chapter 43 & 44

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

To answer the following question, assume that the number of B cells producing a specific antibody is proportional to the concentration of that antibody. On day 16, assume that one out of every 105 B cells in the body is specific for antigen A and that the antibody concentration on day 16 is about 2 × 101. Calculate the frequency of B cells specific for antigen A on day 36 if the antibody concentration on day 36 is about 8 × 103. (For practice doing calculations with proportions, try this exercise. For practice doing calculations with numbers written in scientific notation, try this exercise.)

1 in 250

Your cousin works in the sugar cane fields of Nicaragua. Which of the following will he have to have before being cleared to harvest?

A blood or urine test to measure kidney function.

You study genetics of tiger sharks and find the same general genetic makeup in great white sharks. Which of the following did you discover?

A large proportion of their genes are involved in antibody-mediated immunity.

Which of the following citizens of Chichigalpa would be most likely to suffer from CKDu?

A man who works in the sugar cane fields.

Which of the following is true?

A person vaccinated for measles can get the disease, though it is not likely.

Which of the following statements best describes the actions of the hormone ADH on the nephron?

ADH causes the collecting duct to increase water reabsorption by the surrounding tissue under conditions of dehydration.

Select the correct statement about the immune system.

All antigen receptors produced by a single B cell or T cell are identical and bind to the same epitope.

Select the correct statement about osmoregulation.

All osmoconformers are marine animals.

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.

How does an antihistamine reduce allergy symptoms?

An antihistamine blocks receptors for inflammatory chemicals released from granules within mast cells.

Which of the following statements about the clonal-selection theory of immune system function is false?

Antigens are recognized by receptor proteins inside the lymphocyte.

Examine the figure of a human nephron. Where and when does osmolarity of the filtrate increase?

As the filtrate moves down the descending limb of the loop of Henle

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.

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

How are cytotoxic T lymphocytes (CTLs) produced?

CD8+ T cells divide and differentiate into cytotoxic T lymphocytes.

Why are children more likely to pick up germs in public places?

Children tend to be more tactile, and may not wash their hands as often as they should.

Which of the following would be the best experimental design for a study looking at the effect of hand-washing on the incidence of acquiring an infectious disease?

Choose a setting where a large number of people consistently spend time, such as an office building. Randomly assign everyone to one of two groups. Ask one group to wash their hands every hour, and ask the other group to avoid washing their hands except when truly necessary. Compare the incidence of infectious disease between the two groups over a period of months or years.

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.

Which of the following is true?

Dialysis is used to manage kidney disease.

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.

You are an epidemiologist studying CKDu. To further research into this disease, in what two countries should you look to study?

El Salvador and Sri Lanka

What is dialysis?

Filtering of the blood.

Which of the following would be the best experimental design for a study looking at the risk of getting an infectious disease from using public transportation?

Follow a very large set of people in order to reduce the effect of socioeconomic status. One group is comprised of people who frequently use public transportation, and the other group never uses public transportation. Compare the incidence of infectious disease between the two groups. Collect data without telling the participants too much about the study, so that they do not alter their normal behaviors.

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

Helper T cells

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.

What is the driving force for the filtration of blood by the renal corpuscle?

Higher pressure in glomerular capillaries than in the surrounding Bowman's capsule.

When it comes to applying these findings to humans, which of the following is most promising?

Humans have counterparts to two of these shark genes.

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

I, II, and III

Which of the following is true regarding the 2014-2015 measles outbreak in the U.S.?

It occurred throughout the entire United States.

When it comes to eradicating polio, which of the following is the biggest obstacle?

Locating the last infected individuals.

In which region of the nephron is a steep osmotic gradient created?

Loop of Henle.

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

An immune response to a tissue graft will differ from an immune response to a bacterium because _____.

MHC molecules of the donor may stimulate rejection of the graft tissue, but bacteria lack MHC molecules

Which protein presents viral antigens on the outer surface of cells?

MHC protein.

Use the following information to answer the question(s) below. An otherwise healthy student in your class was infected with EBV (the virus that causes infectious mononucleosis) when she was a child, at which time she had merely experienced a mild sore throat and swollen lymph nodes in her neck. When she is exposed to EBV again later in life, she does not get sick or have any symptoms of mononucleosis. Which of the following statements explains why your class mate does not exhibit symptoms of EBV infection?

