Chapter 43 Questions

Question 1

A boy falls while riding his bike. A scrape on his hand almost immediately begins to bleed and becomes red, warm, and swollen. What response is occurring?

a. inflammatory response
b. adaptive immune response
c. lytic response
d. autoimmune response

Answer 1

a. inflammatory response

Question 2

You and a friend were in line for a movie when you noticed the woman in front of you sneezing and coughing. Both of you were equally exposed to the woman’s virus, but over the next few days, only your friend acquired flu-like symptoms and was ill for almost a week before recovering. Which one of the following is a logical explanation for this?

a. You had an immunological memory of that virus.
b. Your friend had allergies.
c. Your friend had antibodies to that virus.
d. Your friend had an autoimmune disorder.

Answer 2

a. You had an immunological memory of that virus.

Question 3

A newborn who is accidentally given a drug that destroys the thymus would most likely ___.

a. be unable to differentiate and mature T cells
b. have a reduced number of B cells and be unable to form antibodies
c. be unable to genetically rearrange antigen receptors
d. lack innate immunity

Answer 3

a. be unable to differentiate and mature T cells

Question 4

Immunological memory accounts for ___.

a. the human body’s ability to distinguish self from non-self
b. the ability of a helper T cell to signal B cells via cytokines
c. the ancient observation that someone who had recovered from the plague could safely care for those newly diseased
d. the observation that some strains of the pathogen that causes dengue fever cause more severe disease than others

Answer 4

c. the ancient observation that someone who had recovered from the plague could safely care for those newly diseased

Question 5

An otherwise healthy student in your class was infected wth EBV (the virus that causes infectious mononucleosis) when she was a child, at which time she had merely experienced a mild sore throat and swollen lymph nodes in her neck. When she is exposed to EBV again later in life, she does not get sick or have any symptoms of mononucleosis.
Which of the following statements explains why your class mate does not exhibit symptoms of EBV infection?
a. Complement proteins effectively controlled the EBV during the second infection.
b. Her innate immune response was better at recognizing the EBV antigen during the second infection.
c. Memory T cells quickly recognized the virus upon the second exposure and destroyed the virally infected cells.
d. She was likely infected with a weaker strain of EBV during her second exposure.

Answer 5

c. Memory T cells quickly recognized the virus upon the second exposure and destroyed the virally infected cells.

Question 6

Vaccination offers protection against future exposure to pathogens because it ___.

a. enhances the activity of macrophages
b. triggers clonal expansion of lymphocytes
c. promotes inflammation
d. stimulates the complement system

Answer 6

b. triggers clonal expansion of lymphocytes

Question 7

___ is a characteristic of adaptive immunity but not innate immunity.

a. Lysozyme
b. Memory
c. Interferons
d. Inflammation

Answer 7

b. Memory

Question 8

A certain cell type has existed in the blood and tissue of its vertebrate host’s immune system for over 20 years. One day, it recognizes a newly arrived antigen and bids to it, subsequently triggering a secondary immune response in the body. Which of the following cell types most accurately describes this cell?

a. thyroid cell
b. memory cell
c. plasma cell
d. macrophage

Answer 8

b. memory cell

Question 9

Which of the following statements about epitopes are correct?
I. B cell receptors bind to epitopes.
II. T cell receptors bind to epitopes.
III. There can be 10 or more different epitopes on each antigen.
IV. There is a one-to-one correspondence between antigen and epitope.
a. only II, III, and IV
b. only I and III
c. only I, II, and III
d. only II and IV

Answer 9

c. only I, II, and III

Question 10

Select the pathway that would lead to the activation of cytotoxic T cells.

a. body cell becomes infected with a virus -> new viral proteins appear -> class I MHC molecule-antigen complex displayed on cell surface
b. complement is secreted -> B cell contacts antigen -> helper T cell activated -> cytokines released
c. cytotoxic T cells -> class II MHC molecule-antigen complex displayed -> cytokines released -> cell lysis
d. B cell contact antigen -> helper T cell is activated -> clonal selection occurs

Answer 10

a. body cell becomes infected with a virus -> new viral proteins appear -> class I MHC molecule-antigen complex displayed on cell surface

Question 11

Arrange in the correct sequence these components of the mammalian immune system as it first responds to a pathogen.
I. Pathogen is destroyed.
II. Lymphocytes secrete antibodies.
III. Antigens from a pathogen bind to antigen receptors on lymphocytes.
IV. Lymphocytes specific to antigens from a pathogen become numerous.
V. Only memory cells remain.
a. IV -> II -> III -> I -> V
b. III -> IV -> II -> I -> V
c. I -> III -> II -> IV -> V
d. II -> I -> IV -> III -> V

