Chapter 16

antigens are? A) specific molecules, or parts of molecules, that the body recognizes as foreign. B) proteins the body produces against invading substances. C) cells that protect the body against invaders. D) proteins on the surface of our cells that pathogens attach to.

Which of the following produces an exogenous antigen? A) a bacterium inside a cell B) a virus inside a cell C) a bacterium outside a cell D) a noninfected human cell

Which of the following statements about lymphocytes is FALSE? A) Once they are mature, they migrate to secondary lymphoid organs. B) B and T lymphocytes can be differentiated under the microscope C) Lymphocytes have integral surface glycoproteins by which they can be recognized. D) The glycoproteins on the surface of a lymphocyte are designated with the prefix CD, for "cluster of differentiation."

The type of immunoglobulin that forms a pentamer is A) IgE. B) IgG. C) IgA. D) IgM.

Which of the following statements concerning the chemical structure of an antibody is FALSE? A) Antibodies are formed of four polypeptide chains. B) Antibodies have two long peptide chains known as heavy chains. C) Antibodies have two short peptide chains known as light chains. D) The heavy and light chains are connected by hydrogen bonds.

The Fc portion of an antibody is formed by A) the lower portions of the heavy chains. B) the upper portions of the heavy chains. C) the upper portions of the light chains. D) the lower portions of the light chains.

The humoral immune response is attributed to the action of A) monocytes. B) T lymphocytes. C) B lymphocytes. D) neutrophils.

Which of the following is NOT considered the function of an antibody? A) Neutralizing bacterial toxins B) Preventing viruses from entering tissue cells C) Direct cell killing through the release of toxic chemicals D) Opsonizing foreign antigen

Secretory IgA antibodies are unique because they A) have unique light chains. B) are Y-shaped molecules. C) are present in the plasma. D) are connected with J chains and short polypeptides to form dimers.

Which of the following function in agglutination? A) IgA antibodies B) IgG antibodies C) IgE antibodies D) IgA and IgG antibodies

Which of the following statements concerning B cell receptors (BCRs) is FALSE? A) They are formed in response to an encounter with an antigen. B) They are complementary in shape to a specific antigenic determinant that they may or may not encounter. C) They are bound to the surface of B lymphocytes and have two antigen-binding sites. D) Each B lymphocyte is randomly generated with antibody variable regions that determine its BCR.

Which of the following statements about T lymphocytes is FALSE? A) There are fewer types of T cell receptors than B cell receptors, and therefore the T lymphocyte cannot react with as many types of antigens. B) T lymphocytes directly attack antigens and produce the cell-mediated immune response. C) T lymphocytes are called such because they mature in the thymus. D) T lymphocytes have TCRs that recognize antigen only if it is bound to MHC.

Which of the following cytokines act as a signal between leukocytes? A) growth factors B) interferons C) interleukins D) tumor necrosis factors

Under normal situations, the lymphocytes do NOT develop an immune response against autoantigens because A) antibodies produced against autoantigens are destroyed. B) they never have binding sites that are complimentary to autoantigens. C) they identify cells with autoantigens as belonging to the body and do not attack them. D) lymphocytes that bind to autoantigens undergo apoptosis.

Which of the following statements about helper T cells is FALSE? A) They secrete messenger proteins called cytokines. B) They are sometimes called T4 cells. C) There are two types: Th1 and Th2. D) They cannot be distinguished from other T lymphocytes.

Major histocompatibility antigens are A) antigens that provoke allergic reactions. B) antigens that must be processed by cells called histiocytes in order to be recognized by the immune system. C) antigens attached to foreign invaders. D) glycoproteins found in the cytoplasmic membranes of most vertebrate animal cells.

Which of the following statements concerning specific immunity is FALSE? A) It is the third line of defense. B) It has memory. C) It changes little with repeated exposure to the same pathogen. D) It is acquired.

The major histocompatibility antigens are coded for by genes on which chromosome number? A) 3 B) 16 C) 6 D) 12

Which of the following molecules would contain T-independent antigens? A) phospholipids B) lipoproteins C) polysaccharides D) glycoproteins

Which of the following statements concerning plasma cells is FALSE? A) They live a long time and function as memory cells. B) They are activated B cells. C) They produce 2000 antibodies per second. D) They secrete antibody molecules with antigen-determining sites that act only against specific antigen determinants.

Enhanced immune responses to subsequent exposures to an antigen to which the body has already been exposed are known as A) third-degree immune responses. B) allergic responses. C) primary immune responses. D) memory responses.

All of the following statements are true of the humoral immune response EXCEPT: A) Is delaying by the memory cell stage B) Most antigens activate B cells without the help of T cells. C) Plasma cells product antibody D) IgA are the first antibodies produced

Cell-mediated immune responses are directed against all of the following EXCEPT: A) Tumor cells B) Extracellular bacteria C) Virus and intracellular fungus D) All of the above

The perforin-granzyme pathway involves A) the production of fever, which kills the pathogen. B) the production of antibodies toward the invading pathogen. C) the synthesis of special cell-killing proteins that act on infected or abnormal cells. D) presenting the foreign antigen to B cells.

Which of the following is not considered part of the immune system? a) Spleen b) Lymph node c) Liver d) Thymus