Microbiology ~ Unit 4 (chapters 13, 14, 15, and 19)

animal viruses ____________ -can be grown in bacterial cell cultures -can only be grown in animal cells

can only be grown in animal cells

effector lymphocyte

expresses specific traits that help eliminate invaders

the population of microbes that routinely grow on the body surfaces is the _____________ microbiota, or flora

normal

an epidemic of typhoid fever in a Swiss ski resort occurred only in ______, because the locals rarely drink water, preferring wine instead -locals -tourists

tourists

true or false: because of the widespread use of antimicrobial drugs in hospitals, many organisms causing nosocomial infections have become resistant to these medications

true

the amino acid sequence of the end of the "arms" of different antibody molecules is ________ -conserved, thus providing the "red flag" for other immune system components to eliminate the antigen -variable, thus providing the basis for antibody specificity to antigens -variable, thus providing the "red flag" for other immune system components to eliminate the antigen -conserved, thus providing the basis for antibody specificity to antigens

variable, thus providing the basis for antibody specificity to antigens

replication of single-stranded DNA viruses is quite similar to that of double-stranded DNA viruses, except that ___________ -the single-stranded DNA molecule must be reverse transcribed into cDNA -a copy of RNA must be synthesized to serve as the template for the synthesis of double-stranded DNA -a complement to the single-stranded DNA molecule must be synthesized -the single-stranded DNA forms hairpin loops, making a complementary strand unnecessary

-a complement to the single-stranded DNA molecule must be synthesized

when a macrophage receives assistance from a helper T cell in the form of cytokines, it _______ -activates more potent destructive mechanisms for the cell, enhancing its antigen clearing capacity -is induced to undergo apoptosis -shuts down destruction of the antigens it has ingested via phagocytosis -becomes much more efficient at ingesting microbes

-activates more potent destructive mechanisms for the cell, enhancing its antigen clearing capacity

the primary adaptive immune response ___________ -is very fast, since it's the first time the pathogen is "seen" by the system -can take a week or longer to become fully protective -will be identical in nature to the secondary response to the same antigen at a later date -produces "memory" to be used later on in subsequent exposures

-can take a week or longer to become fully protective -produces "memory" to be used later on in subsequent exposures

humans have been enormously successful in eliminating or reducing the occurrence of certain diseases through efforts in _______ -improved sanitation -reservoir and vector control -vaccination -deforestation -antibiotic treatment -robotic surgery

-improved sanitation -reservoir and vector control -vaccination -antibiotic treatment

primary response traits

-initially lacks affinity maturation; formed near the end of the response -usually IgM in nature -initially lacks class switching; formed near the end of the response -slow to develop, taking 10-14 days

a T-cell receptor (TCR) is _________ -is similar (but not identical) in function to a B cell receptor -is found on the surface of T cells -a terminal cassette repeat structure -only recognizes antigen that is presented by another cell -is found on the surface of all lymphocytes

-is similar (but not identical) in function to a B cell receptor -is found on the surface of T cells -only recognizes antigen that is presented by another cell

a healthcare-associated infection (HAI) is one acquired in a _________ -long-term care facility -urgent care facility -health club -hospital -doctor's office

-long-term care facility -urgent care facility -hospital -doctor's office

T-independent antigens _________ -might be lipid variants such as LPS -are protein molecules -activate B cells, but these B cells require assistance from a cell other than a T cell to become completely activated -might be repeating polymers of carbohydrates -can activate B cells without T cell assistance -possesses long stretches of repeating subunits

-might be lipid variants such as LPS -might be repeating polymers of carbohydrates -can activate B cells without T cell assistance -possesses long stretches of repeating subunits

transmission of pathogens via direct contact __________ -often involves organisms with a low infectious dose -can be as simple as a handshake or as intimate as sexual intercourse -is unavoidable -usually involves organisms with a high infectious dose -may be reduced by routine handwashing

-often involves organisms with a low infectious dose -can be as simple as a handshake or as intimate as sexual intercourse -may be reduced by routine handwashing

a problem encountered in primary cultures derived from normal tissue cells is that cells will ____________ -divide rapidly and indefinitely -only divide a limited number of times

-only divide a limited number of times

which facts best support the position that viruses are not living organisms? -viruses are inert outside of a host -viruses cannot reproduce on their own -viruses are very small -viruses are agents of disease -viruses are not prokaryotic

-viruses are inert outside of a host -viruses cannot reproduce on their own

which of the following statements about viruses are true -viruses contain RNA or DNA but not both -the viral capsid is composed of carbohydrates -the viral capsid is composed of protein -viruses contain both DNA and RNA in one capsid

