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BMS 212 mastering microbiology questions

Terms in this set (110)

An exotoxin that has the ability to kill or damage host cells is referred to as a(n)
cytotoxin
Which domain of the A-B toxin binds to cell surface receptors on the host cell?
B domain
How are superantigens different from other types of exotoxins?
Superantigens cause an overstimulation of the host immune system.
A person who attended a picnic early in the day develops a very high fever and is unresponsive by the evening. This person most likely has been exposed to a(n)
superantigen
A patient who has been hospitalized with uncontrolled muscle spasms has probably been infected with bacteria that secrete a(n)
neurotoxin
A pathogen is best described as
any microorganism that causes disease
Certain traits that allow pathogens to create infection and cause disease are termed
virulence factors
Which of the following enzymes breaks down the "glue" that holds cells together?
Hyaluronidase
Which of the following virulence factors would be found in Staphylococcus aureus?
staphylokinase
How do fibrinolysins enhance a pathogen's virulence?
They break down fibrin proteins that are involved in clot formation, allowing the cells to penetrate deep into damaged skin.
Jerica takes her young son to the pediatrician for regular childhood immunizations. While there, they wait in a room full of sneezing, sniffling, coughing youngsters. Despite making sure that her son stays at least six feet (two meters) from the other children and doesn't touch any play toys in the waiting room, microbes could still spread to her son by
vehicle transmission
An example of a mechanical vector is:
a housefly at a picnic
A patient is sickened after being infected with Escherichia coli (E. coli) from consuming contaminated lettuce; this is a type of _______________ disease transmission.
vehicle
A patient with West Nile viral encephalitis asks his nurse practitioner how he could have contracted the disease. The NP explains that the causative virus is carried by infected mosquitoes from birds to people. This is an example of disease transmission through
a biological vector
What is an endemic disease?
A disease that occurs continually within a population or geographical area
Which of the following is the CORRECT sequence of a disease process?
incubation, prodromal period, illness, decline, convalescence
A toxin common to most Gram-negative bacteria is
lipid A
Which of the following explains the role of stomach acid in the first line of defense?
It inhibits the growth of many pathogens.
The skin and the mucous membranes are similar in which of the following aspects?
Both have epithelial cells packed closely together.
How does lysozyme on the skin and in tears protect against bacterial pathogens?
Lysozyme breaks bonds in peptidoglycan in bacterial cell walls.
Which of the following statements regarding the surface of the skin is FALSE?
it has goblet cells
How does cytolysis occur via the complement pathway?
Formation of the MAC in invading cells, killing them
Which complement protein is used as an opsonin?
C3b
If a person lacked the ability to form C5, what direct result of complement could still occur?
obsonization
If a person could not form C2, which result of complement would be affected?
Cytolysis, chemotaxis, inflammation, and opsonization
What complement result involves the use of phagocytes?
chemotaxis and opsonization
What does the plasma membrane of a phagocyte attach to on a microorganism?
glycoproteins
The process by which a phagocyte moves toward a chemical signal at the site of an infection is called
chemotaxis
Which of the following phagocytic processes occurs last in the sequence?
exocytosis
What is the role of opsonins?
They create "handles" that make it easier for the pseudopods of phagocytes to attach to the microbe invader
What is a phagolysosome?
The structure that results from the fusion of a phagosome and a lysosome
If a microbe were capable of preventing a phagosome from fusing with a lysosome, which of the following would occur?
the microbe would survive inside the phagocyte
A human cell that maintains an antiviral state induced by alpha or beta interferons for too long will die because __________.
it cannot make proteins
The events of fever are antagonistic to which of the following processes?
vasodilation
The process of diapedesis is important because __________.
it allows white blood cells to leave the vessel system and attack pathogens in the tissues
What are Toll-like receptors (TLRs)?
TLRs are membrane-bound proteins that recognize structures on the surface of pathogens.
true or false: Acute inflammation is normally beneficial
true
true or false: Neutrophils can kill bacteria by nonphagocytic mechanisms.
TRUE
Which structure do antigen presenting cells utilize to directly help them present bacterial antigens?
phagolysosome
Which of the following are likely to be found on an MHC-I protein?
damaged mitochondrial fragment
What would a virally infected skin epithelial cell have on its cell surface?
Class I MHC with skin cell antigens
Which of the following would you likely see on the surface of a human dendritic cell following phagocytosis of a bacterium?
