Mastering Biology: The Immune System

How does antigen-antibody binding result in destruction of the antigen? Antibodies bind to bacterial DNA and prevent its replication, thereby preventing bacteria from replicating. Antibodies bind the antigen, which then targets the antigen for elimination by innate mechanisms. Antibodies release a destructive enzyme that degrades the enzyme. Antibodies punch holes in bacterial membranes, so that bacteria are destroyed.

Antibodies bind the antigen, which then targets the antigen for elimination by innate mechanisms. When antibodies bind, they target the antigen for elimination by innate mechanisms.

Which of the following cell types is responsible for the humoral immune response? natural killer cells neutrophils B cells macrophages

B cells

Which of the following inflammatory responses is characteristic of only a systemic response? Bacteria and toxins enter the bloodstream, and the white blood cell count increases significantly. Redness, heat, and swelling occur. Blood vessels dilate and become leaky. Body temperature drops.

Bacteria and toxins enter the bloodstream, and the white blood cell count increases significantly. When bacteria and toxins enter the bloodstream, they are carried throughout the body for a systemic effect and elicit a surge in white blood cell production.

Which of the following statements regarding antigens and antibodies is false? Each antibody has only one antigen-binding site. Most antigens are proteins or large polysaccharides on the surfaces of viruses or foreign cells. An antibody usually recognizes and binds to an antigenic determinant. A single antigen may stimulate the immune system to make several distinct antibodies to it.

Each antibody has only one antigen-binding site.

Which of the following statements regarding innate immunity is correct? External barriers such as the skin barrier, exoskeleton, and mucous membranes contribute to innate immunity. The main cells involved in an innate immune response are lymphocytes and antibodies. It is only found in vertebrates. It responds only when the pathogen has previously been encountered.

External barriers such as the skin barrier, exoskeleton, and mucous membranes contribute to innate immunity. In addition to those barriers, there are internal defenses such as phagocytic cells and inflammatory cells that help elicit an innate immune response.

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

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

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? He was probably exposed more than several months ago, antibody production has ceased, and antibodies are no longer detectable. He was probably exposed a few days ago and clonal selection has yet to produce plasma cells. He was probably exposed sometime within the past two weeks, but we don't have enough information to say more.

He was probably exposed a few days ago and clonal selection has yet to produce plasma cells. 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.

What is the key difference between active immunity and passive immunity? In active immunity, a body produces its own antibodies; in passive immunity, a person receives pre-made antibodies. Active immunity refers to the actions that are currently going on in the body, and passive immunity refers to a latent immune response. Passive immunity can be brought on only by artificial means; only the body can produce active immunity. Active immunity does not come from a shot, but passive immunity can.

In active immunity, a body produces its own antibodies; in passive immunity, a person receives pre-made antibodies. Active immunity lasts for a long time because the body will respond to the same antigen again with the same antibodies. Passive immunity lasts only as long as the antibodies last.

How do memory cells differ from effector cells? Memory cells are more numerous. Memory cells are responsible for the primary immune response. Memory cells live longer. Memory cells combat antigens; effector cells do not.

Memory cells live longer. Memory cells do live longer than effector cells.

________ are a component of the immune system that are able to destroy cancer cells by deploying toxins into infected cells as a means of killing them. In this role they are cytotoxic - that is, "cell killing." B cells Antibodies Phagocytes Natural killer cells

Natural killer cells

A virus enters your system and successfully invades and infects a cell. At this point it is vulnerable to recognition or attack by _____. B cells antibodies T cells none of the above

T cells

Which of the following cell types is responsible for the cell-mediated immune response? leukocytes red blood cells B cells T cells

T cells

Which of the following statements about the humoral immune response is true? The humoral immune response defends primarily against bacteria and viruses present in body fluids. The humoral immune response is the result of macrophages producing antibodies. The humoral immune response defends against bacteria and viruses by activating T cells. The humoral immune response plays a major role in protecting the body from cancerous cells.

The humoral immune response defends primarily against bacteria and viruses present in body fluids.

Which is the most likely explanation for why lymph is returned to the circulatory system via veins? The interstitial fluid captured by the lymphatic system is low in oxygen. Lymph organs do not come in contact with arteries. Lymph nodes are located at the junction of lymph vessels and veins. Lymph vessels and veins are similar in structure.

The interstitial fluid captured by the lymphatic system is low in oxygen. If it were returned to arteries, it would reduce the oxygen concentration of arterial blood.

The antigen-binding sites of an antibody molecule are formed from the molecule's variable regions. Why are these regions called variable? These regions can change their shapes to fit different antigens depending on the type of pathogen. These regions change their shapes when they bind to an antigen. The structure of these antibody regions is different from one antibody to the next. The size of these regions vary considerably from one antibody to another.

The structure of these antibody regions is different from one antibody to the next. This structural variety accounts for the diversity of lymphocytes and gives the humoral immune system the ability to react to virtually any kind of antigen.

