A reservoir is _
a source of microbial contamination.
The condition known as microbial antagonism may be defined as
an unsuccessful microbial invasion due to the presence of preexisting microbes.
An axenic environment is one
that is free of microbes.
Commensalism is best described as a(n)
relationship between two organisms where only one member benefits and the other is unharmed.
A new influenza strain appears and is spreading rapidly. What measures might be taken by public health agencies to stop the spread?
Educate the public, promote vaccination, and treat those who are infected.
Organisms that are resident microbiota are best described as
microorganisms that remain with the person throughout life.
Infectious diseases can be classified on the basis of
disease severity and duration, organ system affected or type of microbe.
Microbes known as transient microbiota are
organisms that remain in the body for a short time.
Which of the following virulence factors directly contributes to severe inflammation?
lipid A
Koch's postulates were used to demonstrate the relationship between
Haemophilus influenzae and meningitis.
The person known to history as "Typhoid Mary" never had typhoid fever but was identified by public health officials as a source of Salmonella enterica Typhi. Which of the following is the most accurate description of her in this scenario?
both a human carrier and a reservoir
A strain of Neisseria gonorrhea has a mutation which has caused it to lose the ability to produce fimbriae and become less virulent as a consequence. What function has this pathogen lost?
the ability to adhere to cells of the body
A person is exposed to rotten wood with fungal growth and develops blastomycosis. No one taking care of him/her becomes ill. Blastomycosis is an example of a ________ disease.
noncommunicable
Sebum contains ________ which contributes to creating an inhospitable environment on the surface of the body.
acids
TLRs are
phagocyte receptors that detect PAMPs.
Microbial molecules detected by phagocytes are called
PAMPs.
A type of lymphocyte called a(n) ________ detects cells with abnormal surface proteins and kills them.
NK cell
The alternative pathway of complement cascade activation begins with ________ binding to the surface of a microbe.
c3b
What are NOD proteins?
cytoplasmic receptors of microbial molecules
Which of the following statements regarding phagocyte recognition of pathogens is true?
TLRs in the phagocyte cytoplasmic membrane bind surface structures of microbes.
Opsonization is
the coating of a pathogen by complement to facilitate phagocytosis.
The phenomenon known as chemotaxis is defined as
the movement of a cell toward or away from a chemical stimulus
Alpha and beta interferons
are produced by infected fibroblasts and macrophages.
Which of the following is an iron-binding protein produced by pathogens to access the body's store of iron?
siderophores
Mucous membranes are quite thin and fragile. How can such delicate tissue provide defense against microbial invaders?
the mucus physically traps microbes, contains a variety of antimicrobial chemicals, and is shed constantly, along with the outermost layer of cells.
Which of the following is the result when a CTL interacts with a virally infected cell?
The cell undergoes apoptosis.
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.
IgE antibodies are best described as
a cause of basophil and eosinophil degranulation.
What is the result when a dendritic cell phagocytizes a microbe and processes it?
display of microbial epitope-MHC II complexes on the cell surface
The immunological synapse refers to the
interaction between a T cell and an antigen-presenting cell to produce a specialized cell-to-cell contact area.
The protozoan that causes malaria is an intracellular parasite of red blood cells (RBCs). An adaptive immune response to this parasite is problematic because
red blood cells do not produce MHC and, therefore, do not display the fact that they have been infected by presenting antigen.
Which of the following statements regarding antibody function is FALSE?
They can penetrate host cells to bind intracellular antigens.
Which of the following statements about lymphocytes is FALSE?
B and T lymphocytes can be differentiated using a bright-field light microscope.
Infection with influenzavirus is commonly diagnosed using
both immunochromatographic assay and viral hemagglutination inhibition test.
Serologic tests may be used to detect ________ for diagnosis of disease.
antigen-specific antibodies
A new virus is discovered that causes cells to lyse. Which of the following types of assay would be useful for diagnosing infection with this virus?
viral neutralization
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
The complement fixation test uses red blood cells as the target for complement activation. Test serum containing antibodies is combined with a known amount of antigen in a tube, and then the RBCs and antibodies against the RBCs are added. A positive result for the complement fixation test would be
a cloudy solution in the tube.
