Practical 3 Flashcards
Define obligate intracellular parasite
Must go inside a living host organism to replicate
A virus that infects bacteria
Bacteriophage
Must go inside a living host organism to replicate
Obligate intracellular parasite
How does a medium used for bacterial growth differ from media used for bacteriophage growth?
Ordinary agar or broth media is suitable for growing bacterial cultures. Bacteria growing in lab media can serve as the host cell for growing viruses that infect bacteria.
What is the purpose of making serial dilutions of the T4 phage?
To obtain a countable plate in which 30-300 individual plaques
What is a viral plaque and what does it represent?
A plaque is an area of clearing in a confluent lawn of bacterial growth. A plaque represents the spot where a virus has landed, infected the bacteria it encountered, and lysed them.
What purpose does the E. coli serve in this procedure (Viral Plaque Assay)?
E.coli serves as the host cell for the T4 bacteriophage
The purpose of a viral plaque assay is to determine the number of bacteriophage in a sample. True or false?
True
A plaque represents where the E. coli have replicated from one cell into millions of cells
False
PFU stands for “plaque forming units”.
True
PFU
Plaque forming units
What is considered a countable # of plaques
30-300
Viruses that burst the host cell and kill them are called
Lytic viruses
Lytic viruses burst open their bacterial host cell once the appropriate number of viruses has been synthesized
True
Study of fungus
Mycology
What kind of organisms are fungi?
Eukaryotic organism
Dimorphic fungi
Grows as yeast or mold depending on the environment
What type of media is used to grow fungi?
Sabouraud’s Agar
What is speical about Sabouraud’s Agar?
Simple nutrients (gluocose and peptone)
pH of 4.5-5.6
What pH inhibits bacterial growth?
4.5-5.6
Microscopically, yeast cells are
unicellular and round to oval
Fungi that grow as mold produce
Multicellular filaments called hyphae
Asexual spores produced by molds
Sporangiospores
Conidiospores
Explain why Coccidioides immitis is a dimorphic fungus?
It can grow as a yeast or mold depending on environmental conditions
What are the growth differences between fungus and bacteria?
Fungi grow slower, at a lower temperature, and a lower pH
Define blastospore
Asexual reproductive forms of yeast that bud from parent cell
Define pseudohyphae
Successive blastospores remaining attached to the original parent cell
Successive blastospores remaining attached to the original parent cell
Pseuodohyphae
Asexual reproductive forms of yeast that bud from parent cell
Blastospore
Define septate hyphae
Fungal hyphae filaments separated by a cross wall
Fungal hyphae filaments separated by a cross wall
Define septate hyphae
Explain the difference between vegetative hyphae and aerial hyphae
Vegetative hyphae grow on or down into the agar surface to extract nutrients from the medium. Aerial hyphae grow above the agar surface
grow on or down into the agar surface to extract nutrients from the medium.
Vegetative hyphae
grow above the agar surface
Aerial hyphae
inside a sac-like structure.
Sporangiospores
are formed on hyphae and may be single or multicelled.
Conidiospores
Difference between sporangiospores and conidiospores
Sporangiospores are inside a sac-like structure. Conidiospores are formed on hyphae and may be single or multicelled.
Asexual reproductive spores are produced by ____ hyphae
Aerial hyphae
Two types of asexual spores are
Sporangiospores and Conidiospores
Saccharomyces and Candidia are ____ while
Penicillium, Rhizopus, and Aspergillus are _____
Yeast
Mold
What is the plaque equation?
Plaque count X Plate Dilution x 10 (if you plated 0.1 ml)
Staphylococcus and Micrococcus are catalase positive
True
Staphylococcus and Micrococcus are Gram (Blank)
Positive
Staphylococcus epidermidis can be an opportunist
True
Staphylococcus and Micrococcus grow in
Clusters
Streptococcus pneumoniae mostly causes
Middle ear infections
Group A Streptococcus
cause ninety percent of acute streptococcal infections in humans. It is the cause of “strep throat”
Streptococcus mutans is
another viridans streptococcus associated with dental caries and plaque.
Streptococcus can/cannot produce catalse?
Cannot (negative)