Answer 11

b. III -> IV -> II -> I -> V

Question 12

An individual who has been bitten by a poisonous snake that has a fast-acting toxin would likely benefit from ___.

a. injection of interleukin-1
b. injection of interferon
c. vaccination with a weakened form of the toxin
d. injection of antibodies to the toxin

Answer 12

d. injection of antibodies to the toxin

Question 13

For the successful development of a vaccine to be used against a pathogen, it is necessary that ___.

a. the major histocompatibility (MHC) molecules are heterozygous
b. all of the surface antigens on the pathogen be identified
c. the surface antigens of the pathogen stay the same
d. the pathogen has only one epitope

Answer 13

c. the surface antigens of the pathogen stay the same

Question 14

The number of major histocompatibility (MHC) protein combinations possible in a given population is enormous. However, an individual in that diverse population has a far more limited array of MHC molecules because ___.

a. each of the MHC genes has a large number of alleles, but each individual only inherits two for each gene
b. MHC proteins from one individual can only be of class I or class II
c. once a B cell has matured in the bone marrow, it is limited to two MHC response categories
d. the MHC proteins are made from several different gene regions that are capable of rearranging in a number of ways

Answer 14

a. each of the MHC genes has a large number of alleles, but each individual only inherits two for each gene

Question 15

A bone marrow transplant may not be appropriate from a given donor (Jane) to a given recipient (Jane’s cousin, Bob), even though Jane has previously given blood for one of Bob’s needed transfusions because ___.

a. for each gene, there is only one blood allele but many tissue alleles
b. even though Jane’s blood type is a match to Bob’s her major histocompatibility (MHC) proteins may not be a match
c. a blood type match is less stringent than a match required for transplant because blood is more tolerant of change
d. Jane’s MHC class II genes are not expressed in bone marrow

Answer 15

b. even though Jane’s blood type is a match to Bob’s her major histocompatibility (MHC) proteins may not be a match

Question 16

An immune response to a tissue graft will differ from an immune response to a bacterium because ___.

a. a bacterium cannot escape the immune system by replicating inside normal body cells
b. MHC molecules of the donor may stimulate rejection of the graft tissue, but bacteria lack MHC molecules
c. the tissue graft, unlike the bacterium, is isolated from the circulation and will not enter into an immune response
d. the graft will stimulate an autoimmune response in the recipient

Answer 16

b. MHC molecules of the donor may stimulate rejection of the graft tissue, but bacteria lack MHC molecules

Question 17

Which of the following is crucial to activation of the adaptive immune response?

a. presentation of MHC (major histocompatibility complex)-antigen complex on a cell surface
b. memory cells
c. activation of complement proteins
d. phagocytosis of antibody-antigen complex by macrophages in the blood

Answer 17

a. presentation of MHC (major histocompatibility complex)-antigen complex on a cell surface

Question 18

A patient who has a high level of mast cell activity, dilation of blood vessels, and acute drop in blood pressure is likely suffering from ___.

a. a typical skin allergy (contact dermatitis) that can be treated by antihistamines
b. anaphylactic shock immediately following exposure to an allergen
c. an autoimmune disease
d. an organ transplant, such as a skin graft

Answer 18

b. anaphylactic shock immediately following exposure to an allergen

Question 19

The ability of some viruses to remain inactive (latent) for a period of time is exemplified by ___.

a. the virus that causes a form of the common cold, which recurs in patients many times in their lives
b. influenza, a particular strain of which returns every 10-20 years
c. Kaposi’s sarcoma, which causes a skin cancer in people in people with AIDS but rarely in those not infected by HIV
d. herpes simplex viruses (oral or genital) whose reproduction is triggered by physiological or emotional stress in the host

Answer 19

d. herpes simplex viruses (oral or genital) whose reproduction is triggered by physiological or emotional stress in the host

Question 20

If a person is prone to allergies, what treatment could redirect their immune response to help prevent future allergic reactions?

a. reducing the number of helper T cells in the body
b. reducing the number of cytotoxic cells
c. stimulating activated B cells to switch antibody production from class IgE to class IgM
d. blocking the antigen recognition sites of IgM antibodies

Answer 20

c. stimulating activated B cells to switch antibody production from class IgE to class IgM

Question 21

Which of the following in vertebrates has the same function as hemocytes in insects?

a. Toll-like receptor
b. interferon
c. complement system
d. neutrophils
e. mast cells

Answer 21

d. neutrophils

Question 22

The specificity of a particular antibody for its target epitope is determined by _____.

a. the variable regions
b. the constant regions
c. the light chains
d. the heavy chains
e. the transmembrane region

Answer 22

a. the variable regions

Question 23

The exceptionally large diversity of antigen receptors found on B cells and T cells is mostly the result of _____.

a. random mutations
b. clonal selection
c. alternate splicing
d. recombinase activity
e. gene duplication

Answer 23

d. recombinase activity

Question 24

What is true of a secondary immune response?