Tuberculosis may be diagnosed using a(n) ________ on sputum (lung fluid) samples.
direct fluorescent antibody test
a person who has been exposed to rabies receives both HRIG (human rabies immunoglobulin) injected near the bite site and the rabies vaccine. What does this strategy represent?
active immunization combined with passive immunotherapy
What type of vaccine is the hepatitis B vaccine?
a recombinant vaccine composed of a single antigen of the hepatitis virus
Systemic lupus erythematosus (SLE or lupus) is distinct from other autoimmune disorders because
multiple organs and tissues are affected.
The syndrome known as AIDS is characterized
by one or more opportunistic diseases and the presence of HIV.
Antigen-antibody complexes trapped in tissues and triggering complement activation or mast cell degranulation are characteristic of
autoimmunity.
Treatment with glucocorticoids to suppress type IV hypersensitivity may result in
acquired immunodeficiency.
A child has a history of recurring serious bacterial infections. A blood sample shows lymphocyte levels are a little below normal, and no antibodies to the pathogens are detected in serologic tests. Based on this information, which of the following is the likeliest diagnosis for this child?
Bruton-type agammaglobulinemia
Which of the following statements concerning rheumatoid arthritis (RA) is TRUE?
Accumulations of antibody complexes lead to inflammation in and destruction of the joints.
Hypotheses explaining the development of autoimmune disease include
molecular mimicry and genetic factors
A small amount of antigen is injected under the skin of a patient. After 30 minutes there is no apparent change at the injection site, but 36 hours later the patient reports that the area is red and swollen. This type of response is due to
type IV hypersensitivity.
Parasitic worms, even meters-long tapeworms, are studied in microbiology because
diagnosis usually involves microscopic examination of patient samples.
A reaction requires water as a reactant and produces heat. What type of reaction is likely to be involved?
a synthesis reaction
Which of the following is an accurate description of ATP?
ATP serves as a recyclable energy for cells.
Lipid A is a component of
the outer membrane of Gram-negative bacteria.
ATP is expended in which of the following processes?
both active transport and group translocation
Which of the following statements concerning endocytosis is TRUE?
Endocytosis produces a structure called a food vesicle.
An important function of nomenclature is to
facilitate unambiguous communication.
The Apicomplexa are named for their apical complexes which allow them to
penetrate the cytoplasmic membranes of host cells.
The process in which the cytoplasm is divided between daughter cells is known as
cytokinesis.
Why is lysogeny advantageous to a bacteriophage?
the genetic material of the bacteriophage is amplified many times over that seen in a lytic phage.
Substrate-level phosphorylation occurs during which of the following stage(s) of glucose catabolism?
energy-conservation stage of glycolysis
The metabolic processes called fermentation
use an organic molecule as a final electron acceptor.
Nitrogen is a growth-limiting nutrient for many organisms because
only a few microbes can extract it from the atmosphere, but all organisms require it for amino acid and nucleotide synthesis.
Obligate anaerobes may be cultured in the laboratory
in a reducing medium.
An epidemiologist is investigating a new disease and observes what appear to be bacteria inside tissue cells in clinical samples from victims. The scientist wants to try to isolate the bacteria in the lab. What culture conditions are most likely to be successful?
inoculation of cell cultures
DNA is composed of four nucleotides, A, C, G and T. Each codon is composed of three nucleotides. The number of possible codons is
64
Amino acids are delivered in their appropriate order by
tRNAs
The natural role of restriction enzymes in bacteria is to
protect the cell from invading phages.
What is the function of the high temperature step in PCR (polymerase chain reaction)?
break hydrogen bonds for strand separation
The enzyme reverse transcriptase
synthesizes DNA from an RNA template.
Which of the following is an example of pasteurization?
synthesizes DNA from an RNA template.
You notice a sign in a public restroom that states "Sanitized for your safety." This means
methods of disinfection that meet minimum standards of microbial removal have been used.
The process of filtration is a(n)
sterilizing method.
The mechanism of action of ciprofloxacin is
inhibition of nucleic acid synthesis.
How does resistance to drugs spread in bacterial populations?
Horizontal gene transfer between bacteria spreads R (resistance) plasmids.
The therapeutic range of an antimicrobial is the
range of concentrations at which the antimicrobial is both effective and non-toxic.
Which of the following statements concerning transcription in bacteria is FALSE?
Different RNA polymerases are required for synthesis of mRNA, rRNA, and tRNA.
The production of NADH takes place during the ________ stage(s) of glycolysis.
energy-conservation