Homework 5 Flashcards
Organs have varied mechanisms for limiting the amount and types of colonizing microbiota. In the choices below, organs are matched with one of their microbiota-limiting mechanisms. Which organ and mechanism are mismatched?
A. bladder – presence of bile salts
B. intestine – secretion of lectins that separate the microbiome from the host mucosal cells
C. lungs – action of the mucociliary escalator
D. eye – constant washing action with antimicrobial factors such as lysozyme
E. skin – presence of dry, high-salt environments
A. bladder – presence of bile salts
Where would you find Lactobacillus crispatus?
vagina
Where would you find Bifidobacterium, Clostridium, E.coli, and methanogens?
intestines
Where would you find Staphylococcus epidermis, Bacillus, and Propionibacterium?
skin
Where would you find Streptococcus mutans, Streptococcus salivarius, Staphylococcus aureus, and Staphylococcus epidermis?
oral and nasal cavities
Michael has Acquired Immunodeficiency Syndrome (AIDS) caused by the Human Immunodeficiency Virus (HIV). The damage that the virus has done to Michael’s immune system has made him susceptible to a yeast infection of his respiratory tract, called Candidiasis. Individuals with a healthy immune system do not develop this yeast infection.
Michael is a(n)
________ and the yeast that causes Candidiasis is a(n)
__________
compromised host
opportunistic pathogen
What are some concepts of innate immunity?
involves physical barriers
is nonspecific
includes the alternative complement pathway
is triggered by peptidoglycan and lipopolysaccharide
What are some concepts of adaptive immunity?
involves specific antigens
involves memory cells
produces antibodies
reacts more slowly during initial infection
Macrophages ingest and degrade microbes and present the microbial antigens to other immune system cells.
Antibodies on the surface of virally infected host cells activate natural killer (NK) cells.
These two statements are examples of the connections between which of the following?
A. innate and adaptive branches of immunity
B. phagocytosis and inflammation
C. neutrophil extracellular traps (NETs) and the disease lupus
D. primary and secondary lymphoid tissues
A. innate and adaptive branches of immunity
Swelling and altered function at an affected site represent two of the five major signs of inflammation in the body. What are the others?
Choose one or more:
A. fever
B. pus
C. redness
D. pain
E. heat
C. redness
D. pain
E. heat
HERPA (heat, edema (swelling), redness, pain, and altered function)
Which of the following locations is LEAST likely to harbor commensal microbes?
A. Skin
B. Mouth
C. Vagina
D. Blood
D. Blood
Microbes that colonize the skin need to be resistant to __________ salt and __________ pH.
A. low; high
B. low; low
C. high; low
D. high; high
C. high; low
Microbial species of the microbiota may interfere with colonization of pathogens by all EXCEPT which of the following mechanisms?
A. Phagocytosis
B. Competition for food sources
C. Competition for attachment receptors on host cells
D. Through the synthesis of antimicrobial compounds
A. Phagocytosis
Innate immunity is also called __________ immunity.
A. antibody-mediated
B. nonadaptive
C. adaptive
D. antigen-mediated
B. nonadaptive
Which of the following is true of macrophages?
A. They are unable to perform phagocytosis.
B. They produce antibodies in response to antigens presented by antigen-presenting cells.
C. They are the cells most likely to first encounter an invading pathogen.
D. They participate in the innate immune response but not in the adaptive immune response.
C. They are the cells most likely to first encounter an invading pathogen.
Which of the following chemical defenses are produced by host cells to destroy invaders’ membranes?
A. Lysozyme
B. Superoxides
C. Defensins
D. Acidic pH
C. Defensins
Which of the following is true of the adaptive immune response?
A. B cells mostly mediate cellular immunity and T cells mostly mediate humoral immunity.
B. A clonal population of plasma cells can produce antibodies to many different epitopes.
C. T cells can directly kill infected host cells but B cells cannot directly kill cells.
D. T cells can differentiate into antibody-secreting plasma cells.
C. T cells can directly kill infected host cells but B cells cannot directly kill cells.
The first cells likely to encounter a pathogen, such as phagocytes, are professional antigen presenting cells (APCs). This means they
A. can produce antibodies against the pathogen.
B. can activate cells of the adaptive immune system.
C. are primed to proliferate and attack the invader.
D. can activate complement.
B. can activate cells of the adaptive immune system.
The primary antibody response differs from the secondary antibody response in that
A. antibodies appear in the serum sooner during the primary response.
B. in the primary response, plasma cells differentiate from naive B cells, whereas in the secondary response, plasma cells may differentiate from memory B cells.
C. antibodies present during the primary response have a higher affinity for antigens than antibodies present during the secondary response.
D. only the secondary antibody response is triggered by an encounter with an antigen; the primary antibody response occurs spontaneously.
