BIO 220 - Chapter 43 - HW and Quiz

Inflammatory Response D) Which of the following can engulf a pathogen? A. Macrophages B. Cytokines. C. Platelets. D. Mast cells.

A. Macrophages are leukocytes that can engulf and digest a pathogen.

32) Which of the following pairs of proteins share the most overall similarity in structure? A. B-cell receptors and T-cell receptors B. B-cell receptors and antibodies C. T-cell receptors and antibodies D. antibodies and antigens

B

Clonal Selection video 2.What cellular structure would you predict to be in abundance in macrophages that function in antigen destruction? a) Golgi apparatus b) Lysosomes c) Ribosomes

B

The words "antigen" and "virus" are interchangeable. A. True B. False

B. A virus, like other pathogens, has numerous antigens on its surface, so the words "antigen" and "virus" cannot be used interchangeably.

3) Engulfing-phagocytic cells of innate immunity of vertebrates include ____. I) neutrophils II) macrophages III) dendritic cells IV) natural killer cells A. I and IV B. II and IV C. I, II, and III D. I and III

C

5) Inflammatory responses typically include ___. A. reduced permeability of blood vessels to conserve plasma B. release of substances to decrease the blood supply to an inflamed area C. inhibiting the release of white blood cells from bone marrow D. increased activity of phagocytes in an inflamed area

D

Inflammatory Response A) Which secretion is not a barrier that prevents pathogens from entering the body? A. Ear wax. B. Mucus. C. Lysozyme. D. Antigens.

D. Antigens are foreign molecules that initiate an immune response.

Clonal selection video 3. Which cell type provides long term immunity after a vaccination? a) Plasma cells b) Memory cells

b

26) Lymphocytes mature in the _____. I) spleen II) thymus III) bone marrow A. only II and III B. I, II, and III C. only I and III D. only I and II

A

27) Which of the following statements are fundamental to the clonal-selection theory of how the adaptive immune system functions? I) Each lymphocyte has a unique membrane receptor that recognizes one antigen. II) When the lymphocyte binds an antigen, it is activated and begins dividing to form many identical copies of itself. III) Cloned lymphocytes have slight differences and are selected by the spleen for removal if they do not bind an antigen. IV) Cloned cells descend from an activated lymphocyte and persist even after the pathogen is eliminated. A. only I, II, and IV B. only II and IV C. only I and III D. only II, III, and IV

A

41) Phagocytosis of microbes by macrophages is enhanced by _____. I) the binding of antibodies to the surface of microbes II) antibody-mediated agglutination of microbes III) the release of cytokines by activated B cells A. only I and II B. only II and III C. only I and III D. I, II, and, III

A

47) The number of major histocompatibility (MHC) protein combinations in a given population is enormous. However, a given 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. the MHC proteins are made from several different gene regions that are capable of rearranging in a number of ways C. once a B cell has matured in the bone marrow, it is limited to two MHC response categories D. MHC proteins from one individual can only be of class I or class II

A

61) In a humoral or antibody-mediated immune response, specific B cells are stimulated by Helper T cells to help transform into plasma cells that secrete antibodies. What would be an important feature added to B cells in the transition process? A. Increased rough endoplasmic reticulum in order to have the surface area needed for antibody production B. Duplication of specific gene sequences for the appropriate antibody. C. Duplication of lysosomes in order to store the antibodies before transport.

A

True or false? B cells were originally isolated from the bursa in chickens, and their function is to produce antibodies; T cells were originally isolated from the thymus in mice, and their functions include killing host cells that are being infected with a virus. A. True B. False

A

Which of these cells is a phagocytic leukocyte that can engulf a foreign bacterium? A. macrophage B. cytotoxic T cell C. plasma cell D. helper T cell E. B cell

A. Macrophages are phagocytic leukocytes.

_____ interact with the antigen-class II MHC complex presented by macrophages. A. Helper T cells B. Epithelial cells C. B cells D. Cytotoxic T cells E. Bacterial cells

A. Specific helper T cells recognize specific antigen-class II MHC complexes. The result of this is an activated helper T cell that stimulates both humoral and cell-mediated immune responses.