Memory T cells quickly recognized the virus upon the second exposure and destroyed the virally infected cells.

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.

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

Natural killer cells

As of the writing of this article, which of the following appears to be the cause of CKDu?

No cause has been determined.

Select the correct statement about osmolarity.

Osmolarity measures the moles of solute per liter of solution.

Which of the following is associated with increased cancer rates in humans?

Overexpression of legumain and Bag1

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.

Which of the following represents the correct sequence of flow through the nephron?

Renal corpuscle > proximal tubule > loop of Henle > distal tubule > collecting duct

Which regions of the nephron function independently of hormonal control for the most part?

Renal corpuscle, proximal tubule, and loop of Henle.

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.

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.

You have a child and decide to not have him vaccinated. Who is most likely to support you in this decision?

The National Vaccine Information Center.

In the mock-up of an airplane cabin, there were heated yellow bags where people would normally sit. Why?

The bags are added to create an experimental model that would be most similar to an actual plane full of people.

You just received a freshwater aquarium as a gift and decide to add more fish. When you get to the pet store, you find that the most beautiful fish are saltwater animals, but you decide to buy them anyway. What will happen when you put your expensive saltwater fish in your freshwater aquarium?

The cells of the fish will take up too much water, and the fish will die.

Which route of water gain makes up a much larger share of the total in a kangaroo rat as compared to a human?

The kangaroo rat gains a much larger share of its water from metabolism than a human does.

Which of the following statements is true?

The kidneys are paired organs that regulate water and electrolyte balance in terrestrial vertebrates.

If recent trends continue, which of the following will happen?

The mortality rate for chronic kidney disease will decrease.

Select the correct statement describing the osmolarity of mammalian urine.

The osmolarity of mammalian urine may vary over time.

Salmon eggs hatch in fresh water. The fish then migrate to the ocean (a hypertonic solution) and, after several years of feeding and growing, return to fresh water to breed. How can these organisms make the transition from fresh water to ocean water and back to fresh water?

The salt transport mechanisms of the gill epithelia change during migration.

Studies of cricket Malpighian tubules revealed that potassium ions accumulated inside the tubule, moving against the potassium concentration gradient. How would you expect the movement of water to be influenced by the distribution of potassium ions?

There would be a net movement of water into the lumen of the tubules.

What role do transport epithelia play in osmoregulation of marine fish with bony skeletons?

They are involved in excretion of excess salt.

Which of the following is a general property of epithelial cells?

They display an apical and a basal surface that define cell polarity.

Which is a true statement about memory cells?

They have a longer lifespan than plasma cells.

Which of the following appears to have heavily impacted sharks' ability to heal quickly?

They have had a long time to adapt.

Which structure is not a component of the adaptive immune system?

Tissues

You are a pediatrician in Southern California. Who are you likely to have the hardest time convincing to have their child vaccinated?

Wealthy parents that lead an all-natural lifestyle.

Filtration takes place in the structure labeled ________.

a

Which arrow indicates the direction of a gradient of increasing solute concentration in the interstitial fluid surrounding a nephron?

a

Which of these binds to receptor molecules on the host cell membrane?

a

Which of the following is the best definition of autoimmune disease?

a condition in which self molecules are treated as nonself (loss of self-tolerance)

If you are hiking through the desert for several days, one would pack which of the following to ensure proper hydration?

a drink with a combination of water and electrolytes

The complement system is ________.

a group of proteins that act together in a cascade fashion

Which of the following animals generally has the lowest volume of urine production?

a marine bony fish

In which of the following species should natural selection favor the highest proportion of juxtamedullary nephrons?

a mouse species living in a desert

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

activate a group of proteins called complement

Which of these is not part of insect immunity?

activation of natural killer cells

Glucose is removed from filtrate by _____.

active transport

The results shown in the graphs support the hypothesis that ________.

adding the defensin gene to such mutants protects them from death by bacterial infection

Which setting has the shortest time span for air refreshment - in other words, which setting has the most frequent air exchange with fresh air?

airplane cabin

Freshwater fish excrete nitrogenous wastes as _____.

ammonia

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

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

antigens

A patient complaining of watery, itchy eyes and sneezing after being given a flower bouquet as a birthday gift should first be treated with _____.