B. in the primary response, plasma cells differentiate from naive B cells, whereas in the secondary response, plasma cells may differentiate from memory B cells.
Which cell surface protein is expressed in all nucleated cells?
A. CD4
B. CD8
C. MHC II
D. MHC I
D. MHC I
Herd immunity reduces risk for all but which of the following kinds of disease?
A. Sexually transmitted diseases
B. Diseases that do not require person to person contact
C. Diseases spread by indirect transmission
D. Diseases spread accidentally
B. Diseases that do not require person to person contact
What are the steps of antibody production from start to finish?
Gene rearrangements determine the antibody specificity of any given B cell
Naive B cells leave the bone marrow
B cells encounter a foreign antigen with specificity for their particular antibody
Activated B cells differentiate into plasma cells
Antibodies specific to a foreign antigen are produced and secreted
What are the steps of the immune response when vaccines are given?
Primary vaccination/infection
Primary response
Secondary vaccination/booster/reinfection
Secondary response
Which of the following describes why the secondary immune response is much quicker and greater than the primary response to the same antigen?
A. T cells are involved in the secondary immune response but not during the primary response.
B. Memory B cells are in place when the same antigen is encountered again.
C. Naive B cells are in excess and poised for a quick, strong secondary response.
D. During the primary immune response, the antigen is quickly covered by antibody, slowing the response.
B. Memory B cells are in place when the same antigen is encountered again.
A child was exposed to a disease-causing virus (most likely chicken pox from the Varicella zoster virus) when he was 5 years old. At 12 years old, the child encounters the same virus again. What is most likely expected to happen?
A. The child will be administered antibiotics immediately to remove the disease-causing pathogen.
B. The pathogen will be neutralized with antibody quickly and the virus will be cleared before symptoms develop.
C. Since macrophages already acted against the pathogen, they will engulf the virus immediately upon exposure.
D. After a short lag phase, the child will mount an immune response and serum antibody concentration will increase.
B. The pathogen will be neutralized with antibody quickly and the virus will be cleared before symptoms develop.
What are the different regions of an antibody?
One non-variable region
Two variable regions
Which of the following best describes antibody structure and function?
A. Each antibody has one variable region that is specific to only one antigen.
B. Each antibody has one variable region that is specific to multiple antigens.
C. Each antibody has two variable regions that are each specific to different antigens.
D. Each antibody has two variable regions that are both specific to the same antigen.
D. Each antibody has two variable regions that are both specific to the same antigen.
Where are heavily chained amino acids expected to be found in an antibody?
The longitudinal structure of the antibody, or the non-variable section
What else is an antibody called? Where is it located?
B-cell receptor
B cell
What cell links and activates a B cell that is bound to an antigen?
T cell
Within the immune cell interaction shown in Part 1, which of the following types of immunity are shown?
A. innate
B. adaptive
C. humoral
D. cell-mediated
B. adaptive
C. humoral
D. cell-mediated
If a patient has been diagnosed with human immunodeficiency virus (HIV), then part of their
_________ immunity is not functioning properly.
Which cell does this typically cause to malfunction?
innate AND adaptive
T cell
Which type of secretion involves a piston-like shaft that can polymerize/depolymerize to push toxins through a channel in the outer membrane?
type-II
What is direct transmission?
person to person through direct contact
What is vertical transmission?
infection spread from mother to developing offspring
direct
What is vector transmission?
parasites, such as ticks, pass disease to host
indirect
What is vehicle transmission?
spread through fomites, food, water, and/or air
indirect
What does LD50 measure?
how much bacteria or virus is needed to kill 50% of hosts if microbe can cause death
What does ID50 measure?
how much bacteria or virus is needed to cause symptoms in 50% of hosts if microbe is nonlethal
Virulence is measured by __________, or the dose needed to __________ of hosts.
A. LD50; infect 50%
B. ID50; cause symptoms in 50%
C. ID100; colonize 100%
D. LD100; kill 100%
B. ID50; cause symptoms in 50%
Foodborne pathogens likely use __________ as a portal of entry.
A. the parenteral route
B. inhalation
C. the mouth
D. a wound
C. the mouth
Which of the following is an example of vertical transmission?
A. Insects pass the yellow fever virus to humans upon biting them.
B. Children get ill from food prepared by their mother.
C. Insects pass the yellow fever virus to their offspring in their eggs.
D. A child catches a cold because her mother sneezed and coughed on her.
C. Insects pass the yellow fever virus to their offspring in their eggs.
Suppose a suspected virulence gene is deleted from a pathogenic organism. If the gene product did indeed decrease virulence, the modified organism will have
A. a higher LD50 than the unmodified, gene-containing organism.
B. increased infectivity compared with the unmodified, gene-containing organism.
C. a slower growth rate in culture media compared with the unmodified, gene-containing organism.
D. a greater range of host organisms it can infect.
A. a higher LD50 than the unmodified, gene-containing organism.
The ability of HIV to use a capsular protein to bind to the host cell CCR5 receptor is an example of which type of virulence factor?