Inflammation F) Which of the following events occurs first when a wound that breaks the skin has occurred? A. Platelets release proteins that form clots and decrease bleeding. B. Mast cells secrete chemical messengers to regulate blood flow to the wound. C. Macrophages present bacterial proteins as antigens on their plasma membrane. D. Neutrophils secrete substances that degrade bacterial cell walls.

A. The first response to broken skin is the release of clotting proteins from platelets in the bloodstream, which decreases bleeding and helps to seal the wound. Mast cells come in after platelets.

Inflammation G) The site of inflammation may become swollen due to the increased numbers of cells and fluids at the site and painful due to signals from pain receptors. A. True B. False

A. True. The site of inflammation may also become red due to increased blood flow at the site, the inflammatory response continues until all invaders are eliminated and the wound is repaired.

18) Clonal selection and differentiation of B cells activated by antigen exposure leads to the production of ____. A. long-lived erythrocytes that can later secrete antibodies for the antigen B. short-lived plasma cells that secrete antibodies for the antigen C. vast numbers of B cells with random antigen-recognition receptors D. large quantities of the antigen initially recognized

B

A man who has been exposed to the flu virus is tested by his physician. The physician notes that the virus is present but no measurable level of antibodies corresponding to the virus are detected in his body. What might this mean? A. He was probably exposed sometime within the past two weeks, but we don't have enough information to say more. B. He was probably exposed a few days ago and clonal selection has yet to produce plasma cells. C. He was probably exposed more than several months ago, antibody production has ceased, and antibodies are no longer detectable.

B. After first exposure to an antigen, measurable levels of antibodies (produced from plasma cells) are not seen until about a week after exposure. Thus, it is probable that this man was exposed less than a week ago.

Which of the following statements about the clonal-selection theory of immune system function is false? A. Cloned cells persist after the pathogen is eliminated. B. Antigens are recognized by receptor proteins inside the lymphocyte. C. Each lymphocyte recognizes one antigen. D. An activated lymphocyte makes many copies of itself in response to an infection.

B. False, antigens are recognized by receptor proteins on the lymphocyte membrane.

How do cells involved in the humoral response respond to antigen presentation on the surface of a B cell? A. Helper T cells secrete antibodies against the viral antigen. B. Helper T cells recognize the receptor-antigen complex and cause plasma and memory cells to be produced to then produce antibodies. C. Helper T cells divide and produce plasma and memory cells. D. The B cell recognizes the receptor-antigen complex and divides to produce plasma and memory cells.

B. Helper T cells recognize the receptor-antigen complex and activate the B cell, which divides and produces plasma and memory cells.

Which structure is not a component of the adaptive immune system? A. Thymus. B. Tissues. C. Lymphatic ducts. D. Spleen.

B. Lymphocytes of the adaptive immune system do not travel to tissues.

Which protein presents viral antigens on the outer surface of cells? A. B cell receptor. B. MHC protein. C. Antibody. D. T cell receptor.

B. MHC proteins present antigens on the surface of infected host cells (cell-mediated response - b/c they only have MHC I) or B cells (humoral response - b/c they have both MHC I and II - helper T cells).

Inflammatory Response E) Which of the following statements best describes the role of mast cells in the inflammatory response? A. They secrete substances that degrade bacterial cell walls and engulf and digest the invaders. B. They release chemicals that dilate blood vessels near the wound site, allowing blood components to enter the region from the bloodstream. C. They release chemicals that constrict blood vessels at some distance from the wound site. D. They release cytokines to stimulate the release of additional neutrophils and macrophages.

B. Mast cells release chemicals that dilate nearby capillaries, increasing their permeability and allowing blood components to enter the region from the bloodstream, thus causing localized swelling.

