39 Questions
What are the subunits that comprise 70S ribosomes?
50S and 30S
Which taxonomic rank is commonly used and usually just the genus and species?
Genus
What is used to determine the closeness of relationship between various bacteria at the molecular level?
DNA hybridization
Which shape is not among the cell shapes that occur among unicellular true bacteria?
Cuboidal
What is a frequent drug target in bacteria?
Antibiotic sensitivity or resistance
How do bacterial toxins inhibit host cells?
By forming pores in host cell membranes
What is the clinical feature associated with Vibrio cholerae infection?
Watery diarrhea
Which pathogen causes the disease characterized by severe watery diarrhea?
Vibrio cholerae
What is the primary treatment for Vibrio cholerae infection?
Oral rehydration
What is the motility characteristic of Vibrio cholerae?
Motile
What is the primary purpose of evading host defenses for pathogenic microorganisms?
To complete the full cycle in the host
Which bacterial species exhibits specificity (tropism) for tooth surfaces?
Streptococcus mutans
What determines the tissue specificity (tropism) of bacterial attachment to host cells?
Adhesin-receptor interaction
Which portal of entry is commonly associated with pathogenic microorganisms transmitted by insect vectors?
Direct inoculation
What is the main purpose of shedding from the body for pathogenic microorganisms?
To ensure spread to fresh hosts
What is the main function of bacterial capsules?
Prevent phagocytosis by phagocytic cells
What is the composition of the capsule of Bacillus anthracis?
Polymer D-glutamate
Why do bacteria form biofilms?
To prevent desiccation
What is the effect of molecular mimicry as an immune evasion strategy?
Prevent complement and antibody deposition
How do changes in DNA sequence lead to antigenic variation?
By modifying the pilin protein of bacteria
What is the term for directional motility mediated by the flagellum?
Chemotaxis
Which bacterial motility occurs via retraction and extension of the pilus?
Twitching motility
Which bacteria are examples of those that exhibit flagella-independent motility?
Neisseria gonorrhoeae
What is the term for localized production of enzymes such as toxins, proteases, and DNases by bacteria?
Toxin production
What is the term for the form of solid surface translocation exhibited by bacteria?
Twitching motility
What is the mechanism of antigenic variation for N.gonorrhoeae pilin?
Homologous recombination between pilE and pilS loci
What is the function of the variable region pilS in N.gonorrhoeae?
Homologous recombination with pilE
Which immune evasion strategy is utilized by many bacteria to avoid detection?
Stealth - capsules, biofilms
What is the role of molecular mimicry in bacteria?
Trigger autoimmune disorders
Which molecule is commonly found on the surface of Neisseria and Haemophilus, contributing to their molecular mimicry?
Sialic acid
What is the size range of bacteria?
0.1–10 μm
Which of the following is true about the genetic organization of bacteria?
Double stranded DNA organized into a circular chromosome
What is the function of plasmids in bacteria?
Small DNA molecule that is separate from chromosomal DNA
Which component is most commonly found in the cell wall of bacteria?
Peptidoglycan
What is the typical morphology of E.coli?
Rod-shaped
Which of the following is a characteristic of prokaryotic organisms?
No defined nucleus
What is the primary genetic material in bacteria?
DNA
In bacterial cells, what is the structure where the DNA is located?
Nucleoid
What is the size range of E.coli?
~1µm diameter, 2µm length
Test your knowledge of immune evasion strategies employed by pathogens. Learn about how pathogens use tactics such as hiding in capsules, forming biofilms, antigenic variation, and molecular mimicry to evade the host immune system.
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