Class I MHC with dendritic cell antigens and Class II MHC with engulfed bacteria
Tom has a genetic disorder in which he does not synthesize class I MHC proteins or functional NK cells. Which of the following statements would be true for Tom?
Tom would not be able to destroy virally-infected cells.
Most often, antigens are composed of __________.
glycoproteins
Toxins and bacterial parts are considered _____ antigen because they are present outside of the body's cells.
exogenous
What is the purpose of an MHC class I protein?
MHC class I proteins display epitopes from endogenous antigen.
Which cells possess MHC class II proteins?
antigen presenting cells
In which location within the cell are epitopes bound to MHC class I proteins?
endoplasmic reticulum
Which organelle is responsible for the degradation of exogenous antigen within an antigen-presenting cell?
phagolysosome
Which of the following cells is included as an antigen-presenting cell?
macrophages
Which receptor on the helper T-cell recognizes the specific antigen from an antigen-presenting cell?
TCR
TH2 cells produce cytokines that activate
B cells
Which proteins on the antigen-presenting cell are recognized by the helper T-cell?
MHC proteins
When do helper T-cells develop into TH1 or TH2 cells?
After proliferation into a clonal population
Natural killer cells are activated by
Th1 cells
Which antibody type is largest?
IgM
A pregnant woman asks you how her unborn child can guard against "germs." You explain that she is making antibodies that cross the placenta to provide protection. What type of antibodies do this?
IgG
A laboratory scientist is checking a patient's blood type. To do this, he combines antibodies against certain blood proteins, such as protein A and protein B. If the proteins are present on the blood cells, the blood will clump. If he wants to use the most common class of antibodies, he will use
IgG
Which cells actually secrete antibodies?
plasma cells
What makes agglutination by antibodies possible?
Each antibody has at least two antigen-binding sites.
What is the role of plasma cells in humoral immunity?
plasma cells produce antibodies
Which of the following most accurately describes how a pathogenic bacterium might be affected by antibodies?
The antibodies may block proteins necessary for binding the pathogen to the host, may opsonize the bacterium, or may agglutinate bacteria.
True or false: the adaptive immune response requires exposure to specific epitopes for activation.
true
What are the targets of the two basic divisions of adaptive immunity?
B cells generally target free-floating antigen, while T cells target infected cells.
How is the development of autoimmunity normally prevented?
Clonal deletion of T cells, lack of necessary cytokine signals, and regulatory T cell suppression prevent activation of autoreactive T cells.
Breastfeeding is an example of which of the following types of immunity?
naturally acquired passive immunity
A physician wants to stimulate immunological memory in a patient. Which of the following types of immunity would be the most useful?
vaccinate with viral proteins
What is the role of helper T cells in the adaptive immune response?
Helper T cells activate B cells and cytotoxic T lymphocytes to kill infected host cells.
What is meant by the clonal expansion of a B cell?
An activated B cell divides into cells that give rise to memory B cells and plasma cells.
The student who caught the cold caused by this specific Rhinovirus was exposed to the exact same Rhinovirus 18 months later. What component of the immune system will protect her from getting the same cold again?
Memory B cells
Correctly order the steps involved cellular immunity:
1.) The Tc recognizes the infected host cell
2.) The Tc interacts with epitope presented by MHC-I on the dendritic cell
3.) The Tc secretes perforin and granzyme, causing apoptosis
4.) The helper T cell activates the Tc cell
2, 4, 1, 3
Which of the following is NOT a step used by cytotoxic T cells to kill infected host cells?
Recognition of infected host cell using its CD4 glycoprotein
Place the following steps of phagocytosis in the order that they occur:
1.) Endosome fuses with lysozome
2.) Dendritic cell engulfs Rhinovirus
3.) Epitopes are attached to MHC-II
4.) Digestion of the Rhinovirus
5.) MHC-II plus the attached epitope move to the outside of the dendritic cell
2, 1, 4, 3, 5
Which pair of molecules do NOT directly interact with one another?
BCR and TCR
Which of the following is NOT a step that ultimately leads to antibody production?
Activation of cytotoxic T cells by helper T cells
A person who has AIDS contracts rare and often life-threatening infections because their helper T cell count is so low. Which of the following components of the immune response still respond to antigen despite the low helper T cell count?
Clonal selection of B cells
Which of the following statements is true?
