to T cells secreting their receptors.
d. occurs when natural killer cells engulf cancer cells.
9. Autoimmunity is
a. active when organ transplantation is successful.
b. caused by clonal anergy.
c. the response of the immune cells attacking the body’s own tissues.
d. Both b and c
10. Patients with HIV are susceptible to a variety of infections because
a. the virus produces cell surface receptors that bind to pathogens, making it easier for those
pathogens to be infective.
b. synthesizing a DNA copy of the viral genome makes a person feel sick.
c. HIV attacks and destroys the T helper cells, which are central to mounting an effective
immune response, making those individuals more susceptible to other infections.
d. HIV destroys B cells so that antibodies cannot be made in response to invading pathogens.
11. DNA rearrangements in the B cell
a. are responsible for generating single B cells that can express many different antibodies.
b. lead to mutations in T cells resulting in the elimination of essential T cell genes.
c. occur only in B memory cells.
d. are responsible for generating many different antibodies, with each B cell expressing only one
set of identical antibodies.
12. Major histocompatibility proteins function in the immune system by
a. presenting antigen to T cells.
b. presenting self antigens to T helper cells so those T cells will continue to tolerate self
throughout the lifetime of the individual.
c. generating antibodies to different pathogens.
d. Both a and b
Answers
Knowledge and Synthesis Answers
1. d. Phagocytes are nonspecific cells (not B and T cells) that digest nonself materials and
present protein fragments of those nonself materials on their surface. They do not have
antibodies.
2. d. B cells are antigen-presenting cells; they bind antigen, digest it, present fragments of that
antigen on their MHC II proteins, and secrete antibodies.
3. d. Macrophages, natural killer cells, and complement proteins are all part of the nonspecific
response of the immune system. B and T cells are part of the specific response of the immune
system.
4. d. When the TH cell binds antigen being presented on a macrophage, it secretes cytokines,
which activate the TH cell and B cells.
5. a. In a normal immune response, B memory cells are made so that the organism can mount a
faster and more effective response to the pathogen if the organism ever encounters it again.
Memory macrophages do not exist. Eosinophils do not secrete antibodies. In an abnormal
immune response, B cells that attack the individual’s own cells can be activated, as seen in
autoimmune diseases.
6. d. T cells have cell surface receptors with a variable and a constant region and do not produce
antibody molecules. Antibodies are not produced by macrophages. Only B cells produce
antibodies in response to cytokines released from the TH cell. Each antibody molecule has two
identical heavy chains and two identical light chains, and each of those chains has a variable and
a constant region.
7. d. Cytotoxic cells bind to virus antigen being presented on MHC I protein and destroy those
cells. TH cells release cytokines to activate B cells. The antibodies of B cells bind cell surface
antigens on pathogens. Pathogens are lysed by complement proteins (and not by cytotoxic T
cells), which are activated by antibodies bound to those pathogens.
8. a. The humoral response refers to that part of the specific response that releases antibodies (B
cells) in the lymph and blood (the “humors” of the body). The cellular response is T cell
receptors binding antigen on antigen- presenting cells. T cells do not secrete their receptors.
9. c. Autoimmunity occurs when the immune cells attack the body’s own cells. Transplants can
be rejected if the transplanted tissue is recognized by the body as nonself, and is not a result of
immune cells attacking the body’s own tissue. Clonal anergy suppresses the immune response to
self antigens and thus works to prevent autoimmunity.
10. c. An HIV-infected individual is more susceptible to a variety of infections because the virus
destroys TH cells, which are essential for mounting an effective immune response. HIV does not
bind to pathogens; it binds to TH cells. HIV does not destroy B cells.
11. d. DNA rearrangements occur in B cells and result in each B cell expressing a unique kind of
antibody. DNA rearrangements also occur in T cells to generate T cell receptors. This
rearrangement does not destroy essential T cell genes. Memory B cells are cells in which the
DNA rearrangement has already occurred.
12. d. MHC proteins present nonself antigens and self antigens to T cells. T cells that react with
self antigens are destroyed, preventing autoimmunity. The cytokines of T cells (and not MHC
proteins) activate B cells. MHC proteins do not generate antibodies.
TEXTBOOK SELF QUIZ QUESTIONS
1. Phagocytes kill harmful bacteria by
a. endocytosis.
b. producing antibodies.
c. complement.
d. T cell stimulation.
e. inflammation.
2. Which statement about immunoglobulins is true?
a. They help antibodies do their job.
b. They recognize and bind antigenic determinants.
c. They encode some of the most important genes in an animal.
d. They are the chief participants in nonspecific defense mechanisms.
e. They are a specialized class of white blood cells.
