Lab Quiz 3

  1. Define mycology
    the study of fungi
  2. Define mycoses
    disease caused by funi
  3. Describe the typical appearance of a yeast cell and its usual mode of replication
    • look like beads, unicellular, oval/spherical shaped
    • reproduce by budding
  4. State two ways the yeast Saccharomyces is beneficial to humans
    used for baking & brewing
  5. Name three yeasts that commonly infect humans
    • C. albicans
    • Candida glabrata
    • Candida parapsilosis
  6. Name four common forms of candidiasis
    • thrush
    • vaginitis
    • balantitis
    • onychomycosis
    • dermatitis
  7. State the usefulness of Saboraud Dextrose agar
    • inhibits bacterial growth, promotes fungal growth
    • selective for fungi
    • good for isolating Cryptococcus
  8. State the usefulness of Mycosel agar
    • inhibits bacteria and saprophytic fungi
    • selective for pathogenic fungi
  9. State the usefulness of Rice Extract Agar
    • stimulates the formation of hyphae, blastoconidia, and chlamydoconidia
    • good for identifying Candida albicans
  10. State how Cryptococcus neoformans is transmitted to humans, where in the body it normally infects, and possible complications
    • transmitted by inhalation of yeast in dried bird feces
    • usually infects the lungs
    • can spread through the blood and to other body areas, causing cryptococcal meningoencephalitis
  11. State the primary method of identifying Cryptococcus neoformans when causing cryptococcal meningoencephalitis
    by preparing an India ink or nigrosin negative stain of suspected sputum or cerebral spinal fluid in which the yeast cells can be seen
  12. State what disease is caused by Pneumocystis jiroveci and indicate several predisposing conditions a person is normally seen to have before they contract the disease
    • Pneumocystis pneumonia (PCP)
    • usually in immunosuppressed individuals (AIDS, late-stage malignancies, leukemia)
  13. Name an infection caused by Malassezia globosa
    • tinea versicolor
    • dandruff
    • seborrheic dermatitis
  14. Define bacteriophage
    viruses that infect only bacteria
  15. Define plaque
    small, clear area on an agar plate where the host bacteria have been lysed as a result of the lytic life cycle of the infecting bacteriophages
  16. Define phage typing
    method used for identifying unknown bacteria by observing whether or not the bacteria are lysed with a known bacteriophage
  17. Describe the structure of the bacteriophage coliphage T4
    • capsid (head) surrounds nucleic acid
    • tail made of fiber
    • connected to head with a sheath
  18. Describe the lytic life cycle of bacteriophages
    • adsorption
    • penetration
    • replication
    • maturation
    • release
    • reinfection
  19. Define viral specificity
    when a specific strain of the bacteriophage will only adsorb to a specific strain of susceptible host bacterium
  20. Define hypha
    a branching, tubular structure from 2-10 ┬Ám in diameter
  21. Define mycelium
    The total mass of hyphae
  22. Define vegetative mycelium
    The portion of the mycelium that anchors the mold and absorbs nutrients
  23. Define aerial mycelium
    the portion that produces asexual reproductive spores
  24. Describe the main way molds reproduce asexually
    • by asexual reproductive spores
    • These spores are disseminated by air, water, animals or objects and upon landing on a suitable environment, germinate and produce new hyphae
  25. Deine dermatophyte and list three common genera of dermatophytes
    • a group of molds that cause superficial mycoses of the hair, skin, and nails and utilize the protein keratin as a nitrogen and energy source.
    • Microsporum
    • Trichophyton
    • Epidermophyton
  26. Name 4 dermatophytic infections and describe how they are contracted in humans
    • Dermatophytic infections are acquired by contact with fungal spores from infected humans, animals, or objects.
    • ex - tinea capitis, tinea barbae, tinea faciei, tinea corporis, tinea pedis
  27. Define dimorphic fungi and state how humans usually contract them
    • exhibit two different growth forms - Outside the body they grow as a mold but inside the body they grow as a yeast-like form
    • contracted by inhaling spores from the mold form
  28. Name three common dimorphic fungal infections found in the United States, state how they are transmitted to humans, and indicate where they are found geographically
    • Coccidioides immitis - southwestern US,
    • Histoplasma capsulatum - great lakes + mississippi + ohio river
    • Blastomyces dermatitidis - great lakes + mississippi + ohio river
    • all contracted by inhaling them somehow
  29. Describe the mold form and the yeast-like form of the following: Coccidioides immitis
    mold form grows in arid soil and produces arthrospores
  30. Describe the mold form and the yeast-like form of the following: Histoplasma capsulatum
    • mold form grows in bat or bid droppings
    • yeast form grows as encaspulated, budding form
  31. Describe the mold form and the yeast-like form of the following: Blastomyces dermatitidis
    • mold form grows in bird droppings and contaminated soil
    • yeast form has a thick cell wall
  32. State what infections are caused by Salmonella & Shigella and how they are transmitted to humans
    • salmonella - salmonellosis
    • shigella - shigellosis
    • transmitted by ingesting improperly refrigerated/uncooked/undercooked poultry, eggs, meat, dairy products, veg or fruit that is contaminated with animal feces
  33. Name four strains of E. coli that may infect the gastrointestinal tract
    • Enterotoxigenic E. coli (ETEC)
    • Enteropathogenic E. coli (EPEC)
    • Enteroaggregative E. coli (EAEC)
    • Enteroinvasice E. coli (EIEC)
    • Enterohemorrhagic E. coli (EHEC)
  34. Name five genera of Enterobacteriaceae considered as common opportunistic pathogens, their normal habitat
    • E. coli
    • Proteus
    • Enterobacter
    • Klebsiella
    • Citrobacter
    • Serratia
  35. Four common types of opportunistic infections
    • urinary tract infections
    • wound infections
    • pneumonia
    • septicemia
  36. Define nosocomial infection
    infection acquired while in the hospital
  37. Name the most common glucose-fermenting gram-negative rod that infects humans and list 5 types of opportunistic infections it may cause
    • Pseudomonas aeruginosa
    • urinary tract infections
    • would infections
    • pneumonia
    • septicemia
    • burn infections
  38. State 3 infections caused with increasing frequency by Acinetobacter
    • nosocomial wound infections
    • pneumonia
    • septicemia
  39. State the usefulness of MacConkey agar and centrimide agar for the isolation of Eneterobacteriaceae and Pseudomonas
    • macconkey - differentiates fermenting from non-fermenting bacteria
    • centrimide - selective for pseudomonas, inhibits other bacteria
  40. How do Pseudomonas and Enterobacteriaceae differ in the oxidase test
    • psuedomonas - oxidase positive
    • enterobacter - oxidase negative
  41. How do Pseudomonas and Enterobacteriaceae differ in the production of pigment & fluorescent products
    • pseudomonas - green water soluble pigment
    • enterobacter - no pigment
  42. How do Pseudomonas and Enterobacteriaceae differ in odor
    • enterobacter - foul smell
    • pseudomonas - fruity or grape-juice like aroma
Card Set
Lab Quiz 3
Labs 9-13