Pretest 2) Macrophages are _____. A. cells that induce the lysis of virus-infected body cells B. large, phagocytic cells that can leave the circulation and enter the tissues of the body C. the best defense against parasites D. short-lived cells that self-destruct soon after engulfing foreign invaders E. antigen-presenting cells that originate from neutrophils

B. Once resident in the tissues, macrophages are active phagocytes that capture and digest many microorganisms.

Which of these cells produce and secrete antibodies? A. cytotoxic T cells B. plasma cells C. helper T cells D. bacterial cells E. macrophages

B. Plasma cells are clones of antibody-secreting B cells.

Inflammatory Response B) True or false? The leukocytes of the innate immune response are B cells, macrophages, and neutrophils. A) True B) False

B. The leukocytes of the innate immune system are mast cells, macrophages, and neutrophils.

What is the final step in the cell-mediated response to a viral infection? A. CD8+ T cells are activated. B. Cytotoxic T lymphocytes punch holes in the membranes of infected host cells. C. Macrophages digest viral particles. D. Antibodies coat viral particles.

B. This step causes infected host cells to disintegrate and prevents the virus from spreading to other cells.

Pretest 4) The fact that there are about a million different antigen receptors possible in human B cells is based on _____. A. constant changes in the splicing pattern of receptor genes after the differentiation of the B cell B. recombination of the segments of the receptor DNA that make up the functional receptor genes of differentiated B cells C. temporary changes in the ways that RNA is spliced in the B cells D. having one million different immunoglobulin genes E. the capacity of memory cells to produce antibodies

B. Which variable and which joining segments are recombined in the DNA of the differentiated B cells determined which receptor proteins will be made in that B cell.

10) 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 of the following is a logical explanation for this? A. Your friend had antibodies to that virus. B. Your friend had an autoimmune disorder. C. You had an adaptive immunity to that virus. D. Your friend had allergies.

C

29) Which of the following is a difference between B cells and T cells? A. B cells are activated by free-floating antigens in the blood or lymph. T cells are activated by membrane-bound antigens. B. T cells are produced in the thymus and B cells are produced in the bone marrow. C. One has a major role in antibody production, while the other has a major role in cytotoxicity. D. One binds a receptor called BCR (B-cell receptor), while the other recognizes a receptor called TCR (T-cell receptor).

C

34) Select the pathway that would lead to the activation of cytotoxic T cells. A. cytotoxic T cells → class II MHC molecule-antigen complex displayed → cytokines released → cell lysis B. complement is secreted → B cell contacts antigen → helper T cell activated → cytokines released C. body cell becomes infected with a virus → new viral proteins appear → class I MHC molecule-antigen complex displayed on cell surface D. B cell contact antigen → helper T cell is activated → clonal selection occurs

C

35) 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) Antigenic determinants from pathogens bind to antigen receptors on lymphocytes. IV) Lymphocytes specific to antigenic determinants from pathogens become numerous. V) Only memory cells remain. A. II → I → IV → III → V B. I → III → II → IV → V C. III → IV → II → I → V D. IV → II → III → I → V

C

Clonal Selection video 1.What cellular structure would you predict to be in abundance in plasma cell that function to sythesize large quantities of secreted proteins (antibodies)? a) Antigen receptors b) Lysosomes c) Rough endoplasmic reticulum (ER)

C

Misconception 215) Because antigen receptor genes are randomly arranged, 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. The body's cells are immune to such attack. B. Only a very few lymphocytes produce receptors that attack the body's own molecules, so it's not a problem. C. B and T cells with receptors specific for the body's own molecules are destroyed by apoptosis.

C. As lymphocytes mature in the bone marrow or thymus, their antigen receptors are tested for self-reactivity. Some B and T cells with receptors specific for the body's own molecules are destroyed by apoptosis. The remaining self-reactive cells are typically rendered nonfunctional, leaving only those that react to foreign molecules. Thus, the body normally lacks mature lymphocytes that can react against its own components. Read about self-tolerance.

Which is a true statement about memory cells? A. The first time an antigen is encountered, memory cells become plasma cells. B. They produce antibodies. C. They have a longer lifespan than plasma cells. D. They engulf antigens bound by antibodies.