3. Which statement about an antigenic determinant is not true?
a. It is a specific chemical grouping.
b. It may be part of many different molecules.
c. It is the part of an antigen to which an antibody binds.
d. It may be part of a cell.
e. A single protein has only one on its surface.
4. T cell receptors
a. are the primary receptors for the humoral immune system.
b. are carbohydrates.
c. cannot function unless the animal has previously encountered the antigen.
d. are produced by plasma cells.
e. are important in combating viral infections.
5. According to the clonal selection theory,
a. an antibody changes its shape according to the antigen it meets.
b. an individual animal contains only one type of B cell.
c. the animal 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.
6. Immunological tolerance
a. depends on exposure to antigen.
b. develops late in life and is usually life-threatening.
c. disappears at birth.
d. results from the activities of the complement system.
e. results from DNA splicing.
7. 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 gene segments.
e. their remarkable nonspecificity.
8. Which of the following play(s) no role in the antibody response?
a. Helper T cells
b. Interleukins
c. Macrophages
d. Reverse transcriptase
e. Products of class II MHC gene loci
9. The major histocompatibility complex
a. codes for specific proteins found on the surface of cells.
b. plays no role in T cell immunity.
c. plays no role in antibody responses.
d. plays no role in skin graft rejection.
e. is encoded by a single locus with multiple alleles.
10. Which of the following plays no role in HIV reproduction?
a. Integrase
b. Reverse transcriptase
c. gp120
d. Interleukin-1
e. Protease
Answers
1. a
2. b
3. a
4. e
5. c
6. a
7. d
8. d
9. a
10. d
ONLINE QUIZ QUESTIONS
1.Which of the following is not a feature of the immune response?
a.The ability to mount an initial non-specific defense
b.Specificity
c.The ability to respond to an enormous diversity of antigens
d.The ability to distinguish self from nonself
e.Memory
Answer: a
2.Which of these is not a nonspecific defense?
a.Physical barriers
b.Competing resident microorganisms
c.Secretions
d.Humeral response
e.Inflammation response
Answer: d
3.What accounts for the rapidity, specificity, and diversity of the immune response as well as
immunological memory and tolerance to self?
a.Class switching
b.Cellular immune response
c.Clonal selection
d.The immune response
e.The inflammation response
Answer: c
4.T cell receptors recognize and bind
a.Tc cells.
b.B cells.
c.processed antigens.
d.TH cells.
e.IgM antibodies.
Answer: c
5.Which of these is not a class of immunoglobulins?
a.IgM
b.IgB
c.IgA
d.IgE
e.IgD
Answer: b
6.Genetic diversity in _______ is/are primarily responsible for rejection of organ transplants.
a.MHC
b.developing T-cells
c.monoclonal antibodies
d.immunoglobulins
e.white blood cells
Answer: a
7.Which of the following is not a characteristic of immunoglobulins such as IgG?
a.A protein with a quaternary structure
b.Subunits held together by hydrogen bonding
c.Two heavy chains and two light chains
d.Variable and constant regions in each chain
e.Two antigen binding sites
Answer: b
8.Which of the following play(s) no role in the antibody response?
a.Helper T cells
b.Interleukins
c.Macrophages
d.Reverse transcriptase
e.Products of class II MHC gene loci
Answer: d
9.Diseases resulting from a failure in the immune recognition of self are called
a.HIVs.
b.cancers.
c.recognition failure disorders.
d.immune deficiency disorders.
e.autoimmune diseases.
Answer: e
10.Currently, the most effective drugs to treat HIV are those directed against the two enzymes,
a.DNA polymerase and protein kinase.
b.reverse transcriptase and protease.
c.pyruvate dehydrogenase and cyclic AMP.
d.DNA isomerase and RNA ligase.
e.DNA ligase and ribozyme.
Answer: b
11.T cells
a. secrete cytokines.
b. can be T helper cells.
c. eliminate altered self-cells.
d. a and b.
e. a, b, and c
Answer: e
12.Match the following cells and their functions correctly:
a. T-cell - secretes plasma cells
B-cell- precursor to antibodies
monocyte- example is a CD4 cell
macrophage- phagocytizes debris
b. T-cell - antigen presenting cell
B-cell- secretes hydrolytic enzymes
monocyte- precursor to macrophages
macrophage- produce memory B cells
c. T-cell - phagocytize B cells
B-cell- produces memory B-cells
monocyte- activates cytotoxic proteins
macrophage- an example is a CD4 cell
d. T-cell - an example is a T helper cell which secretes cytokines
B-cell- secretes plasma cells which produce memory B cells
monocyte- precursor to macrophages
macrophage- phagocitizes debris
e. T-cell - activates cytotoxic proteins
B-cell- phagocytizes B cells
monocyte- secretes plasma cells which produce memory B cells
macrophage- secretes plasma cells which produce memory B cells
Answer: d
13.Which cells are the first response to inflammation?
