Topic 10 Clickers + Additional Question

Question 1

26. Which of the following statements best distinguishes normal microbiota, primary
    pathogens, and opportunistic pathogens?
    a) Normal microbiota always cause disease, while primary and opportunistic pathogens
    do not.
    b) Primary pathogens only cause disease in immunocompromised individuals, whereas
    opportunistic pathogens infect healthy individuals.
    c) Opportunistic pathogens are harmless in all situations, while normal microbiota and
    primary pathogens always cause disease.
    d) Normal microbiota typically do not cause disease under normal conditions, primary
    pathogens can cause disease in healthy hosts, and opportunistic pathogens cause
    disease mainly when host defenses are compromised.
    e) There is no meaningful difference between these groups; all microbes have equal
    potential to cause disease

Answer 1

d) Normal microbiota typically do not cause disease under normal conditions, primary
pathogens can cause disease in healthy hosts, and opportunistic pathogens cause
disease mainly when host defenses are compromised.

Question 2

27. A patient undergoing chemotherapy develops a bloodstream infection caused by
    Staphylococcus epidermidis, a bacterium commonly found on the skin of healthy
    humans. How would this microorganisms best be classified in this scenario?
    a) Normal microbiota
    b) Primary pathogen
    c) Opportunistic pathogen
    d) Obligate pathogen
    e) Mutualistic symbiont

Answer 2

c) Opportunistic pathogen

Question 3

28. Bacterial molecules that allow them to bind to host tissues are called…
    a) Attachment proteins
    b) Host recognition proteins
    c) LPS
    d) Adhesins
    e) Fimbriae

Answer 3

d) Adhesins

Question 4

29. Many bacteria adhere to host surfaces using _________, pili that are primarily used for
    attachment.
    a) Microvilli
    b) Fimbriae
    c) Pedestals
    d) Fibronectin-binding proteins

Answer 4

b) Fimbriae

Question 5

30. Virulence factors assist bacteria in…
    a) Causing disease
    b) Attaching to host cells
    c) Avoiding immune destruction
    d) All of the above
    e) None of the above

Answer 5

d) All of the above

Question 6

31. The presence of a ________ aids bacterial attachment and inhibits phagocytosis.
    a) Outer membrane
    b) Cell wall
    c) Capsule
    d) Capsid
    e) Cell envelope

Answer 6

c) Capsule

Question 7

32. One way bacterial pathogens obtain iron is by producing their own iron-binding
    molecules that can scavenge iron from the host. What are these molecules called?
    a) Cytolysins
    b) Metabolites
    c) Hemolysins
    d) Siderophores

Answer 7

d) Siderophores

Question 8

33. Which of the following correctly describes a key structural difference between
    endotoxins and exotoxins?
    a) Endotoxins are proteins, while exotoxins are lipids.
    b) Endotoxins are part of the outer membrane of bacteria, while exotoxins are proteins
    secreted by bacteria.
    c) Endotoxins are secreted only by Gram-positive bacteria, while exotoxins remain
    attached to the cell.
    d) Endotoxins are released only from living cells, while exotoxins are released when
    cells die.
    e) Endotoxins are made of DNA, while exotoxins are made of RNA

Answer 8

b) Endotoxins are part of the outer membrane of bacteria, while exotoxins are proteins
secreted by bacteria.

Question 9

34. Which of the following correctly matches a toxin type with its main mechanism of
    action?
    a) Cytotoxins – bind outside cells and overstimulate the immune system
    b) A-B toxins – have one part that binds to the cell and another part that damages the
    cell internally
    c) Superantigens – directly destroy cell membranes by forming pores
    d) Cytotoxins – enter cells and modify ribosomes to stop protein synthesis
    e) A-B toxins – only affect immune cells by causing massive cytokine release

Answer 9

b) A-B toxins – have one part that binds to the cell and another part that damages the
cell internally

Question 10

35. How does the toxin involved in a Diphtheria infection differ from other bacterial toxins?
    a) It is a protein whereas normal bacterial toxins are polysaccharides.
    b) It is a nucleic acid derivative whereas normal bacterial toxins are proteins.
    c) It is archaeal derived
    d) It is viral in origin
    e) None of the above

Answer 10

d) It is viral in origin

Question 11

36. Infection by a Gram negative bacterium can cause an immune response due to
    lipoteichoic acid, which is found in the cell membrane.
    a) True
    b) False

Answer 11

b) False

Question 12

37. Why is antigenic variation beneficial for pathogenic microorganisms?
    a) It allows microbes to grow faster in all environments
    b) It helps microbes produce more toxins
    c) It allows microbes to avoid detection by the host immune system
    d) It makes microbes resistant to antibiotics
    e) It allows microbes to survive without nutrients

Answer 12

c) It allows microbes to avoid detection by the host immune system