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

They have a longer lifespan than plasma cells. Plasma cells live only 4-5 days, but memory cells may last for decades.

One kind of vaccine consists of buffered antibodies. antibiotics. B cells. a harmless variant strain of a disease-causing microbe.

a harmless variant strain of a disease-causing microbe.

Antibody molecules may function by causing the crystallization of antigenic particles. destruction of complement proteins. agglutination of viruses or bacteria. solubilization of viruses or bacteria.

agglutination of viruses or bacteria.

Passive immunity can be obtained from __________. an injection of antibodies that recognize invading microbes an injection of inactivated disease-causing microbes a hormone that boosts the immune response white blood cells that fight infection

an injection of antibodies that recognize invading microbes Passive immunity can be transferred artificially by injecting antibodies from an animal that is already immune to a disease into another animal, conferring short-term but immediate protection against that disease.

Upon which of the following is passive immunity dependent? antibodies made by another organism antibody-producing cells from another organism a person's own immune system producing antibodies antigens from a person's own body

antibodies made by another organism

A macromolecule produced in the body that recognizes another molecule as "foreign" to the body is a(n) _____. antigen lymphocyte platelet antibody

antibody An antibody is an antigen-binding immunoglobulin, produced by B cells, that functions as the effector in the immune response.

If you are allergic to grass pollen, that pollen is a(n) _____. antigen antibody antihistamine histamine

antigen Any foreign molecule that elicits a specific immune response, including an allergen, is called an antigen.

In the immune response, the end goal is to disable or kill pathogens that invade the body. But first, antibody proteins or proteins in immune cell membranes must recognize and bind to invaders. This is a challenge, given the vast diversity of pathogens that can infect us. To meet this challenge, immune proteins _____. are flexible: they can alter their shape to bind to nearly any pathogen are diverse: each immune protein can bind to only one or a few pathogens, but immune proteins are tremendously diverse, so the system is likely to possess a "match" to nearly any pathogen are numerous: even though the binding is not specific, the immune system can generally overwhelm pathogens by sheer force of numbers none of the above

are diverse: each immune protein can bind to only one or a few pathogens, but immune proteins are tremendously diverse, so the system is likely to possess a "match" to nearly any pathogen

When a B cell binds to a virus or other pathogen, it _____. kills the pathogen. The B cell is then destroyed by a memory cell. becomes inactive, thereby disabling the pathogen. becomes activated and produces T cells that recognize the pathogen. becomes activated, divides rapidly, and thereby mounts a specialized response against the pathogen.

becomes activated, divides rapidly, and thereby mounts a specialized response against the pathogen.

Clonal selection determines the pool of mature leukocytes that will be stimulated by macrophages. requires the activation of natural killer cells. requires the presence and activation of complement. describes the proliferation of B and T lymphocytes after they have been activated by an antigen.

describes the proliferation of B and T lymphocytes after they have been activated by an antigen.

When a B cell first interacts with its particular antigen, the B cell dies after destroying the antigen. alters the chemical configuration of the antigen. differentiates and develops into a clone of antibody-producing effector cells. engulfs the antigen and digests it.

differentiates and develops into a clone of antibody-producing effector cells.

Which of the following is an immediate effect of histamine release? blocking of a response to ragweed pollen dilation of local blood vessels increase in blood pressure conversion of histamine to histidine

dilation of local blood vessels

Which of the following is part of the inflammatory response? division of B and T lymphocytes to produce an army of effector cells massive production of antibodies constriction of the arterioles dilation of the capillaries

dilation of the capillaries Histamine triggers the dilation and increased permeability of nearby capillaries.

Natural killer cells _____. are part of the complement system begin their lives as neutrophils have short life spans because they self-destruct after engulfing bacteria do not attack microorganisms directly; instead, they destroy virus-infected body cells

do not attack microorganisms directly; instead, they destroy virus-infected body cells This is a description of natural killer cells.

An antigen is a(n) _____. invading virus or bacterium foreign molecule that evokes an immune response protein molecule that helps defend the body against disease type of white blood cell

foreign molecule that evokes an immune response Antigen molecules can belong to any type of organism, or to products of organisms such as pollen or feces.

How can active immunity be obtained? from the bloodstream from an injection of antibodies that recognize invading microbes from the mother's breast milk from a vaccine

from a vaccine Unlike the previous answer choice, a vaccine does not confer immediate immunity by using previously formed antibodies but rather allows the body to form its own to attain immunity.

The thymus is most active during childhood. A child with a malfunctioning thymus will have trouble with __________. leukocyte production humoral immunity humoral and cell-mediated immunity cell-mediated immunity

humoral and cell-mediated immunity The thymus produces T cells, which function primarily in cell-mediated immunity, but they also stimulate B cell action.