-viruses contain RNA or DNA but not both -the viral capsid is composed of protein

Stages of lymphocyte development

1. immature lymphocyte 2. naive lymphocyte 3. activated lymphocyte 4. effector lymphocyte

all of the following are usually true of secondary response EXCEPT -IgM is not the main antibody used -IgM is the main antibody produced -affinity maturation has already occurred -memory cells are already in place from the previous exposure to the same antigen -class switching has already occurred

IgM is the main antibody produced

the opportunistic pathogen __________ causes many nosocomial infections, thrives in hospital sinks, respirators, and toilets, and grows readily in nutrient-poor environments -staphylococcus aureus -pseudomonas aeruginosa -enterococcus faecalis -escherichia coli

P. aeruginosa

outbreak

a group of cases occurring during a brief time interval

in a case-control study, which characteristics should the controls share with the cases -disease symptoms -age -gender -socioeconomic status

age gender socioeconomic status

a plasma cell is ___________ -a fully differentiated T lymphocyte -an antibody producing descendent of a B cell -a participator in cell-mediated immunity -the form of B cell ready to be activated by antigen -a memory cell for the humoral immune responses

an antibody producing descendent of a B cell

epidemic

an unusually large number of cases

pandemic

an unusually large number of cases occurring on several continents

before a B cell undergoing antigen-induced activation can proliferate, it must usually get help from __________ -another type of lymphocyte-a helper T cell (Th) -neutrophils that have initially responded to the antigen in the infected area -cytotoxic T cells -other B cells in the area also undergoing activation

another type of lymphocyte--a helper T cell

the term "Fab region" stands for "fragment of __________ binding region"

antigen

lymph fluid contains foreign _____________ and other material passes through lymph nodes, stimulating a response from B and T cells

antigens

neutrophils _________ -are usually the first cell type recruited to a damaged area -are a type of lymphocyte -are involved in adaptive immune responses -take up residence in tissues in case of infection in the area

are usually the first cell type recruited to a damaged area

in order to infect an animal cell, viruses must ______________ -attach to receptors on the host cytoplasmic membrane -modify host cell receptors into glycoproteins -inject their DNA through the host cell membrane -inject their RNA through the host cell membrane

attach to receptors on the host cytoplasmic membrane

hematopoietic stem cells can be found in the _____________ -bone marrow -brain -muscle tissue -lungs -liver

bone marrow

replication of double-stranded DNA viruses ______________ -is very different from replication of single-stranded viruses -involves a reverse transcriptase enzyme -follows the central dogma of molecular biology

follows the central dogma of molecular biology

naive lymphocyte

mature, but has not encountered antigen previously

a ____________ is an animal virus genome residing silently in a host cell genome.

provirus

the purpose of the hematopoietic stem cells is to give rise to _______________ -epithelial cells -skeletal muscle cells -red blood cells -white blood cells

red blood cells, white blood cells

in addition to helper T cells and cytotoxic T cells, a third type of T cells that have recently been described are the ___________ T cells

regulatory

the single most important measure for preventing the spread of infectious disease is considered to be _________ -annual vaccinations -regular use of antibiotics -routine handwashing -quarantine of sick patients

routine handwashing

airborne transmission (a type of indirect transmission)

small droplets from which fluid evaporates to create droplet nuclei

clostridium tetani, the causative agent of tetanus, a disease that infects humans, is found widespread in soils. therefore, the reservoir for this organism is ________ -animals -soils -humans

soils

true or false: some pathogens are more likely to cause disease than others when transmitted to a new host

true

use of a urinary catheter _________ the risk of developing a urinary tract infection -increases -decreases

increases

__________ contact involves transfer of pathogens via inanimate objects such as doorknobs, drinking glasses, or clothing, otherwise known as fomites

indirect

what are the basic functions of helper T cells -induction of apoptosis in infected self cells -activation of macrophages -direct lysis of extracellular bacteria -coordination of activities of B cells, macrophages, and other T cells -activation of B cells

-activation of macrophages -coordination of activities of B cells, macrophages, and other T cells -activation of B cells

the study of viruses is important because ____________. -viruses cause all known human diseases -bacteriophages play a significant ecological role in reducing bacterial populations in nature -viruses play a role in bacterial conjugation -viruses can be a vehicle for horizontal gene transfer in bacteria -there are many medically important viruses that cause disease