a. Neutrophil
b. Basophil
c. T cell
d. Macrophage
e. Eosinophil
Answer: a
14.Pregnancy tests are based on the ability of antigens to bind to specific molecules in saliva.
a. true
b. false
Answer: b
15.A pregnant woman would show which of the following results from a pregnancy test?
a. High levels of HCG and one colored band on the test strip
b. Lack of HCG and one colored band on the test strip
c. High levels of HCG and two colored bands on the test strip
d. Lack of HCG and two colored bands on the test strip
e. None of the above
Answer: c
16.The control zone is an important region that helps distinguish whether the strips are working
correctly .
a. true
b. false
Answer: a
17.All of the following except _______ are part of immunoglobulins.
a. epitopes
b. light chains
c. heavy chains
d. antigen-binding sites
e. C and V regions
Answer: e
18.Antigenic determinants specifically bind to
a. epitopes.
b. antigen-binding sites.
c. C-regions of the heavy and light chains.
d. complement.
e. B-lymphocytes.
Answer: b
19.The key concept of the clonal selection model is that
a. each of us can form many different kinds of antibodies.
b. particular antigens react with one of the five types of immunoglobulins.
c. each lymphocyte produces only one kind of antibody.
d. B-lymphocytes undergo mitosis to form a clone of plasma cells.
e. specific epitopes initiate mitotic division of one small subset of lymphocytes.
Answer: e
20.Class I MHC proteins work in the humoral immune response, while class II MHC proteins
function in cellular immune response.
a. True
b. False
Answer: b
21.T cells mature in the
a. thymus.
b. spleen.
c. bone marrow.
d. kidneys.
e. liver.
Answer: a
22.Perforin is released by
a. helper T cells.
b. cytotoxic T cells.
c. B cells.
d. plasma cells.
e. B memory cells.
Answer: b
23.Foreign antigens synthesized within body cells are presented by
a. class I MHC molecules to cytotoxic T cells.
b. class II MHC molecules to helper T cells.
c. class I MHC molecules to helper T cells.
d. class II MHC molecules to CD4-bearing cells.
e. class II MHC molecules to cytotoxic T cells.
Answer: a
24.Which of the following is not true about helper T cells?
a. They function in the humoral immune response.
b. They recognize polysaccharide fragments presented by class II MHC molecules.
c. They bear surface CD4 molecules.
d. They are subject to infection by HIV.
e. When activated, they secrete IL-2 and other cytokines.
Answer: b
25.An antigenic determinant associates with what part of an antibody?
a. The antibody-binding site
b. The heavy chain constant regions only
c. The variable regions of a heavy chain and light chain combined
d. The light chain constant regions only
e. The antibody tail
Answer: c
THERMO-REG /
HOMEOSTASIS
TEST FILE QUESTIONS
Fill in the Blank
1. The four types of tissues are epithelial, muscle, nervous, and _______.
Answer: connective
2. In certain “hot” fish such as bluefin tuna, heat is exchanged between vessels carrying blood in
opposite directions. This adaptation is called _______.
Answer: countercurrent heat exchange
3. The metabolic rate of a resting animal at a temperature within the thermoneutral zone is called
the _______.
Answer: basal metabolic rate
4. Small endotherms can extend the period over which they can survive without food by
dropping body temperature. This adaptive hypothermia is called _______.
Answer: daily torpor
5. The maintenance of more or less constant physiological conditions within an organism is
called _______.
Answer: homeostasis
6. _______ feedback amplifies a response.
Answer: Positive
7. Animals whose temperature fluctuates to match that of the environment are termed _______.
Answer: poikilotherms
8. Animals that can affect their body temperature by generating metabolic heat are called
_______.
Answer: endotherms
9. In vertebrates, the thermostat is located in the _______.
Answer: hypothalamus
10. During the condition called _______, when an endotherm’s body temperature is far below
normal, metabolic rates become _______. Although this condition can be harmful to endotherms,
it is a useful strategy for some overwintering mammals called _______.
Answer: hypothermia; lower; hibernators
11. In mammals, most nonshivering heat production occurs in the adipose tissue called _______.
Answer: brown fat
12. The linings of many hollow organs consist of _______ tissue.
Answer: epithelial
13. The most abundant protein in our bodies is _______, found in connective tissue.
Answer: collagen
14. Cells with the same characteristics form _______, and different tissues form discrete
structures with specific functions called _______.