antihistamines

Filtrate is formed as fluid is forced through the walls of the glomerulus and, initially, collects in the structure indicated by the letter

b

Selective secretion of toxins and drugs takes place in the structure labeled ________.

b

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

Which of these is reverse transcriptase?

c

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

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

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

The outer part of the kidney is the _____.

cortex

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

cytotoxic T cells

T cells of the immune system include _____.

cytotoxic and helper cells

You are a nephrologist. A 72 year old female patient presents with advanced kidney failure and you recommend the standard treatment. What did you suggest?

dialysis

The high osmolarity of the renal medulla is maintained by all of the following except

diffusion of salt from the descending limb of the loop of Henle.

The structure labeled ________ can be influenced by hormones to change the concentration of the urine.

e

Which of these is the viral genome?

e

The increasing use of which of the following has helped drive up production of sugar cane in Nicaragua?

ethanol

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

To maintain homeostasis, freshwater fish must ________.

excrete large quantities of water

Nitrogen is absent from

fatty acids

The movement of substances out of the glomerulus and into Bowman's capsule is referred to as _____.

filtration

Which process in the nephron is LEAST selective?

filtration

Which process in the nephron is least selective?

filtration

Low selectivity of solute movement is a characteristic of _____.

filtration from the glomerular capillaries

In osmosis, water undergoes net diffusion to an area of lower

free water concentration

In an airplane, from whom are you most likely to acquire a cold or flu virus?

from a sick person sitting next to you

Excessive formation of uric acid crystals in humans leads to _____.

gout, a painful inflammatory disease that primarily affects the joints

What is the source of a viral envelope?

host cell membrane

Checkpoint inhibitors work by utilizing which body system?

immune

You are a geneticist interested in finding similar genes in great white sharks. Which gene type will such genes be associated with?

immune

Which of the following characteristics describes the thin segment of the ascending limb of the loop of Henle?

impermeable to H2O, permeable to NaCl

If ATP production in a human kidney was suddenly halted, urine production would _____.

increase, and the urine would be isoosmotic compared to plasma

Inflammatory responses typically include _____.

increased activity of phagocytes in an inflamed area

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

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

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

Acidity in human sweat is an example of _____.

innate immunity

An appropriate group of animals to examine to observe a Malpighian tubule would be _____

insects

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

An antigen _____

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

The transfer of fluid from the glomerulus to Bowman's capsule ________.

is mainly a consequence of blood pressure in the capillaries of the glomerulus

Innate immunity ________.

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

Compared to the seawater around them, most marine invertebrates are ________.

isoosmotic

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

An excretory system that is partly based on the filtration of fluid under high hydrostatic pressure is the _____.

kidneys of vertebrates

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

Which of the following is characteristic of juxtamedullary nephrons?

long loop of Henle

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

Ammonia is likely to be the primary nitrogenous waste in living conditions that include _____.

lots of fresh water flowing across the gills of a fish

Vaccination increases the number of

lymphocytes with receptors that can bind to the pathogen.

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

macrophage

Processing of filtrate in the proximal and distal tubules _____.

maintains homeostasis of pH in body fluids

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

mast cells and histamines

Osmoregulation and excretion are _____

mechanisms that maintain volume and composition of body fluids

________ is a characteristic of adaptive immunity but not innate immunity.

memory

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

Your friend has a genetic defect that prevents him from repairing DNA damaged during mitosis. What is this called?

mismatch repair deficiency

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

As filtrate moves down the loop of Henle, the surrounding interstitial fluid becomes _____ concentrated than the filtrate, so _____ leaves the filtrate.

more..water

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

mutation in the influenza virus is frequent

What is the basic functional unit of the kidney?

nephron

Which of these is the functional unit of a kidney?

nephron

Which column represents the dependent variable, and which axis should it be plotted on?

number of parasites on y-axis

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

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

only I and II

Which of the following statements about epitopes are correct? I) B-cell receptors bind to epitopes. II) T-cell receptors bind to epitopes. III) There can be 10 or more different epitopes on each antigen.

only I, II, and III

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. IV) Cloned cells descend from an activated lymphocyte and persist even after the pathogen is eliminated.

only I, II, and IV

Lymphocytes mature in the _____. II) thymus III) bone marrow

only II and III

Terrestrial animals are _____.