1. It is brought about by memory cells.
2. It is less effective than a primary immune response.
3. It includes a humoral response but not a cell-mediated response.
4. After it occurs, the immune system can only respond to reinfection with the same antigen by mounting another primary immune response.
   a. 1 only
   b. 1 and 2
   c. 1 and 3
   d. 2, 3, and 4
   e. 1, 2, and 3

Answer 24

a. 1 only

Question 25

Consider this graph of the immune response to antigens A and B. If you expose this individual to antigen C on day 56, what do you expect to see?
Figure.
a. 10^3 antibodies to B on day 61
b. 10^4 antibodies toA on day 61
c. 10 antibodies to C on day 61
d. 10 antibodies to C on day 67
e. 10 antibodies to A on day 67

Answer 25

d. 10 antibodies to C on day 67

Question 26

Which of the following is required to activate a cell-mediated or humoral immune response to a foreign molecule?

a. cytokines secreted by helper T cells
b. perforins secreted by cytotoxic T cells
c. granzymes secreted by cytotoxic T cells
d. antibodies secreted by plasma cells
e. complement proteins secreted by the liver

Answer 26

a. cytokines secreted by helper T cells

Question 27

Which defensive chemical is improperly matched with its function?

a. perforins—lysis
b. antibodies—pathogen neutralization
c. histamines—dilate capillaries
d. cytokines—immune cell stimulation
e. lysozymes—cause fevers

Answer 27

e. lysozymes—cause fevers

Question 28

What is the correct sequence in which the following occur during a primary humoral immune response?

1. B cell activation
2. helper T cell activation
3. plasma cell differentiation and proliferation
4. antibody secretion
5. presentation of antigen on class II MHC proteins
   a. 5, 2, 1, 4, 3
   b. 4, 5, 2, 1, 3
   c. 5, 1, 2, 3, 4
   d. 4, 5, 3, 1, 2
   e. 5, 2, 1, 3, 4

Answer 28

e. 5, 2, 1, 3, 4

Question 29

What is “matched” between donor tissue and recipient in order to increase the likelihood of a successful transplantation?

a. antigens
b. allergens
c. Toll-like receptors
d. MHC proteins
e. antibodies

Answer 29

d. MHC proteins

Question 30

Which of the following is characteristic of herpesvirus infections?

a. increased antigenic variation
b. latency
c. direct attack on the immune system
d. cause liver cancer
e. not affected by stress

Answer 30

b. latency

Question 31

Barrier defenses are important for protection against infections by all of the following except _____.

a. intracellular parasites
b. fungi
c. bacteria
d. viruses

Answer 31

a. intracellular parasites

Question 32

A synonym for an effector B cell is a(an) _____ cell.

a. plasma
b. memory
c. tolerant
d. immune
e. suppressor

Answer 32

a. plasma

Question 33

Which of the following is a correct statement about hypersensitivity reactions?

a. Hypersensitivity reactions involve antibodies of the IgG class.
b. Platelets in connective tissues may be recruited.
c. Hypersensitivity reactions are exaggerated allergicreactions.
d. An acute response is called toxic shock syndrome.
e. Histamine drugs may diminish symptoms.

Answer 33

c. Hypersensitivity reactions are exaggerated allergicreactions.

Question 34

One reason that misinformation about vaccine safety and disease susceptibility is a societal concern is that _____.

a. unvaccinated people carry smallpox
b. side effects of vaccination are increasing
c. declines in vaccination rates may result in disease outbreaks
d. diseases like measles kill nearly five million people annually
e. theme parks may harbor resistant strains

Answer 34

c. declines in vaccination rates may result in disease outbreaks

Question 35

Innate immunity and acquired immunity are both _____.

a. based on the trapping of microbes by mucus
b. characteristics of all vertebrate animals
c. dependent on tears, saliva, and mucous secretions that contain lysozyme, an enzyme that digests bacterial cell walls
d. dependent exclusively on cell-mediated responses
e. dependent on surface secretions from sebaceous and sweat glands, which give the skin an acidic pH that is unfavorable for bacterial colonization

Answer 35

b. characteristics of all vertebrate animals

Question 36

Macrophages are _____.