C. Plasma cells live only 4-5 days, but memory cells may last for decades.

14) The complement system is ____. A. a group of proteins that includes interferons and interleukins B. a set of proteins that act individually to attack and lyse microbes C. a set of proteins involved in innate but not acquired immunity D. a group of antimicrobial proteins that act together in a cascade fashion

D

22) Immunological memory accounts for ____. A. the observation that some strains of the pathogen that causes dengue fever cause more severe disease than others B. the ability of a helper T cell to signal B cells via cytokines C. the human body's ability to distinguish self from non-self D. the ancient observation that someone who had recovered from the plague could safely care for those newly diseased

D

23) Use the following information to answer the question(s) below. An otherwise healthy student in your class is infected with EBV, the virus that causes infectious mononucleosis. The same student had already been infected when she was a child, at which time she had merely experienced a mild sore throat and swollen lymph nodes in her neck. This time, though infected, she does not get sick. The EBV antigen fragments will be presented by the virus-infected cells along with _____. A. class II MHC molecules B. antibodies C. a complement D. class I MHC molecules

D

36) A nonfunctional CD4 protein on a helper T cell would result in the helper T cell being unable to ____. A. stimulate a cytotoxic T cell B. respond to T-independent antigens C. lyse tumor cells D. interact with a class II MHC-antigen complex

D

59) Which of the following is the best definition of autoimmune disease? A. a condition in which B cells and T cells respond independently to antigens and do not interact correctly B. a condition in which the adaptive immune system fails to recognize the second infection by the same antigen C. a condition in which the immune system creates random antibodies without being triggered by an antigen D. a condition in which self molecules are treated as non-self

D

Pretest 3) An antigen ____. A. could be an invading bacterium B. is a protein molecule that helps defend the body against disease C. induces development of white blood cells in the bone marrow D. is a foreign molecule that evokes a specific response by a lymphocyte E. is a protein attacked by an invading microorganism

D. Antigen molecules can be part of any type of organism. Antigen molecules could also be a part of a product of an organism such as pollen or feces (allergens).

How are cytotoxic T lymphocytes (CTLs) produced? A. Plasma cells secrete cytotoxic T lymphocytes. B. Helper T cells divide and differentiate into cytotoxic T lymphocytes. C. B cells divide and differentiate into cytotoxic T lymphocytes. D. CD8+ T cells divide and differentiate into cytotoxic T lymphocytes.

D. CD8+ T cells divide and differentiate into a clone of cytotoxic T lymphocytes.

Which of these cells is responsible for the rapidity of the secondary immune response? A. cytokines B. macrophages C. cytotoxic T cells D. memory cells E. plasma cells

D. Memory cells are responsible for the rapidity of the secondary immune response and for long-term immunity.

Inflammatory Response C) How do cells involved in the innate immune response detect the presence of pathogens? A. Antibodies bind to the pathogens. B. Leukocytes recognize the secretions from a pathogen. C. Leukocytes recognize the entire pathogen. D. Leukocytes recognize unique molecules on pathogens.

D. Pattern-recognition receptors on the leukocytes recognize and bind to unique molecules on the pathogens, such as the amino acid N-formylmethionine in bacteria. This receptor binding leads to the activation of the innate immune response.

The role of cytotoxic T cells is the secretion of _____, which plays a role in the _____ immune response. A. interleukin-2 ... humoral B. antibodies ... humoral C. antibodies ... antibody-mediated D. perforin ... cell-mediated E. perforin ... humoral

D. Perforin causes the lysis of pathogen-infected body cells; it is a component of the cell-mediated immune response.

Clonal selection is the division of _____ that have been stimulated by binding to an antigen, which results in the production of cloned _____. A. helper T cells ... plasma cells B. B cells ... macrophages C. T cells ... B cells D. B cells ... plasma cells and memory cells E. macrophages ... B cells and T cells

D. The antigen-selected proliferation of B cells produces clones of plasma cells and memory cells.

Pretest 6) Cell-mediated immunity differs from humoral immunity in that ____. A. a subsequent secondary immune response can occur in humoral immunity 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. they respond differently to invaders

E. Humoral immunity is a function of B cells and antibody production, whereas cell-mediated immunity is a function of the activation of cytotoxic T cells.

B cells that have been stimulated by interleukin-2 develop into _____. A. antigens B. macrophages C. helper T cells D. cytotoxic T cells E. plasma cells

E. Plasma cells develop from B cells that have been stimulated by interleukin-2 secreted by helper T cells.