A. Nonpilus adhesins
B. Biofilm production
C. Bacterial pili
D. AB exotoxin
A. Nonpilus adhesins
Which of the following is NOT an exotoxin?
A. LPS
B. Hemolytic alpha toxin
C. Shiga toxin
D. RTX toxin that depolymerizes actin of the cytoskeleton
A. LPS
A human obligate intracellular parasite can grow in phagolysosomes. From this information we can assume that this organism can grow in
A. temperatures greater than 42°C.
B. environments extremely high in sodium chloride.
C. alkaline conditions.
D. acidic conditions.
D. acidic conditions.
Extracellular pathogens can attempt to avoid immune detection by
A. altering their cell-surface proteins.
B. growing within a phagolysosome.
C. tolerating acidic conditions.
D. inhibiting phagosome-lysosome fusion.
A. altering their cell-surface proteins.
An obligate intracellular pathogen like Rickettsia compares to a facultative one like Salmonella in that it
A. cannot grow outside the host cell.
B. can escape the phagosome more readily than the facultative one.
C. is not as well adapted to survive within the host cell.
D. is an acidophile.
A. cannot grow outside the host cell.
A pathogenic bacterium has a low lethal dose 50% (LD50). Which of the following statements about the bacteria is true?
A. The bacteria have a high infectious dose 50% (ID50).
B. Only a few of the bacteria are required to kill 50% of infected hosts.
C. A small dose of an antibiotic drug is sufficient to kill the bacteria.
D. The bacteria have a low virulence.
B. Only a few of the bacteria are required to kill 50% of infected hosts.
Mycobacterium tuberculosis infects the lungs and can spread to other organs from the lungs. When an infected individual coughs, the bacteria can enter the air and infect nearby individuals.
The mode of transmission for the M. tuberculosis pathogen is the ________ route.
The portal of entry for M. tuberculosis is _______.
direct airborne
respiratory
Typhoid Mary was a professional cook at the turn of the twentieth century who was an asymptomatic carrier of the bacteria Salmonella Typhi. She infected many people who ate at the eating establishments where she worked through contaminated food.
The mode of transmission for the S. Typhi pathogen is the _________ route.
The portal of entry for S. Typhi is ________.
indirect vehicle
oral
Lyme disease is caused by the bacteria Borrelia burgdorferi, which is transmitted through the bite of a tick.
The mode of transmission for the B. burgdorferi pathogen is the ________ route.
The portal of entry for B. burgdorferi is ________.
indirect vector
parenteral
Which of the following are examples of virulence factors?
A. hemagglutinin envelope protein on the surface of the influenza virus that binds to a receptor on the surface of host cells
B. capsule of Neisseria meningitidis that prevents phagocytes from adhering to the bacteria
C. botulinum toxin produced by Clostridium botulinum that blocks host nerve transmission
D. Rubisco enzyme that fixes carbon dioxide in cyanobacteria
E. DNA polymerase of Mycobacterium tuberculosis that replicates the bacterial DNA
F. Rab1b protein in Yersinia pestis that prevents the fusion of lysosomes and phagosomes in host macrophages
A. hemagglutinin envelope protein on the surface of the influenza virus that binds to a receptor on the surface of host cells
B. capsule of Neisseria meningitidis that prevents phagocytes from adhering to the bacteria
C. botulinum toxin produced by Clostridium botulinum that blocks host nerve transmission
F. Rab1b protein in Yersinia pestis that prevents the fusion of lysosomes and phagosomes in host macrophages
Which of the following statements about virulence factors is true?
A. They are found in nonpathogenic strains of a microbe as well as pathogenic strains.
B. They are defined as being any genes that are required for microbial survival.
C. They always activate host defenses.
D. They increase the ability of a pathogen to cause disease.
D. They increase the ability of a pathogen to cause disease.
A gene coding for __________ proteins is likely to be found in a genomic island of a pathogenic bacterial strain and NOT found in a nonpathogenic strain.
A. glucose transporter
B. tRNA amino acyl synthase
C. RNA polymerase
D. host cell attachment
D. host cell attachment
The pathogenic strain of Escherichia coli, E. coli O104:H4, expresses the Shiga toxin and is highly resistant to many antibiotics. How did the E. coli O104:H4 strain originally obtain the genes for the Shiga toxin and antibiotic resistance?
