Lecture 1 - intro to microbiology Flashcards
list the categories of microorganisms
- bacteria
- archaeans
- protozoa
- molds and yeasts
- viruses
what is microbiology?
the study of very small living organisms
what is an extremophile?
a microorganism that can live under extreme conditions
what is a halophile?
need high salt concentrations
what is a thermophile?
can survive at temperatures between 60-120 degrees
what is a cryophile?
grows better at temperatures of 15 degrees or lower
what is an acidophile?
has an optimum pH level at or below 3
what is an alkaliphile?
has optimum growth pH levels of 9 or above
what is a xerophile?
grows in extremely dry or desiccating conditions
what is the average size of a bacterium?
approximately 10um
what is a brightfield microscope used for?
most common, gram staining
what is a darkfield microscope used for?
examination of very thin organisms against a dark background
what is the magnification of a brightfield microscope limited to?
1000x due to the light that is used.
what is a phase contrast microscope use for?
observing unstained live organisms
what is a fluorescence microscope used for?
mainly for immunodiagnostic fluorescent dye attached to an organism
what is a scanning electron microscope used for?
examination of surface features of cells and viruses, gives illusion of depth
what is a transmission electron microscope used for?
examination of cellular and viral ultra-structure, reveals internal features
what is the most powerful microscope?
High-resolution transmission electron microscopy
what are the taxonomic categories?
- life
- domain
- kingdom
- phylum
- class
- order
- family
- genus
- species
what is a strain?
genetic variant of the same species (subtype)
what is a serotype?
subtype that can be defined by using specific antibodies
what is a pathovar?
subtype with tissue/host specificity
what is an isolate?
pure microbial sample obtained from an infected individual (or no variation)
what are the two ways to culture bacteria and yeasts?
agar plate and a liquid culture (broth)
what is the process of bacterial growth called at the individual level?
binary fission
obligate aerobes:
require O2 and there is no fermentation
obligate anaerobes:
cannot survive in presence of O2
facultative anaerobes:
can metabolise energy aerobically (respiration) or anaerobically (fermentation)
microaerophiles:
require O2 but cannot survive in higher concentrations of O2
aerotolerant bacteria:
cannot utilize O2 (fermentation only) but are not harmed by O2
how can we test for O2 dependency in bacteria?
grow it in thioglycolate broth
what are the main bacterial morphology we will be examining?
shape: coccus and bacillus
Cell wall: gram +ve and -ve
what are the features of gram +ve bacteria?
Have one cell wall with an exterior thick protective peptidoglycan capsule
what are the features of a gram -ve bacteria?
have both an inner and an outer membrane, with only a thin peptidoglycan layer between the two
what powers a flagella?
proton motive force
what are fimbriae/pili?
used for attachment to host cells/other bacteria
what is used to transfer genetic material in horizontal gene transfer?
sex pili, which attach to the other bacterium and transfer a single strand of DNA from the plasmid to another bacterium
what is a slime layer?
- not highly organised
- loosely attached
- used for gliding, aggregation
what is a capsule?
- highly organised
- firmly attached
- chemical composition varies
- protects bacteria from drying out and the immune system.
what is an endospore?
a survival mechanism for bacteria.
- can survive very harsh conditions for many years but cannot reproduce
what is a protozoa?
a single cell eukaryote
what is a metazoa?
multicellular organisms
true or false, prokaryotes contain mitochondria, ER and golgi
false
where does respiration occur in prokaryotes?
cytoplasmic membrane
what environmental conditions is likely to be the most inhibiting factor that microbes encounter on an inanimate object?
water availability
Escherichia coli is a Gram-negative bacterium. In taxonomy the term Escherichia refers to the?
genus