Answer: tissues; organs
15. _______, derived from bacteria or viruses that invade the body, cause fever.
Answer: Pyrogens
4. Which term refers to organisms that depend largely on external sources of heat to maintain
body temperature?
a. Homeothermic
b. Endothermic
c. Heterothermic
d. Ectothermic
e. None of the above
Answer: d
5. In response to a 10°C rise in environmental temperature, an endotherm’s body temperature
will
a. rise at a constant rate.
b. fall at a constant rate.
c. fall to a point, then become stable.
d. rise to a point, then become stable.
e. remain relatively constant.
Answer: e
6. Which of the following adaptations would not favor an increase in an ectotherm’s body
temperature?
a. Muscle contractions
b. Cluster or huddling behavior
c. Decreased surface-to-surface contact with the cold environment
d. Circulatory changes to maintain core or internal temperatures greater than the animal’s
peripheral temperatures
e. Metabolic compensation
Answer: e
7. Readjustment of an organism’s metabolic rate to compensate for seasonal thermal change is
termed
a. homeostasis.
b. negative feedback.
c. metabolic compensation.
d. acclimatization.
e. regulation.
Answer: c
8. Which term best describes an organism that maintains a constant body temperature?
a. Ectotherm
b. Homeotherm
c. Heterotherm
d. Poikilotherm
e. None of the above
Answer: b
9. After cool nighttime temperatures have changed, a desert lizard crawls slowly from its burrow
and positions itself on a rock warmed by the mid-morning sun. Which one of the following is
most likely not one of the lizard’s thermoregulatory responses?
a. Orientation to the sun to maximize exposure to solar radiation
b. Increased peripheral circulation via dilation of surface blood vessels
c. Increased metabolic heat production
d. Increased physical contact between the warm rock and the relatively cool lizard
e. Orientation of the lizard on the rock into more suitable microenvironments to avoid cold air
currents
Answer: c
4. Which term refers to organisms that depend largely on external sources of heat to maintain
body temperature?
a. Homeothermic
b. Endothermic
c. Heterothermic
d. Ectothermic
e. None of the above
Answer: d
5. In response to a 10°C rise in environmental temperature, an endotherm’s body temperature
will
a. rise at a constant rate.
b. fall at a constant rate.
c. fall to a point, then become stable.
d. rise to a point, then become stable.
e. remain relatively constant.
Answer: e
6. Which of the following adaptations would not favor an increase in an ectotherm’s body
temperature?
a. Muscle contractions
b. Cluster or huddling behavior
c. Decreased surface-to-surface contact with the cold environment
d. Circulatory changes to maintain core or internal temperatures greater than the animal’s
peripheral temperatures
e. Metabolic compensation
Answer: e
7. Readjustment of an organism’s metabolic rate to compensate for seasonal thermal change is
termed
a. homeostasis.
b. negative feedback.
c. metabolic compensation.
d. acclimatization.
e. regulation.
Answer: c
8. Which term best describes an organism that maintains a constant body temperature?
a. Ectotherm
b. Homeotherm
c. Heterotherm
d. Poikilotherm
e. None of the above
Answer: b
9. After cool nighttime temperatures have changed, a desert lizard crawls slowly from its burrow
and positions itself on a rock warmed by the mid-morning sun. Which one of the following is
most likely not one of the lizard’s thermoregulatory responses?
a. Orientation to the sun to maximize exposure to solar radiation
b. Increased peripheral circulation via dilation of surface blood vessels
c. Increased metabolic heat production
d. Increased physical contact between the warm rock and the relatively cool lizard
e. Orientation of the lizard on the rock into more suitable microenvironments to avoid cold air
currents
Answer: c
28. _______ is the process of physiological and biochemical change that an animal undergoes in
response to seasonal changes in climate.
a. Acclimatization
b. Homeostasis
c. Sublimity
d. Metabolic compensation
e. Hybridization
Answer: a
29. Adaptations used by endotherms to reduce heat loss include which of the following?
a. Rounder body shapes
b. Shorter appendages
c. Increased thermal insulation
d. Both b and c
e. a, b, and c
Answer: e
42. If an animal exhibits metabolic compensation,
a. it adapts its physiology to local environmental conditions.
b. its metabolic rate is always slightly higher in summer.
c. its Q10 stays constant despite seasonal temperature change.
d. its body temperature and its metabolic rate are independent.
e. it uses the same reaction pathways at all temperatures.