-bacteriophages play a significant ecological role in reducing bacterial populations in nature -viruses can be a vehicle for horizontal gene transfer in bacteria -there are many medically important viruses that cause disease

as the dendritic cells that have engulfed antigen migrate into lymph nodes, they -begin to produce costimulatory molecules that will help activate naive T cells -produce CD4 molecules to attract helper T cells -work on processing the antigen to load its peptides into MHC molecules -produce CD8 molecules to attract cytotoxic T cells -eliminate the antigen

-begin to produce costimulatory molecules that will help activate naive T cells -work on processing the antigen to load its peptides into MHC molecules

TCR (T cell receptor) traits

-composed of 2 polypeptide chains -has only one peptide binding site -each chain in the receptor has a single variable and single constant region domain

BCR (B cell receptor) traits

-composed of 4 polypeptide chains -has 2 peptide binding sites -light chains have a single variable and single constant region domain, while heavy chains have a single variable and multiple constant region domains

the increase in temperature from a moderate fever helps the body fight an infection by ____________ -enhancing the inflammatory response -reducing the rate of respiration and thus conserving energy -slowing or preventing the growth of microbes that have lower optimum temperatures -decreasing rates of human enzymatic reactions -enhancing phagocytic activity and the multiplication of lymphocytes

-enhancing the inflammatory response -slowing or preventing the growth of microbes that have lower optimum temperatures -enhancing phagocytic activity and the multiplication of lymphocytes

protection of lysogens from infection by the same phage is called ________________ -lysogenic conversion -reverse transcription -immunity to superinfection -adaptive immunity

-immunity to superinfection

functions and characteristics of regulatory T cells include __________ -preventing manifestation of autoimmune diseases -activation assistance of other T cell groups -a lack of a TCR -suppression of activation of immune system responses against "self" -possession of a TCR just like other T cells group

-preventing manifestation of autoimmune diseases -suppression of activation of immune system responses against "self" -possession of a TCR just like other T cells groups

Which of the following are non-cellular infectious agents? -fungi -bacteria -protozoa -prions -viroids -viruses

-prions -viroids -viruses

what events occur as a result of memory B cells being activated as part of the secondary response -quick differentiation into plasma cells -class switching -induction of apoptosis -proliferation -a second round of affinity maturation

-quick differentiation into plasma cells -proliferation -a second round of affinity maturation

regarding animal viruses, which of the following statements are true -some viruses require more than one host receptor for attachment -the normal function of host membrane receptors is for virus adsorption -blocking a host receptor with a drug would prevent a virus from infecting that cell -viruses use their spikes to attach to host cell receptors

-some viruses require more than one host receptor for attachment -blocking a host receptor with a drug would prevent a virus from infecting that cell -viruses use their spikes to attach to host cell receptors

memory cells can speed up a secondary response because __________ -there are many of them -their enzymes work faster than those of normal naive lymphocytes -class switching has already occurred, so the response is already fine-tuned for the antigen in question -class switching hasn't taken place yet, so responses can still be fine-tuned for the new antigen -affinity maturation has already taken place, increasing the ability to bind antigen

-there are many of them -class switching has already occurred, so the response is already fine-tuned for the antigen in question -affinity maturation has already taken place, increasing the ability to bind antigen

retroviruses may lead to latent infections because ____________ -they can integrate a DNA copy of their genome into the host chromosome -their genome is a mix of RNA and DNA, both of which a host cell also contains -their RNA can suppress all normal host cell activities -they can integrate their RNA genome into the host chromosome

-they can integrate a DNA copy of their genome into the host chromosome

in the case of retroviruses, reverse transcriptase uses a viral RNA template to synthesize DNA, which can then be __________ -transcribed and translated to form new virions -transported to the cytoplasmic membrane for export to neighboring cells -translated directly to form multiple new viruses -integrated into a host cell chromosome where it remains latent

-transcribed and translated to form new virions -integrated into a host cell chromosome where it remains latent

secondary response traits

-usually NOT IgM in nature -faster to develop due to performed memory cells -strong levels of affinity maturation already in place -class switching has already taken place

which is most important for attachment of a virus to a host cell? -viral specificity for host receptors -number of genes carried by the virus -viral shape and size

