Bio 102 Chapter 43 & 44 Questions
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
Osmoconformers
An organism that allows its internal salt concentration to change with the salinity of the surrounding water
Because antigen receptor genes are randomly rearranged, 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?
B and T cells with receptors specific for the body's own molecules are destroyed by apoptosis.
How are cytotoxic T lymphocytes (CTLs) produced?
CD8+ T cells divide and differentiate into a clone of cytotoxic T lymphocytes.
What is the final step in the cell-mediated response to a viral infection?
Cytotoxic T lymphocytes punch holes in the membranes of infected host cells.
Lymphocytes mature in the _____. I) spleen II) thymus III) bone marrow
II and III only
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
________ is a characteristic of adaptive immunity but not innate immunity.
Memory
African lungfish, which are often found in small stagnant pools of fresh water, produce urea as a nitrogenous waste. What is the advantage of this adaptation?
Small stagnant pools do not provide enough water to dilute the toxic ammonia.
The complement system is ________.
a group of antimicrobial proteins that act together in a cascade fashion
Bacteria entering the body through a small cut in the skin _____.
activate a group of proteins called complement.
Freshwater fish excrete nitrogenous wastes as _____.
ammonia
A patient who has a high level of mast cell activity, dilation of blood vessels, and an 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
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
In an HIV cell, what is the function of reverse transcriptase?
catalyzing the formation of DNA from a RNA template
Helper T cells are part of _____.
cell-mediated immune responses
Antidiuretic hormone (ADH) makes the _____ permeable to water.
collecting duct
Which of the following components of the immune system destroys bacteria by punching holes in the wall of the bacteria?
complement protein
T cells of the immune system include _____.
cytotoxic and helper cells
Osmoregulatory adjustment via the atrial natriuretic peptide system can be triggered by ________.
drinking several glasses of water
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
To maintain homeostasis, freshwater fish must ________.
excrete large quantities of water
Nitrogen is absent from
fatty acids
B cells interacting with helper T cells are stimulated to differentiate when _____.
helper T cells release cytokines
Cell-mediated immunity differs from humoral immunity in that _____.
hey respond differently to invaders. 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.
If ATP production in a human kidney was suddenly halted, urine production would _____.
increase, and the urine would be isoosmotic compared to plasma
In a humoral or antibody-mediated immune response, specific B cells are stimulated by helper T cells to transform into plasma cells that secrete antibodies. What would be an important feature added to the plasma cells during this transition process that allows them to better perform their function?
increased rough endoplasmic reticulum for greater antibody production
After drinking alcoholic beverages, increased urine excretion is the result of _____.
inhibited secretion of antidiuretic hormone (ADH)
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
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
An examination of a freshwater fish that died after being placed accidentally in saltwater would likely show that ________.
loss of water by osmosis from cells in vital organs resulted in cell death and organ failure
Processing of filtrate in the proximal and distal tubules _____.
maintains homeostasis of pH in body fluids
Osmoregulation and excretion are _____.
mechanisms that maintain volume and composition of body fluids
CD4 and CD8 are ________.
molecules present on the surface of T cells where they interact with major histocompatibility (MHC) molecules
Under the influence of antidiuretic hormone (ADH), _____ is produced.
more concentrated urine
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
Which of the following would help a virus avoid triggering an effective adaptive immune response? I) having frequent mutations in genes for surface proteins II) building the viral shell from host proteins III) producing proteins very similar to those of other viruses IV) infecting and killing helper T cells
only I, II, and IV
The osmoregulatory/excretory system of a freshwater flatworm is based on the operation of _____.
protonephridia
Unlike an earthworm's metanephridia, a mammalian nephron
receives filtrate from blood instead of coelomic fluid.
Within a differentiated B cell, the rearrangement of DNA sequences between variable regions and joining regions is accomplished by a(n)_____.
recombinase
The osmoregulatory process called secretion refers to the _____.
selective elimination of excess ions and toxins from body fluids
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
Increased antidiuretic hormone (ADH) secretion is likely after _____.
sweating-induced dehydration increases plasma osmolarity
When antibodies bind antigens, the clumping of antigens results from _____.
the antibody having at least two binding regions
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
Which of the following should be the same in identical twins?
the set of major histocompatibility (MHC) molecules produced
For the successful development of a vaccine to be used against a pathogen, it is necessary that ________.
the surface antigens of the pathogen stay the same
Within a normally functioning kidney, blood can be found in _____.
the vasa recta
A primary reason that the kidneys have one of the highest metabolic rates of all body organs is that _____.
they operate an extensive set of active-transport ion pumps
An epitope associates with which part of an antigen receptor or antibody?
variable regions of a heavy chain and light chain combined
leukocyte
white blood cell The leukocytes of the innate immune system are mast cells, macrophages, and neutrophils.
Single-celled Paramecium live in pond water (a hypotonic environment relative to the cytosol). They have a structural feature, a contractile vacuole, which enables them to osmoregulate. If sucrose or saline was added to the pond water in different concentrations (in millimolars, mM), under which conditions would you expect the contractile vacuole to be most active?
0.0 mM sucrose
How do cells involved in the humoral response respond to antigen presentation on the surface of a B cell?
Helper T cells recognize the receptor-antigen complex and cause plasma and memory cells to be produced to then produce antibodies.