osmoregulators that must obtain water from the environment

What type of immunity is associated with breast feeding?

passive immunity

A human who has no access to fresh water but is forced to drink seawater instead will ________.

passively excrete excess water in order to remove the high concentration of ingested salt

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

perforin ... cell-mediated

Your uncle has kidney disease and his doctor recommends dialysis. He opts for treatment he can do at home. What did he choose?

peritoneal dialysis

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

physically trapping of 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

Which of the following is the least likely substance to be found in the glomerular filtrate?

plasma proteins

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

In animals, nitrogenous wastes are produced mostly from the catabolism of _____.

proteins and nucleic acids

The osmoregulatory/excretory system of a freshwater flatworm is based on the operation of _____.

protonephridia

Double-stranded viral DNA is incorporated into a host cell as a _____.

provirus

Yearly vaccination of humans for influenza viruses is necessary because _____.

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

Materials are returned to the blood from the filtrate by which of the following processes?

reabsorption

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 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

Birds, insects, and many reptiles excrete nitrogenous waste in the form of uric acid, which _____.

reduces water loss compared to other nitrogenous wastes, but requires more metabolic energy to produce

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

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

Birds secrete uric acid as their nitrogenous waste because uric acid _____.

requires little water for nitrogenous waste disposal, thus reducing body mass

A bacterium or other particle taken up by phagocytosis is

routed to lysosomes for degradation.

The movement of substances from the blood into the proximal tubule is known as _____.

secretion

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

Which of these is reabsorbed from filtrate?

sodium chloride glucose water amino acids all of these

If a person is prone to allergies, what treatment could redirect their immune response to help prevent future allergic reactions?

stimulating activated B cells to switch antibody production from class IgE to class IgM

Increased antidiuretic hormone (ADH) secretion is likely after _____.

sweating-induced dehydration increases plasma osmolarity

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

The force driving simple diffusion is _____, while the energy source for active transport is _____.

the concentration gradient; ATP

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 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

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

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

Cell-mediated immunity differs from humoral immunity in that _____.

they respond differently to invaders

Unlike most bony fishes, sharks maintain body fluids that are isoosmotic to seawater, so they are considered by many to be osmoconformers. Nonetheless, these sharks osmoregulate at least partially by _____.

tolerating high urea concentrations that are balanced with internal salt concentrations to seawater osmolarity

You have a young child. You can get them vaccinated for all of the following diseases except?

tonsilitis

What is the major method of transmission of infectious disease when using public transportation?

touching surfaces that sick people have touched

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.

true

The most abundant solute in urine is _____.

urea and other nitrogenous waste

As a result of the non-selectivity of the kidney's filtration of small molecules, _____.

useful substances must be selectively reabsorbed

An epitope associates with which part of an antigen receptor or antibody?

variable regions of a heavy chain and light chain combined

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

Which of the following cancer patients is likely to fair the best after being treated with checkpoint inhibitors?

A patient with a tumor that produces PD-L1.

Each person makes more than 1 million different B cell antigen receptors and more than 10 million different T cell antigen receptors. How is such diversity in antigen receptors generated?

By combining variable elements, the immune system assembles many different receptors from a much smaller collection of parts.

According to the Centers for Disease Control and Prevention, what is happening with condom use among gay men in the United States?

It is declining.

You are a volunteer for Doctors Without Borders. Finding which of the following in a Nigerian village would be most likely to lead you to thinking it is a polio outbreak?

Three recently paralyzed patients.

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.

Aldosterone is _____.

a steroid hormone that reduces the amount of fluid excreted in the urine

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

antibodies from plasma cells

In which section of the nephron does the filtrate have a higher osmolarity than the blood when it enters and lower osmolarity than the blood when it leaves?

ascending limb of the loop of Henle

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

be unable to differentiate and mature T cells

Which of the following are similarities between B cells and T cells? 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.

both II and III

Which column represents the independent variable, and which axis should it be plotted on?

day on x-axis

Terrestrial organisms lose water through evaporation. In what ecosystem might an entomologist find a good study organism to examine the prevention of water loss?

desert

The loop of Henle dips into the renal cortex. This is an important feature of osmoregulation in terrestrial vertebrates because _____.

differential permeabilities of ascending and descending limbs of the loop of Henle are important in establishing an osmotic gradient

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

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

false

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

false

Choose a pair that correctly associates the mechanism for osmoregulation or nitrogen removal with the appropriate animal.

flame bulb: flat worm

Within a normally functioning kidney, blood can be found in _____.

the vasa recta

Which nitrogenous waste has the greatest number of nitrogen atoms?

uric acid

Which of the following individuals should be prescribed PrEP?

