Cholera toxin is secreted by a mechanism that mimics what process
Type I pilus formation
Flagellar synthesis
Conjugation
Type IV pilus formation
Which secretion system has a needle complex for injection of bacterial toxins into the host cell?
Type I
Type II
Type III
Type IV
Which species injects a receptor for the adhesin intimin into the host cell?
Bordetella pertussis
Salmonella typhimurium
Bacillus anthracis
Vibrio cholerae
Escherichia coli
How does Shigella enter the host cell?
It binds and invade the cell by secreting proteases to digest the host cell membrane
It secretes factors that cause host cell apoptosis
It secretes factors that cause the host cell membrane to be smooth and thin, enabling invasion
It injects proteins that change the host cell cytoskeleton, causing engulfment of the bacteria
Adherence Type I: Type IV:
Match the category of exotoxin to the correct example.
❌ Staphylococcus aureus alpha toxin ❌ Vibrio cholerae RTX toxin ❌ Diphtheria toxin ❌ E. coli cytolethal distending toxin ❌ Cholera toxin ❌ Staphylococcus aureus exfoliative toxin ❌ Helicobacter pylori VacA toxin ❌ Tetanus toxin ❌ Staphylococcus auerus and Streptococcus pyogenes pyrogenic toxins
Which secretion system uses a conjugation-like machinery to secrete protein from cytoplasm or periplasm?
Which secretion system uses molecular syringe to inject proteins from bacterial cytoplasm into host cytoplasm?
What type of secretion system uses pilus-like extraction/retraction mechanism to push proteins out of the cell
, , and are all examples of structures used by microbes for adhesion.
You have recently identified a new toxin. It is produced by a gram-negative bacterium. It is composed mostly of protein, has high toxicity, and is not heat stable. You also discover that it targets liver cells. Based on these characteristics, how would you classify this toxin?
Superantigen
Endotoxin
Exotoxin
Leukocidin
You have recently identified a new toxin. It is produced by a gram-negative bacterium. It is composed mostly of polysaccharides, binds to immune cells, and triggers fevers. Based on these characteristics, how would you classify this toxin?
Adhesin
Match the toxin to its secretion system.
❌ ❌ Uses molecular syringe to inject proteins from bacterial cytoplasm into host cytoplasm ❌ ❌ Uses a conjugation-like machinery to secrete protein from cytoplasm or periplasm ❌ ❌ Uses pilus-like extraction/retraction mechanism to push proteins out of the cell ❌ ❌ Uses ABC mechanisms that move certain secreted proteins directly out of the cell
4. Which of the following pathogens does not have endotoxin?
Yersinia pestis
Vibro cholerae
If SecA were mutated, E. coli could adhere to renal cells but would be unable to secrete exotoxins to cause infection.
15. How does the plague bacterium survive the immune response?
Antigenic variance of its distinguishing surface features
Injecting exotoxins that kill macrophages
Forming spores to survive phagocytosis
Silencing pro-inflammatory cytokines
You observe a protein structure that has two subunits and is involved in bacterial pathogenesis. This protein is most likely which of the following?
Host cell receptor
Capsid protein
Pili subunit