a. the best defense against parasites
b. short-lived cells that self-destruct soon after engulfing foreign invaders
c. antigen-presenting cells that originate from neutrophils
d. large, phagocytic cells that can leave the circulation and enter the tissues of the body
e. cells that induce the lysis of virus-infected body cells

Answer 36

d. large, phagocytic cells that can leave the circulation and enter the tissues of the body

Question 37

An antigen _____.

a. is a foreign molecule that evokes a specific response by a lymphocyte
b. could be an invading bacterium
c. induces development of white blood cells in the bone marrow
d. is a protein molecule that helps defend the body against disease
e. is a protein attacked by an invading microorganism

Answer 37

a. is a foreign molecule that evokes a specific response by a lymphocyte

Question 38

The role of active cytotoxic T 
cells is to attack \_\_\_\_\_.
a. circulating antibodies
b. extracellular viruses and bacteria
c. circulating proteins
d. complement proteins
e. body cells that have been infected

Answer 38

e. body cells that have been infected

Question 39

Cell-mediated immunity differs from humoral immunity in that _____.

a. they respond differently to invaders
b. a humoral response is mounted more quickly
c. cell-mediated immunity is longer lasting
d. clonal selection occurs only in cell-mediated immunity
e. a subsequent secondary immune response can occur in humoral immunity

Answer 39

a. they respond differently to invaders

Question 40

Helper T cells are part of _____.

a. innate immunity
b. the complement system
c. a group of phagocytic white blood cells
d. cell-mediated immune responses
e. the first cells to bind to antigens

Answer 40

d. cell-mediated immune responses

Question 41

Extracellular pathogens such as viruses and bacteria in body fluids are attacked by _____.

a. antibodies from plasma cells
b. cytotoxic T cells
c. helper T cells
d. complement proteins
e. antigens

Answer 41

a. antibodies from plasma cells

Question 42

Tissues are immunogically “typed” before an organ transplant to make sure that the donor and recipient match as closely as possible in their _____.

a. MHC (major histocompatibility complex) proteins
b. T cells
c. antibodies
d. histamines
e. B cells

Answer 42

a. MHC (major histocompatibility complex) proteins

Question 43

A primary reason for needing a new vaccine for influenza each year is that _____.

a. the first infection with influenza weakens the immune system
b. mutation in the influenza virus is frequent
c. the influenza virus might proliferate in different tissues during each subsequent year, and immune memory is limited to those tissues initially infected
d. immunity typically disappears one month after recovery from a disease
e. influenza is a disease that causes the apoptosis of all memory cells

Answer 43

b. mutation in the influenza virus is frequent

Question 44

Which of these is not part of insect immunity?

a. activation of natural killer cells
b. a protective exoskeleton
c. phagocytosis by hemocytes
d. production of antimicrobial peptides
e. enzyme activation of microbe-killing chemicals

Answer 44

a. activation of natural killer cells

Question 45

An epitope associates with which part of an antigen receptor or antibody?

a. variable regions of a heavy chain and light chain combined
b. the light-chain constant regions only
c. the disulfide bridge
d. the tail
e. the heavy-chain constant regions only

Answer 45

a. variable regions of a heavy chain and light chain combined

Question 46

Which statement best describes the difference between responses of effector B cells (plasma cells) and those of cytotoxic T cells?

a. B cells carry out the cell-mediated response; cytotoxic T cells carry out the humoral response.
b. B cells respond the first time a pathogen is present; cytotoxic T cells respond subsequent times.
c. B cells confer active immunity; cytotoxic T cells confer passive immunity.
d. B cells secrete antibodies against a pathogen; cytotoxic T cells kill pathogen-infected host cells.

Answer 46

d. B cells secrete antibodies against a pathogen; cytotoxic T cells kill pathogen-infected host cells.

Question 47

Which of the following statements is not true?

a. An antigen can have different epitopes.
b. A lymphocyte has receptors for multiple different antigens.
c. An antibody has more than one antigen-binding site.
d. A liver or muscle cell makes one class of MHC molecule.

Answer 47

b. A lymphocyte has receptors for multiple different antigens.

Question 48

Which of the following should be the same in identical twins?

a. the set of immune cells eliminated as self-reactive
b. the set of antibodies produced
c. the susceptibility to a particular virus
d. the set of T cell antigen receptors produced
e. the set of MHC molecules produced

Answer 48

e. the set of MHC molecules produced

Question 49

Vaccination increases the number of

a. macrophages specific for a pathogen.
b. lymphocytes with receptors that can bind to the pathogen.
c. MHC molecules that can present an antigen.
d. different receptors that recognize a pathogen.
e. epitopes that the immune system can recognize.