-Adaptive defenses include humoral immunity only.
-Innate defenses are enough to keep a person healthly.
-Memory B cells are typically established when the B cell binds to an antigen.
-Adaptive defenses include both humoral and cellular immunity.
Adaptive defenses include both humoral and cellular immunity
Vaccine manufacturers add alum, which is a common name for a variety of aluminum salts, to some vaccines. Alum enhances the ability of the vaccine to activate an adaptive immune response. Alum in such a vaccine acts as
an adjuvant
Seasonal flu nasal spray vaccines contain weakened viruses. Such vaccines are called __________ vaccines.
attenuated
Measles vaccine is to a modified live vaccine what rabies vaccine is to ______________ vaccine.
an inactivated (killed), whole agent
Shiga toxins cause human cell damage and kill patients. If some scientists are making a vaccine using deactivated Shiga toxin, what category of vaccine would it be?
toxoid vaccine
Serological tests known as ________ detect the formation of antibody-antigen complexes (immune complexes).
precipitation tests
A woman uses a home pregnancy test kit that tests for hCG hormone in urine. She knows this is a type of antibody assay from the kit brochure. Antibodies reacting with the hormone produce two lines on the test strip. What specific type of antibody assay does this represent?
an immunochromatographic assay
Tetanus toxin mixed with antibodies against the toxin and then administered to mice will result in which of the following?
There will be no effect of tetanus toxin on the mice.
true or false: For some bacterial diseases such as tetanus, it is more effective to produce an immune response against the bacterial toxin than against the bacteria.
true
The use of super-absorbent tampons has been implicated in which of the following staphylococcal diseases?
toxic shock syndrome
A strain of Staphylococcus aureus that loses the ability to produce staphylokinase will be unable to do which of the following?
spread to new locations in the body
Which of the following is an effective way to prevent many staphylococcal infections?
proper cleansing of wounds
The most significant streptococcal pathogens are found in which of the following Lancefield groups?
groups A and B
Which of the following forms of anthrax is transmitted by the endospores of Bacillus anthracis?
cutaneous, gastrointestinal, and inhalation
Which of the following species causes infections characterized by tissue death and foul-smelling gaseous waste products?
Clostridium perfringens
A mutated strain of Mycobacterium tuberculosis has lost the ability to make cord factor. Which of the following will result?
The organism will become avirulent.
A patient has a positive tuberculin skin test. Without any other information about the patient, which of the following is the most accurate interpretation of this result?
The patient has been exposed to M. tuberculosis.
Mycobacterium tuberculosis is considered a(n) __________.
aerobe
One of the primary reasons the disease is able to evade the body's immunity is that it __________.
resists digestion by phagocytes
In approximately 10% of patients tubercles rupture and reactivate infection. This is known as _____ tuberculosis.
secondary
It is estimated that _____ of the world's population may be infected with tuberculosis.
33%
How do clinicians primarily screen for tuberculosis in patients?
Tuberculin skin test
Why does tuberculosis involve months of antibiotic treatment?
The bacteria grow very slowly.
What is the name of the vaccine given to prevent TB in countries where it is endemic?
BCG vaccine
Which of the following is the best way to avoid infection by Neisseria meningitidis?
avoidance of crowded living conditions
Gonorrhea is often asymptomatic in women because __________.
the cervix is usually the site of infection
All of the following make the treatment of gonorrhea more complicated than it was in the past except __________.
an increase in cellular virulence factors
A sample from a public water supply contains Gram-negative rod-shaped bacteria that ferment lactose with gas production. Which of the following microbes would be the most likely candidate for this contaminant?
Escherichia coli
Which of the following is not an expected transmission pattern of Yersinia pestis?
humans - fleas - humans
A twenty-year-old patient exhibiting headache, stiff neck, vomiting, and convulsions has Gram-negative diplococcal bacteria in her spinal fluid. The nurse practitioner will likely diagnose infection with
Neisseria.
A patient diagnosed with bacterial meningitis likely was infected through
the respiratory route.
Protection against Neisseria or Haemophilus meningitis can be provided by
vaccines
Which of the following does not play a role in diagnosing meningitis?
sputum sample
A male patient comes into the clinic complaining of painful urination and a purulent discharge. A sample of the discharge is taken to the lab and after Gram-staining pink spheres in pairs are observed. Which of the following organisms is most likely causing the infection?
Neisseria gonorrhoeae
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