-viral specificity for host receptors

human body temperature is kept around 37ºC by a temperature-regulation center in the _____________ -brain -heart -digestive tract -lungs

brain

antibiotics disrupt the normal microbiota and can predispose a person to infections caused by ____________ -lactobacillus species growing in the intestinal tract -candida albicans growing in the vagina -lactobacillus species growing in the vagina -clostridium difficile growing in the intestine

candida albicans growing in the vagina clostridium difficile growing in the intestine

sporadic

cases occur only from time to time

the spread of an infectious disease follows a series of steps called the _______ of infection

chain

antibody-antigen binding can activate the complement cascade via the ____________ -mannose-binding lectin pathway -alternative pathway -classical pathway

classical pathway

an epidemic in which the patients were all exposed to a single source of the infectious agent is called a ____________-_________ epidemic

common-source

endemic

constantly present in a given population

_________ cells, a type of antigen-presenting cell, are responsible for initial activation of naive T lymphocytes in lymph nodes during a cell-mediated immune response

dendritic

the infectious ______________ is the minimum number of a particular microbe required to cause disease

dose

fever-inducing cytokines produced by our own cells are examples of ____________ pyrogens, while microbial products that induce fever are examples of _____________ pyrogens -exogenous; endogenous -natural; artificial -endogenous; exogenous -spontaneous; induced

endogenous; exogenous

true or false: it is easier to cultivate animal viruses than bacteriophages

false; animal viruses need animals or animal cells for cultivation

binding of antibodies to ________________ interferes with a microbe's ability to move. since movement is often necessary for a pathogen to infect a host, this antibody binding can help prevent infection

flagella

unlike a B-cell receptor (BCR), a T-cell receptor (TCR) cannot bind _________ antigens -"presented" -bacterial -free -eukaryotic -viral

free

activated lymphocyte

has encountered antigen and can multiply because it has received the necessary signals to confirm that the antigen is a microbe or other harmful substance

transfer of a pathogen from your pet to you is an example of __________ transmission -vertical -horizontal

horizontal

a macrophage usually kills microbes by ____________, while a neutrophil kills by _______________. -stimulating natural killer lymphocytes; stimulating production of antibodies that can attack invading microbes -ingesting microbes and destroying them internally; releasing toxic granule components -forming granulomas; producing complement proteins that will form membrane attack complexes (MACs) -releasing toxic granule components; ingesting microbes and destroying them internally

ingesting microbes and destroying them internally; releasing toxic granule components

droplet transmission (a type of direct transmission)

large droplets that generally fall to the ground within 1 meter (3 ft) release

mucosa-associated lymphoid tissue (MALT) and skin-associated lymphoid tissue (SALT) are both examples of _________ -less-organized (diffuse) secondary lymphoid organs -lymph nodes -organs capable of producing lymph to circulate through the body -specific areas where lymphocytes for the mucosa and skin are produced

less organized (diffuse) secondary lymphoid organs

__________, which includes B cells and T cells, are the primary cell type involved in the adaptive immune responses

lymphocytes

the term ____________ is used to describe the rupture or bursting of a cell.

lysis

many health-care related infections originate from the patient's own microbial population called the normal __________

microbiota

the __________ rate reflects the overall rate of death in a given population at risk

mortality

when a B cell receptor (BCR) binds antigen, and the naive B cell is activated by confirmation from a helper T cell, the B cell then begins to __________ -form memory B cells -produce antibodies -differentiate into plasma cells -multiply

multiply

Because they are dependent on host cells, viruses are classified as ___________. -obligate intracellular parasites -facultative anaerobes -mutualistic extracellular parasites -synergistic

obligate intracellular parasites

lysogens are protected against infection by the same phage because the phage-encoded repressor protein binds to the _____________ on the incoming phage, preventing expression of the phage genes.

operator

with respect to the body's borders, the contents of the digestive tract are _____________ -outside the body -inside the body

outside the body

when memory B cells become reactivated in a secondary response, some rapidly form ____________ cells to produce antibodies. others begin ____________ to produce an additional base of cells to work with

plasma; proliferating

in a ________ epidemic, the number of ill people rises gradually -common source -propagated

propagated

in __________ transduction, only bacterial genes adjacent to the prophage can be transferred; whereas in _____________ transduction, any bacterial gene can be transferred.

specialized; generalized

factors in the physical environment that can influence the epidemiology of disease by determining which organisms can exist and reproduce include _____________ -host genetic background -oxygen level -host gender -water and nutrient supply -behavioral practices -temperature

temperature water and nutrient supply oxygen

the first-line defenses of innate immunity are ______________ -antibodies -the body's borders -complement proteins -phagocytic cells

the body's borders

before enveloped viruses bud from a host cell, specific viral proteins insert into the host membrane. these proteins become _____________. -matrix proteins -virus capsomeres -viral envelope -viral spikes

viral spikes

animals such as skunks, raccoons, and bats are reservoirs of the rabies virus. therefore, rabies is considered a(n) ___________ diesease

zoonotic