MICROBIO EXAM #4 KEY
12) Destruction of lymphocytes with self specificity is called ________. A) clonal deletion B) proliferation C) clonal selection D) differentiation E) hypersensitivity
A
13) The molecular fragment on an antigen molecule that a lymphocyte recognizes and responds to is called a(n) ________. A)epitope B)hapten C)antigen binding site D)variable region E)None of the choices are correct.
A
19) Which process involves antibodies covering surface receptors on a virus or toxin molecule thereby disrupting their activity? A)Neutralization B)Opsonization C)Complement fixation D)Agglutination E)Anamnestic response
A
21) The immunoglobulin class that has a dimer form found in mucus, saliva, colostrum, and other body secretions is ________. A)IgA B)IgD C)IgE D)IgG E)IgM
A
31) Which of the following is a special binding substance that enhances immunogenicity and prolongs antigen retention at the injection site? A)Adjuvant B)Booster C)Antibodies to toxin D)Gamma globulin E)"Trojan horse" recombinant vaccine
A
32) Which of the statements below represents the correct order in the development of an immune response? A) Development and clonal deletion; antigen presentation; lymphocyte challenge; lymphocyte response B) Antigen presentation; development and clonal deletion; lymphocyte challenge; lymphocyte response C) Lymphocyte challenge; antigen presentation; development and clonal deletion; lymphocyte response D) Development and clonal deletion; lymphocyte challenge; antigen presentation; lymphocyte response
A
33) Which of the following statements is false regarding the development of adaptive immunity? A)The fourth stage of adaptive immunity involves the production of antibodies by B and T cells against the antigen that initiated the response. B)The second stage in the development of adaptive immunity requires the antigen to be presented to the T cells on the surface of an APC. C)During the third stage in the development of adaptive immunity, B and T cells are challenged by the antigen and respond by differentiating and proliferating. D)The initiation of adaptive immunity involves the development of lymphocytes with the deletion of cells that would react to self molecules.
A
34) The importance of clonal deletion is that ________. A)lymphocytes with receptors that recognize self markers are eliminated to preserve immune tolerance B)worn-out lymphocytes are destroyed to make way for new cells C)lymphocytes that have been activated during antigen exposure are then removed when the individual recovers D)clones of cells that have the same receptor are deleted to avoid redundancy
A
35) Gamma-delta T cells differ from other T cells in that ________. A) they can be directly activated by PAMPs, whereas other T cells have to be presented with the antigen in conjunction with an MHC molecule on an antigen-presenting cell B) they do not have T cell-receptors to bind to antigens C) they do not produce memory cells, unlike the T helper and T cytotoxic cells D) they can react against cancer cells, whereas the other T cells can only target bacteria and viral-infected cells
A
39) Plasma cells ________. A)secrete antibodies B)function in allergic reactions C)directly destroy target cells D)suppress immune reactions E)activate B cells and other T cells
A
41) The region of each antibody molecule where amino acid composition is highly varied from one clone of B lymphocytes to another is the ________. A)variable region B)joining region C)constant region D)light region E)hinge region
A
46) An example of natural active immunity would be ________. A)chickenpox infection followed by lifelong immunity B)chickenpox vaccine, which triggers extended immunity to chickenpox C)giving a person immune serum globulins to chickenpox virus after exposure to the disease D)a fetus acquiring maternal IgG to the chickenpox virus across the placenta E)None of the choices are correct.
A
48) All nucleated cells contain ________. A)class I MHC B)class II MHC C)secretoryantibodies D)IgE receptors E)IgM molecules
A
49) Which statement is true regarding lymphocyte specificity? A)Genetic rearrangement in the DNA that codes for antigen receptors results in up to 10 trillion permutations in the variable regions of B- and T lymphocyte-receptors. B)There is a different gene for every possible antigen that a lymphocyte may encounter. C)B lymphocytes have specificity for a large number of different antigens, however T lymphocytes can recognize only 500 antigens corresponding to the number of gene segments that code for the antigen receptors. D)B- and T cell-receptors are identical and both recognize up to 500 antigens corresponding to the gene segments that code for the antigen receptor variable regions.