Answer: a
43. Poikilothermic animals are those whose body temperature
a. is maintained at a constant level some of the time.
b. is maintained at a constant level all of the time.
c. fluctuates with environmental temperature.
d. is kept at a higher temperature than that of the environment.
e. is kept at a lower temperature than that of the environment.
Answer: c
44. Which of the following animals are endotherms?
a. Fishes
b. Amphibians
c. Birds
d. Mammals
e. Both c and d
Answer: e
45. Which of the following animals would be most successful with the part-time temperature
regulation strategy of heterothermy?
a. A desert lizard that basks in the sun
b. A deep ocean fish in an environment with little temperature change
c. An insect that is warm-blooded in flight and cold-blooded at rest
d. An amphibian that is sometimes in water and sometimes on land
e. A hummingbird that drops its body temperature at night
Answer: e
46. Which of the following animals is behaving as an endotherm in order to warm its body?
a. A moth that shivers its wings before flight
b. A black beetle that absorbs solar radiation
c. A snake that lies on a warm blacktop road
d. A fish that moves to a warm, shallow part of a pond
e. An insect that positions its body for maximum exposure to sunlight
Answer: a
47. A certain desert lizard thermoregulates as an ectotherm. Which of the following phenomena
would not be a part of its thermoregulatory behavior?
a. Staying in a burrow when the surface temperature is below 10°C
b. Basking in the sun during the early morning hours
c. Moving into the shade during the midday hours
d. Pressing its body to the ground during the midday hours
e. Consuming prey that is ectothermic
Answer: d
48. In which case would a poikilothermic animal have a higher body temperature than a
homeotherm would have?
a. When resting in an underground burrow
b. At midday on the desert floor
c. When swimming in the cold ocean
d. When basking in the early morning sun
e. When the poikilotherm is much larger
Answer: b
49. Which of the following exemplifies adaptive thermoregulatory behavior in humans?
a. A cowboy wearing a broad-brimmed hat
b. An Eskimo wearing lightweight white clothing
c. A desert home with large windows facing the sun
d. Swimming in winter weather
e. None of the above
Answer: a
50. Which physiological control mechanism is a response to a rise in body temperature?
a. Slower heart rate
b. Increased blood flow to the skin
c. Constriction of blood vessels in the skin
d. Contraction of muscles
e. Retention of water
Answer: b
51. What is the adaptive advantage of honeybee workers’ clustering to maintain warm
temperatures in the hive?
a. Protection of the queen bee
b. Protection of the comb structure
c. Optimal pollen collection
d. Optimal digestion of honey
e. Optimal brood development
Answer: e
52. Within a range of environmental temperatures called the thermoneutral zone, the metabolic
rate of an endotherm is
a. constant.
b. low and independent of temperature.
c. high and independent of temperature.
d. near the basal metabolic rate.
e. dependent upon the temperature.
Answer: b
53. In a mammal, metabolic rate is highest when the temperature is _______ the thermoneutral
zone and the animal is _______.
a. within; at rest
b. below; active
c. within; active
d. above; at rest
e. below; at rest
Answer: b
54. Which of the following statements about brown fat is false?
a. It contains abundant mitochondria.
b. It provides the most energy for shivering.
c. It allows metabolic fuels to be consumed without producing ATP.
d. It uses thermogenin to uncouple proton movement from ATP production.
e. It is more abundant in hibernating animals.
Answer: b
55. The mechanism of heat production in brown fat depends on
a. inefficient use of ATP in metabolism.
b. rapid breakdown of protein.
c. rapid breakdown of fatty acids.
d. the shivering of skeletal muscles.
e. uncoupling proton movement from ATP production.
Answer: e
56. Which of the following is an important adaptation of animals to cold climates?
a. Increased tendency to shiver
b. Thinner layers of body fat
c. Reduced density of fur or feathers
d. Reduced surface area-to-volume ratio
e. Increased flow of blood to surface
Answer: d
57. The elephant is better adapted to tropical habitats than to cold climates because of its
a. sparse hair.
b. large size.
c. stocky appendages.
d. vegetarian diet.
e. thick skin.
Answer: a
58. Why is evaporative cooling used only as a last resort by animals in dry environments?
a. It is ineffective at dissipating heat.
b. Water may be a limiting resource.
c. Sweating requires little energy expenditure.
d. It requires an insulating layer in the skin.
e. Resetting the thermostat is required.
Answer: b
59. When the temperature of the hypothalamus rises, which thermoregulatory response results?
a. Increased metabolic heat production
b. Resetting of the thermostat higher
c. Dilation of blood vessels in the skin
d. Overall increase in body temperature
e. Initiation of shivering movements
Answer: c