chapter 43

___ are cells of the mammalian innate immune response that help destroy tumors

Natural killer cells

Which of the following events occurs first when a wound that breaks the skin has occurred

Platelets release proteins that form clots and decrease bleeding

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

You had an adaptive immunity to that virus

The complement system is ________

a group of proteins that act together in a cascade fashion

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 ____

anaphylactic shock immediately following exposure to an allergen

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

antibodies from plasma cells

anaphylactic shock immediately following exposure to an allergen

antihistamines

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

be unable to differentiate and mature T cells

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

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

The role of active cytotoxic T cells is to attack _____

body cells that have been infected

Helper T cells are part of _____

cell mediated immune respsonses

Which of the following components of the immune system destroys cancerous cells by punching holes in plasma membranes and triggering apoptosis

cytotoxic T cells

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 _______

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

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 ________

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

The words "antigen" and "virus" are interchangeable

false

What is the function of reverse transcriptase

host cell membrane

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

injection of antibodies to the toxin

What is the function of reverse transcriptase

making dna from an rna template

The cells and signaling molecules involved in the initial stages of the inflammatory response are ________

mast cells and histamines

_______ is a characteristic of adaptive immunity but not innate immunity

memory

Within a differentiated B cell, the rearrangement of DNA sequences between variable regions and joining regions is accomplished by a(n)____

recombinase

The tertiary structure of a protein

relies on multiple weak bonds between side chains

Immunological memory accounts for _____

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

When antibodies bind antigens, the clumping of antigens results from ____

the antibody having at least two binding regions

Cell-mediated immunity differs from humoral immunity in that ____

they respond differently to invaders

How is a viral antigen, like EBV, recognized by T cells

An antigen fragment is presented within class I MHC to the T cell receptor

Which secretion is not a barrier that prevents pathogens from entering the body

Antigens

Clonal selection is the division of _____ that have been stimulated by binding to an antigen, which results in the production of cloned ____

B cells ... plasma cells and memory cells

What is the role of recombinase in generating lymphocyte diversity

Early in B cell development, recombinase links one light-chain V gene segment to one J gene segment

True or false? The leukocytes of the innate immune system are B cells, macrophages, and neutrophils

False

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 a few days ago and clonal selection has yet to produce plasma cells.

_____ interact with the antigen-class II MHC complex presented by macrophages

Helper T cells

Vertebrate immune cells, which are phagocytic, include ________. I) neutrophils II) macrophages III) dendritic cells IV) natural killer cells

I,II,III

Which of the following are similarities between B cells and T cells? I) They both recognize antigen using immunoglobulin receptors. II) Both B cells and T cells undergo clonal selection after encountering an antigen. III) B cells and T cells both maintain an immunological memory of previously encountered antigens.

II, and III

What major advantage is conveyed by having a system of adaptive immunity

It enables a rapid defense against an antigen that has been previously encountered

How do cells involved in the innate immune response detect the presence of pathogens

Leukocytes recognize unique molecules on pathogens

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

MHC (major histocompatibility complex) proteins

Which of the following cells can engulf a pathogen

Macrophages

Which is a true statement about memory cells

They have a longer lifespan than plasma cells.

Which of the following statements best describes the role of mast cells in the inflammatory response

They release chemicals that dilate blood vessels near the wound site, allowing blood components to enter the region from the bloodstream

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

True

Bacteria entering the body through a small cut in the skin _____

activate a group of proteins called complement

Clonal selection is an explanation for how ________.

an antigen can provoke production of high amounts of specific antibodies

Septic shock, a systemic response including high fever and low blood pressure, is a response to _____

certain bacterial infections

Innate immunity and acquired immunity are both _____

characteristics of all vertebrate animals

Which of the following components of the immune system destroys bacteria by punching holes in the wall of the bacteria?

complement protein

B cells interacting with helper T cells are stimulated to differentiate when _____

helper T cells release cytokines

Inflammatory responses typically include _____

increased activity of phagocytes in an inflamed area

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

inflammatory response

Acidity in human sweat is an example of _____

innate immunity

A nonfunctional CD4 protein on a helper T cell would result in the helper T cell being unable to ________.

interact with a class II MHC-antigen complex

An antigen _____

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

Innate immunity ________

is the first, and most general, mechanism of protection against pathogens

Macrophages are _____.

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

Which of these cells is a phagocytic leukocyte that can engulf a foreign bacterium

macrophage

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 binds to it, subsequently triggering a secondary immune response in the body. Which of the following cell types most accurately describes this cell?

memory cell

Which of these cells is responsible for the rapidity of the secondary immune response

memory cells

CD4 and CD8 ARE _____

molecules present on the surface of T cells where they interact with major histocompatibility (MHC) molecules

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

mutation in the influenza virus is frequent

An immunoglobulin (Ig) molecule, of any class, with regions symbolized as C or V, H or L, has a light chain made up of ________

one C and one V region

Phagocytosis of microbes by macrophages is enhanced by ________. I) the binding of antibodies to the surface of microbes II) antibody-mediated opsonization of microbes III) the release of cytokines by activated B cells

only I and II

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.

only I, II, and IV

What type of immunity is associated with breast feeding

passive immunity

The role of cytotoxic T cells is the secretion of _____, which plays a role in the _____ immune response

perforin ... cell-mediated

Mucus occurs in both the respiratory and digestive tracts. What is its main immunological function

physically trapping pathogens

Naturally acquired passive immunity can result from the _____

placental transfer of antibodies

B cells that have been stimulated by interleukin-2 develop into _____.

plasma cells

Which of these cells produce and secrete antibodies

plasma cells

Alternative RNA splicing

produces multiple proteins from a single coding gene

Yearly vaccination of humans for influenza viruses is necessary because _____

rapid mutation in flu viruses alters the surface proteins in infected host cells

The fact that there are about a million different antigen receptors possible in human B cells is based on _____

recombination of the segments of the receptor DNA that make up the functional receptor genes of differentiated B cells

A bacterium or other particle taken up by phagocytosis is

routed to lysosomes for degradation

Clonal selection and differentiation of B cells activated by antigen exposure leads to the production of _____

short-lived plasma cells that secrete antibodies for the antigen

The genetic material of HIV consists of _____

single-stranded RNA

The switch of one B cell from producing one class of antibody to another class of antibody that is responsive to the same antigen is due to ____

the rearrangement of immunoglobulin heavy-chain C region DNA

The eyes and the respiratory tract are both protected against infections by _____

the secretion of lysozyme onto their surfaces

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

the set of major histocompatibility (MHC) molecules produced

________ are receptor molecules on mammalian cells that recognize macromolecules that are present in or on certain groups of pathogens

toll-like receptors

Vaccination offers protection against future exposure to pathogens because it ________

triggers clonal expansion of lymphocytes