A. random mutation
B. horizontal gene transfer
C. immunopathogenesis
D. vertical transmission
B. horizontal gene transfer
The E. coli O104:H4 outbreak of 2011 was caused by a strain that had Shiga toxin and antibiotic resistance traits not present in its closest relative. This most likely indicates
A. there was a horizontal gene transfer event.
B. the strain evolved through genome duplication and divergence.
C. there was a multiple mutation event increasing the virulence of this strain.
D. this is a completely new strain of Shigella that appears more like E. coli.
A. there was a horizontal gene transfer event.
What are some factors of endotoxins?
released by dead cells
harm the host by overstimulating the host’s immune defense
component of lipopolysaccharide
What are some factors of exotoxins?
secreted by living cells
composed of protein
include hemolysins
produced by gram-positive bacteria
What are some factors of both endotoxins and exotoxins?
are virulence factors
produced by gram-negative bacteria
The Streptococcus pneumoniae bacteria
A. is the only causative agent of pneumonia.
B. is unlikely to infect immunocompromised patients.
C. can only cause lung infections.
D. is surrounded by a polysaccharide capsule that makes phagocytosis very difficult.
D. is surrounded by a polysaccharide capsule that makes phagocytosis very difficult.
Diarrhea and vomiting are symptoms associated with __________ infections.
A. chlamydia
B. uropathogenic E. coli
C. rotavirus
D. rhinovirus
C. rotavirus
Symptoms of food poisoning differ from food infection in that while both present with diarrhea,
A. food poisoning is accompanied by bleeding in the stool.
B. symptoms of food poisoning occur within 2–6 hours of ingestion, and those of food infection take 12–24 hours to appear.
C. food poisoning symptoms will be resolved with antibiotics.
D. the symptoms of food poisoning last considerably longer than those of food infection.
B. symptoms of food poisoning occur within 2–6 hours of ingestion, and those of food infection take 12–24 hours to appear.
Helicobacter pylori infection may lead to
A. urinary tract infection.
B. upper respiratory infection.
C. tuberculosis.
D. ulcers.
D. ulcers.
The most common way that bacteria are introduced to the urinary tract system is from bacteria in the
A. bladder ascending into the kidney.
B. kidney descending into the bladder.
C. urethra ascending into the bladder.
D. bloodstream depositing into the kidney.
C. urethra ascending into the bladder.
Which of the following is the most common cause of UTIs?
A. Chlamydia spp.
B. Escherichia coli
C. Staphylococcus spp.
D. Klebsiella spp.
B. Escherichia coli
What makes uropathogenic E. coli different from other strains?
A. Ability to invade via catheter
B. A P-type pilus allowing binding to cells lining the urinary tract
C. There are no detectable differences between this and other strains.
D. Resistance to acidic conditions
B. A P-type pilus allowing binding to cells lining the urinary tract
Which of the following organisms is sexually transmitted?
A. Streptococcus pneumoniae
B. Neisseria menigitides
C. Neisseria gonorrhoeae
D. Giardia lamblia
C. Neisseria gonorrhoeae
The __________ plague is easily transmitted from person to person.
A. bubonic
B. septicemic
C. pneumonic
D. cardiac
C. pneumonic
A bulls-eye rash is an indicator of what bacteria?
A. Borrelia burgdorferi.
B. Chlamydia trachomatis.
C. Streptococcus pneumonia.
D. Treponema pallidum.
A. Borrelia burgdorferi.
The blood-brain barrier
A. is the meninges surrounding the brain.
B. occurs via capillary leakiness in the central nervous system.
C. helps prevent infection of the central nervous system.
D. aids in delivering drugs to the central nervous system.
C. helps prevent infection of the central nervous system.
Meningitis is
A. inflammation of the sensory organs of the head, including the eyes, ears, nasal passages, and tongue.
B. inflammation of the membranes surrounding the brain and spinal cord.
C. inflammation of the brain.
D. demyelination of the nerves of the spinal cord.
B. inflammation of the membranes surrounding the brain and spinal cord.
Staphylococcal exfoliative toxin is responsible for the characteristic signs of
A. scalded skin syndrome.
B. necrotizing fasciitis.
C. cellulitis.
D. impetigo.
E. folliculitis.
A. scalded skin syndrome.
What are the steps of phagocytosis from first to last?
Phagocyte pseudopod clasp and engulf the microbe
The microbe is trapped within a phagosome
A lysosome fuses with the phagosome, forming a phagolysosome
Enzymes cleave the macromolecules and generate reactive oxygen species, destroying the microbe
The microbial debris is released from the cell
Which of the following statements about macrophages is false?
A. Macrophages are involved only in innate immunity.
B. Macrophages are phagocytic.
C. Macrophages differentiate only from monocytes.
D. Macrophages present microbial peptide antigens on major histocompatibility complexes.
A. Macrophages are involved only in innate immunity.