A
8) The histocompatibility complex proteins function in ________. A)recognition of self B)antibody proliferation C)B-cell maturation D)T-cell maturation E)None of the choices are correct.
A
18) Which is incorrect about the Fc region of an immunoglobulin? A)Is called the crystallizable fragment B)Forms the antigen binding sites C)Contains an effector molecule that can bind to cells such as macrophages and mast cells D)Contains an effector molecule that can fix complement E)Determines the class to which the immunoglobulin belongs
B
2) Adaptive immunity involves the response of ________. A)skin barriers B)B and T lymphocytes C)lysozyme D)mucous membranes E)interferon
B
20) Which process involves antibodies coating microorganisms in order to facilitate phagocytosis? A)Neutralization B)Opsonization C)Complement fixation D)Agglutination E)Anamnestic response
B
22) ________ are toxic proteins released from the pathogen as it grows. A) Endotoxins B) Exotoxins C) Macrotoxins D) Microtoxins
B
23) An activated T H cell produces ________, which is a growth factor for T helper cells and cytotoxic T cells. A)interleukin-1 B)interleukin-2 C)interleukin-12D)antiserum E)complement
B
29) Killed or inactivated vaccines are prepared by ________. A)removal of virulence genes from the microbe B)treatment with formalin, heat, or radiation C)passage of the pathogen through unnatural hosts or tissue culture D)long-term subculturing of the microbe E)All of thechoices are correct.
B
37) The first stage of developing an adaptive immune response involves ________. A)the presentation of antigens B)lymphocytedevelopment and differentiation C)the challenge of B or T cells by antigens D)the production ofantibodies
B
38) Substances known as _________provoke a specific immune response so discriminating that only a single molecular fragment, called an __________, actually interacts with the lymphocyte's receptor. A) haptens; epitope B) antigens; epitope C) epitopes; antigen D) antigens; immunogen
B
40) Class I MHC genes code for ________. A)certain secreted complement components B)self receptors recognized by T lymphocytes C)all HLA antigens D)receptors located primarily on macrophages and B cells E)All of thechoices are correct.
B
45) Each ________ fragment of an antibody molecule contains the variable regions of a heavy and light chain that folds into a groove for one epitope. A)variable B)Fab C)Fc D)terminal E)hinge
B
15) Which of the following is not a property of B cells? A) Produce plasma cells and memory cells B) Low numbers circulating in the blood C) Require antigen presented with MHC proteins D) Receptors called immunoglobins E) Mature in the bone marrow
C
17) During presentation of APC-bound antigen, macrophages and dendritic cells secrete the cytokine, _______, that activates T helper cells. A)interferon B)interleukin-2 C)interleukin-1 D)histamine E)None of the choices are correct.
C
24) What process provides many B cells and T cells that are activated against specific antigens? A)Antigen expression B)Antibody production C)Clonal expansion D)Antigen presentation E)Opsonization
C
25) The most significant cells in graft rejection are ________. A) helper T cells B) suppressor T cells C) cytotoxic T cells D) delayed hypersensitivity T cells E) natural killer (NK) cells
C
26) Cytotoxic T cells ________. A)are directly activated by antigens B)lack specificity for antigen C)secrete granzymes and perforins that damage target cells D)secrete interleukin-2 to stimulate B and T cells E)All of thechoices are correct.
C
28) An example of artificial passive immunity would be ________. A)chickenpox infection followed by lifelong immunity B)chickenpox vaccine which triggers extended immunity to chickenpox C)giving a person immune serum globulins to chickenpox virus after exposure to the disease D)a fetus acquiring maternal IgG to the chickenpox virus across the placenta E)None of the choices are correct.