Answer 49

b. lymphocytes with receptors that can bind to the pathogen.

Question 50

Which of the following would not help a virus avoid triggering an adaptive immune response?

a. producing proteins very similar to those of other viruses
b. infecting cells that produce very few MHC molecules
c. infecting and killing helper T cells
d. having frequent mutations in genes for surface proteins
e. building the viral shell from host proteins

Answer 50

a. producing proteins very similar to those of other viruses

Question 51

Each person makes more than 1 million different B cell antigen receptors and more than 10 million different T cell antigen receptors. How is such diversity in antigen receptors generated?

a. Genes for individual antigen-binding sites have a very high rate of mutation, generating great diversity.
b. A large percentage of the vertebrate genome is devoted to genes for individual antigen-binding sites.
c. By combining variable elements, the immune system assembles many different receptors from a much smaller collection of parts.

Answer 51

c. By combining variable elements, the immune system assembles many different receptors from a much smaller collection of parts.

Question 52

Select the correct statement about the immune system.

a. Adaptive immunity is characteristic of invertebrates and vertebrates.
b. Antibodies are secreted by T cells.
c. All antigen receptors produced by a single B cell or T cell are identical and bind to the same epitope.

Answer 52

c. All antigen receptors produced by a single B cell or T cell are identical and bind to the same epitope.

Question 53

How does an antihistamine reduce allergy symptoms?

a. An antihistamine blocks receptors for inflammatory chemicals released from granules within mast cells.
b. An antihistamine binds pollen antigens, preventing them from provoking an allergic reaction.
c. An antihistamine kills mast cells, blocking an allergic reaction.

Answer 53

a. An antihistamine blocks receptors for inflammatory chemicals released from granules within mast cells.

Question 54

Because antigen receptor genes are randomly rearranged, some immature lymphocytes produce receptors specific for epitopes on the organism’s own molecules. Why doesn’t the immune system attack these molecules on the body’s cells and tissues?

a. Only a very few lymphocytes produce receptors that attack the body’s own molecules, so it’s not a problem.
b. B and T cells with receptors specific for the body’s own molecules are destroyed by apoptosis.
c. The body’s cells are immune to such attack.

Answer 54

b. B and T cells with receptors specific for the body’s own molecules are destroyed by apoptosis.

Question 55

Which of these is not part of insect immunity?

a. enzyme activation of pathogen-killing chemicals
b. activation of natural killer cells
c. phagocytosis by hemocytes
d. production of antimicrobial peptides

Answer 55

b. activation of natural killer cells

Question 56

An epitope associates with which part of an antigen receptor or antibody?

a. the tail
b. the heavy-chain constant regions only
c. variable regions of a heavy chain and light chain combined
d. the light-chain constant regions only

Answer 56

c. variable regions of a heavy chain and light chain combined

Question 57

Which statement best describes the difference between responses of effector B cells (plasma cells) and those of cytotoxic T cells?

a. B cells confer active immunity; cytotoxic T cells confer passive immunity.
b. B cells respond the first time a pathogen is present; cytotoxic T cells respond subsequent times.
c. B cells secrete antibodies against a pathogen; cytotoxic T cells kill pathogen-infected host cells.
d. B cells carry out the cell-mediated response; cytotoxic T cells carry out the humoral response.

Answer 57

c. B cells secrete antibodies against a pathogen; cytotoxic T cells kill pathogen-infected host cells.

Question 58

Which of the following statements is not true?

a. An antibody has more than one antigen-binding site.
b. A lymphocyte has receptors for multiple different antigens.
c. An antigen can have different epitopes.
d. A liver or muscle cell makes one class of MHC molecule.

Answer 58

b. A lymphocyte has receptors for multiple different antigens.

Question 59

Which of the following should be the same in identical twins?

a. the set of antibodies produced
b. the set of MHC molecules produced
c. the set of T cell antigen receptors produced
d. the set of immune cells eliminated as self-reactive

Answer 59

b. the set of MHC molecules produced

Question 60

Vaccination increases the number of

a. different receptors that recognize a pathogen.
b. lymphocytes with receptors that can bind to the pathogen.
c. epitopes that the immune system can recognize.
d. MHC molecules that can present an antigen.

Answer 60

b. lymphocytes with receptors that can bind to the pathogen.

Question 61

Which of the following would not help a virus avoid triggering an adaptive immune response?

a. having frequent mutations in genes for surface proteins
b. infecting cells that produce very few MHC molecules
c. producing proteins very similar to those of other viruses
d. infecting and killing helper T cells

Answer 61

c. producing proteins very similar to those of other viruses