Like other osmoregulatory animals that live in marine environments, sharks maintain tissue concentrations of sodium, potassium, and chloride that are hypoosmotic to the seawater. In contrast to the bony marine fishes, however, sharks do not need to drink seawater. Why?
High urea and trimethylamine oxide concentrations keep shark tissues slightly hyperosmotic relative to seawater, so water is absorbed passively.
Which of the following contribute to maintaining the high osmolarity of the renal medulla? I) active transport of salt from the upper region of the ascending limb II) the spatial arrangement of juxtamedullary nephrons III) diffusion of urea from the collecting duct IV) diffusion of salt from the descending limb of the loop of Henle
I, II, and III
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) Antigens from a pathogen bind to antigen receptors on lymphocytes. IV) Lymphocytes specific to antigens from a pathogen become numerous. V) Only memory cells remain.
III → IV → II → I → V
Which protein presents viral antigens on the outer surface of cells?
MHC protein. MHC proteins present antigens on the surface of infected host cells (cell-mediated response) or B cells (humoral response).
Studies of cricket Malpighian tubules revealed that potassium ions accumulated inside the tubule, moving against the potassium concentration gradient. Based on the information, what can you infer about the mechanism of potassium transport?
Movement of potassium into the lumen of the Malpighian tubules is an energy-requiring process.
African lungfish, which are often found in small, stagnant pools of fresh water, produce urea as a nitrogenous waste. What is the advantage of this adaptation?
Small, stagnant pools do not provide enough water to dilute the toxic ammonia
Why are the renal artery and vein critical to the process of osmoregulation in vertebrates?
The renal artery delivers blood with nitrogenous waste to the kidney and the renal vein brings blood with less nitrogenous wastes away from the kidneys
What is the difference between a countercurrent multiplier system, such as the one involving the loop of Henle, and the countercurrent systems that maximize oxygen absorption by fish gills or reduce heat loss in endotherms?
Unlike the other countercurrent systems, a countercurrent multiplier system, such as the one involving the loop of Henle, expends energy in active transport
In which of the following species should natural selection favor the highest proportion of juxtamedullary nephrons?
a mouse species living in a desert
Aldosterone is _____.
a steroid hormone that reduces the amount of fluid excreted in the urine
The structural component(s) of the mammalian nephron where the transcytosis of water increases due to the action of anti-diuretic hormone is/are the _____.
collecting duct
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
Which process in the nephron is LEAST selective?
filtration
Excessive formation of uric acid crystals in humans leads to _____.
gout, a painful inflammatory disease that primarily affects the joints
Excretory organs known as Malpighian tubules are present in _____.
insects
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
The body fluids of an osmoconformer would be ________ with its ________ environment
isoosmotic; seawater
An examination of a marine sea star that had died after it was mistakenly placed in fresh water would likely show that it died because ________.
it was so hypertonic to the fresh water that it could not osmoregulate
Compared to wetland mammals, water conservation in mammals of arid regions is enhanced by having more _____.
juxtamedullary nephrons
Macrophages are _____.
large, phagocytic cells that can leave the circulation and enter the tissues of the body
Urea is produced in the _____.
liver from NH3 and carbon dioxide
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 is the functional unit of a kidney?
nephron
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 region and one V region
Animals have adapted different mechanisms for excreting nitrogenous waste products. Which of the following are selective pressures that likely influence which mechanism an animal uses? I) the amount of water available in the animal's habitat II) the energy needs of the animal III) the temperature of the animal's environment
only I and II
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 proteins can be classified as immunoglobulins? I) T cell receptors II) B cell receptors III) Antigens
only II
Terrestrial animals are _____
osmoregulators that must obtain water from the environment
Mucus occurs in both the respiratory and digestive tracts. What is its main immunological function?
physically trapping of pathogens
Which of the following is crucial to activation of the adaptive immune response?
presentation of MHC (major histocompatibility complex)-antigen complex on a cell surface
Alternative RNA splicing
produces multiple proteins from a single coding gene.
Which of the following would NOT help a virus avoid triggering an adaptive immune response?
producing proteins very similar to those of other viruses
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
The tertiary structure of a protein
relies on multiple weak bonds between side chains
The _____ are the major blood vessels transporting blood to the kidneys.
renal arteries The word "renal" refers to a kidney. Recall that arteries transport blood away from the heart. Renal arteries transport blood to the kidneys.
Urine formed by a kidney collects in the _____ before being drained from the kidney by the _____ and transported to the _____.
renal pelvis ... ureter ...urinary bladder
After blood flow is artificially reduced at one kidney, you would expect that kidney to secrete more of the hormone known as _____.
renin
Jenner's successful use of cowpox virus as a vaccine against the smallpox virus was due to the fact that _____
there are some epitopes (antigenic determinants) common to both pox viruses
Vaccination offers protection against future exposure to pathogens because it ________.
triggers clonal expansion of lymphocytes
The advantage of excreting nitrogenous wastes as urea rather than as ammonia is that ________.
urea is less toxic than ammonia
Which nitrogenous waste has the greatest number of nitrogen atoms?
uric acid
As a result of the non-selectivity of the kidney's filtration of small molecules, _____.
useful substances must be selectively reabsorbed
A strain of fruit fly lacks the ability to produce Dicer-2 protein. You might expect this strain to be more susceptible to ________ infections.
viral