Which of the following helps activate our nonspecific (innate) defense system? active immunity inflammation mobilization of erythrocytes passive immunity

inflammation

Chemicals produced by virus-infected cells that alert neighboring cells to prepare a defense are called _____. antigens complement proteins antibodies interferons

interferons Interferon is a chemical messenger of the immune system, produced by virus-infected cells and capable of helping other cells resist the infection.

T and B cells are types of _____. endocrine cells complement cells lymphocytes platelets

lymphocytes The vertebrate body is populated by two main types of lymphocytes: B lymphocytes and T lymphocytes.

Which cell type is responsible for the secondary immune response? plasma cells memory cells T cells B cells

memory cells Memory cells are rapidly activated upon repeated exposure to the same antigen.

Some viral diseases are dangerous only when a person is infected for the first time; subsequent infections produce only mild symptoms or go entirely unnoticed. This pattern can be explained by the action of _____. memory cells that trigger a secondary immune response specific antibodies that remain concentrated in the bloodstream for life after the first infection event memory cells that trigger a primary immune response

memory cells that trigger a secondary immune response

Plasma cells _____. stimulate other lymphocytes attack cells that have been infected by viruses engulf and destroy bacteria and viruses multiply and make antibodies that circulate in blood and lymph

multiply and make antibodies that circulate in blood and lymph B cells that make antibodies are called plasma cells.

Which of these attack cancer cells? neutrophils monocytes memory cells natural killer cells

natural killer cells Natural killer cells attack cancer cells.

Macrophages and neutrophils defend against pathogens by _____. producing antibodies phagocytizing pathogens punching a hole in the plasma membrane of the pathogen, causing the cell to burst secreting lysozyme

phagocytizing pathogens Both macrophages and neutrophils are phagocytic cells.

Which of the following can initiate an inflammatory response? antibodies adrenaline physical injury such as a cut a deficiency in histamine

physical injury such as a cut A physical injury that damages cells can initiate an inflammatory process.

Sam is exposed to a cold virus on Sunday. By Tuesday he has a cough and a congested nose. On Saturday he starts to feel a little better, and antibodies against the cold virus begin to be detectable. What kind of response is this? innate nonspecific primary secondary

primary The primary response is slow to develop.

Antibodies are proteins. carbohydrates. amino acids. lipids.

proteins

Following tissue damage or the entry of microorganisms, an inflammatory response may be initiated by the _____. release of interferon by infected cells increased blood flow to an infected or injured area release of chemicals such as histamine by damaged cells accumulation of phagocytes in an injured area

release of chemicals such as histamine by damaged cells Histamine is one of the most commonly released chemicals.

The main function of the inflammatory response is to initiate the production of antibodies. remove contaminating microorganisms and initiate repair of damaged tissues. initiate T cell-mediated immune responses. initiate the production of killer cells.

remove contaminating microorganisms and initiate repair of damaged tissues.

Functions of the lymphatic system include _____. filtering nitrogenous wastes from the blood producing digestive enzymes and absorbing nutrients return of fluid to the circulatory system and fighting infections transport of oxygen to body tissues

return of fluid to the circulatory system and fighting infections These are the functions of the lymphatic system.

A cell that releases interferon is _____. a macrophage protecting itself against viral infection a cancer cell signaling other cells that it has been infected by a virus

signaling other cells that it has been infected by a virus Interferon is a chemical used in cell-cell communication. It is a signal to other cells that a virus is nearby

Antibodies are _____. cells that engulf and destroy pathogens cells that signal other cells to mount an immune response proteins that are produced by pathogens to get around immune defenses specialized proteins that attach to pathogens and disable them or mark them for destruction by immune cells

specialized proteins that attach to pathogens and disable them or mark them for destruction by immune cells

Which of the following is a lymphatic organ? interstitial fluid blood spleen thymus

spleen The spleen, along with the tonsils, lymph nodes, adenoids, and the appendix, is a lymphatic organ.

To which part of an antigen does an antibody bind? the antigen-binding site the antigenic determinant the entire microbe the interior of the antigen

the antigenic determinant Antigenic determinants are generally small and on the surface of a microbe.

The immune system is initially capable of mounting responses to particular microorganisms because _____. bone marrow cells make different antigen receptors, depending on the invading microorganisms the body contains an enormous diversity of white blood cells, each with a specific kind of antigen receptor white blood cells are able to change their antigen specificity as required to fight infection bone marrow cells determine which type of B and T cells to make

the body contains an enormous diversity of white blood cells, each with a specific kind of antigen receptor The B cells and T cells of the body collectively recognize an effectively infinite number of antigens.

During a secondary immune response, _____. the stricken individual may become ill the generation of effector cells begins with memory cells produced during the primary immune response several days are required from exposure to maximum effector response

the generation of effector cells begins with memory cells produced during the primary immune response The capacity to quickly generate secondary responses is termed "immunological memory."

The first line of defense against infection is _____. the immune system the inflammatory response the skin and mucous membranes antibiotics

the skin and mucous membranes The skin and mucous membranes provide first-line barriers to infection.