C
30) Acellular vaccines and subunit vaccines ________. A)contain modified bacterial exotoxin molecules B)are always genetically engineered C)contain select antigenic components of a pathogen rather than whole cells or viruses D)confer passive immunity E)utilize DNA strands that will produce the antigen
C
50) Choose the statement that best describes the primary action of B cells. A) B cells interact with antigen on antigen-presenting cells B) B cells produce interleukin-2, a lymphocyte growth factor C) B cells divide and differentiate into plasma cells that produce antibody and memory cells. D) B cells become active in cell-mediated immunitygen has entered the system.
C
11) The monomer subunit of immunoglobulin molecules has all the following except ________. A)two identical heavy polypeptide chains B)two identical light polypeptide chains C)disulfide bonds between polypeptide chains D)four antigen binding sites E)a variable and constant region on each polypeptide chain
D
14) The spread of pathogens through the blood and lymph systems that results in a bloodborne systemic infection is called A) bacteremia. B) cancer. C) pathogenesis. D) septicemia. E) complementation
D
27) The benefit of adaptive immunity is the production of _______ that provide long-lasting protection. A)antibodies B)plasma cells C)T helper cells D)memory cells E)phagocytoticcells
D
3) The progeny cells of a B-cell clone are called ________. A)antibodies B)sensitized T cells C)activated macrophages D)plasma cells E)bursa cells
D
42) Properties of effective antigens include all the following except ________. A)are foreign to the immune system B)have molecular complexity C)are large molecules with a minimum molecular weight of 1,000 D)have large polymers made up of repeating subunits E)are cells or large, complex molecules
D
44) The immunoglobulin class that is the only one capable of crossing the placenta is ________. A)IgA B)IgD C)IgE D)IgG E)IgM
D
7) Class II MHC genes code for ________. A)certain secreted complement components B)self receptors recognized by T lymphocytes C)all HLA antigens D)receptors located primarily on macrophages and B cells E)All of thechoices are correct.
D
9) MHC molecules are found on each of the following cells except ________. A)leukocytes B)eosinophils C)epithelial cells D)red blood cells E)islet of Langerhans cells
D
1) A foreign molecule that causes an adaptive immune response is a(n) ________. A)PAMP B)marker C)hapten D)antibody E)antigen
E
10) Lymphocytes ________. A)possess MHC antigens for recognizing self B)have membrane receptors that recognize foreign antigens C)gain tolerance to self by destruction of lymphocytes that could react against self D)develop into clones of B and T cells with extreme variations of specificity E) All of the choices are correct.
E
16) T-cell response to T-cell-dependent antigens requires ________. A) typically a protein antigen B) binding of T-cell to a class II MHC receptor on a macrophage C) binding of T-cell to a site on the antigen D) interleukin-1 activating the T helper cell E) All of thechoices are correct.
E
36) To exhibit high immunogenicity, an antigen would preferably________. A)originate in another organism B)be large in size C)have chemical complexity D)have cell surface markers not recognized asself E)All of the choicesare features of a good antigen.
E
4) Helper T cells ________. A)secrete antibodies B)function in allergic reactions C)directly destroy target cells D)suppress immune reactions E)activate B cells and other T cells
E
43) Antigen-presenting cells ________. A) include dendritic cells B) include macrophages C) engulf and modify antigen to be more immunogenic D) hold and present processed antigen on their cell membrane surface E) All of thechoices are correct.
E
47) Live, attenuated vaccines ________. A)include the Sabin polio vaccine B)include the measles, mumps, rubella vaccine (MMR) C)contain viable microbes that can multiply in the person D)require smaller doses and fewer boosters compared to inactivated vaccines E)All of the choices are correct.
E
5) Lymphocyte maturation involves ________. A)hormonal signals that initiate development B)B cells maturing in bone marrow sites C)T cells maturing in the thymus D)release of mature lymphocytes to begin migration to various lymphoid organs E)All of the choices are correct.
E
6) Cell surface markers involved in immune reactions ________. A) are the result of genetic expression B) function in recognition of self molecules C) receive and transmit chemical messages among other cells of the system D) aid in cellular development E) All of thechoices are correct.
E