A 28 year old sexually promiscuous gay man who is HIV negative.

Which of the following would be the most beneficial in the eradication of polio in Africa?

A decrease in the amount of civil and military unrest.

Which of the following statements is not true?

A lymphocyte has receptors for multiple different antigens.

You are the CEO of the vaccine company Pfizer. Your company is pursuing the creation of a new polio vaccine. Which of the following people will likely be most helpful to you?

A virologist, specializing in viruses.

Antidiuretic hormone (ADH) and the renin-angiotensin-aldosterone system (RAAS) work together in maintaining osmoregulatory homeostasis through which of the following ways?

ADH regulates the osmolarity of the blood by altering renal reabsorption of water, and the RAAS maintains the osmolarity of the blood by stimulating both Na+ and water reabsorption.

If current prescription rates for PrEP hold, which of the following will be true?

About 50% of the prescriptions will be written for men.

Assuming this recent outbreak is controlled, where are the last two areas that polio is known to remain?

Afghanistan and Pakistan

Which statement best describes the difference between responses of effector B cells (plasma cells) and those of cytotoxic T cells?

B cells secrete antibodies against a pathogen; cytotoxic T cells kill pathogen-infected host cells.

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.

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

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

I, II, 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

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.

Which of the following cells can engulf a pathogen?

Macrophages

Which of the following is a positive aspect of using the prescribed prophylactic treatment Truvada?

Most private insurance companies cover the cost.

Which route of water loss makes up a much larger share of the total in a kangaroo rat as compared to a human?

The kangaroo rat loses a much larger share of its water through evaporation (during gas exchange) than a human does.

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.

You are a molecular pathologist and have been asked to look at the tumor from a lung cancer patient. Which of the following is most likely?

There were more than fifty DNA mutations in the tumor.

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.

If trends of the last decade continue, which of the following will happen to newly diagnosed cases of AIDS in the United States over the next ten years?

They will stay about the same.

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

Toll-like receptors

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.

Natural selection should favor the highest proportion of juxtamedullary nephrons in which of the following species?

a mouse species living in a desert

Clonal selection is an explanation for how ________.

an antigen can provoke production of high amounts of specific antibodies

Antidiuretic hormone (ADH) makes the _____ permeable to water.

collecting duct

You are an oncologist. Six members of a family test positive for Lynch syndrome. Which of the following types of cancer are they most likely to get?

colorectal

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

complement protein

In humans, the transport epithelial cells in the ascending loop of Henle _____.

have plasma membranes of low permeability to water

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

helper T cells release cytokines

The ability of some viruses to remain inactive (latent) for a period of time is exemplified by _____.

herpes simplex viruses (oral or genital) whose reproduction is triggered by physiological or emotional stress in the host

Developing bird embryos excrete most of their nitrogenous waste as uric acid because ________.

it has a low solubility in water and is less toxic to the embryo than other forms of waste

Compared to wetland mammals, water conservation in mammals of arid regions is enhanced by having more _____.

juxtamedullary nephrons

Among the following choices, the most concentrated urine is excreted by _____.

kangaroo rats

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 IV) infecting and killing helper T cells

only I, II, and IV

Which of the following proteins can be classified as immunoglobulins? II) B cell receptors

only II

The fluid with the highest osmolarity is ________.

seawater in a tidal pool

Urea is _____.

the primary nitrogenous waste product of humans

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

Which of the following contributes most significantly to the kidney's high energy expenditure?

transport of NaCl in the thick segment of the ascending limb of the loop of Henle

Vaccination offers protection against future exposure to pathogens because it ________

triggers clonal expansion of lymphocytes

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

The advantage of excreting nitrogenous wastes as urea rather than as ammonia is that ________.

urea is less toxic than ammonia

Which of the following is reabsorbed in the proximal tubule, leading to a reduction in the overall filtrate volume?

water and solutes