Microbiology Flashcards
(666 cards)
what are examples of bacteria and viruses, from largest (30μm) to smallest (less than 1μm)
trypanosoma gambiense entamoeba histolytica borrellia recurrentis treponema pallidum bacillus anthracis escherichia coli staphylococcus aureus rotavirus chlamydia trachomatis vaccinia virus influenza virus wart virus poliovirus
what is bacterial nomenclature? what is an example?
staphylococcus (genus) aureus (species)
what is a pathogen?
organism that causes or is capable of causing disease
what is a commensal?
organism which colonises the host but causes no disease in normal circumstances
what is an opportunist pathogen?
microbe that only causes disease if host defences are compromised
what is virulence/pathogenicity?
the degree to which a given organism is pathogenic
what is asymptomatic carriage?
when a pathogen is carried harmlessly at a tissue site where it causes no disease
what is the diameter of the smallest body that can be resolved and seen clearly with the naked eye?
100μm
what are colonies?
bacteria and fungi form macroscopically visible structures comprising at least 10^8 cells (when propagated on solid media)
what are the three domains of life?
bacteria, archaea and eukarya
what is the anatomy of a bacterial cell?
- cytoplasm bound peripherally by a very thin, elastic and semi-permeable cytoplasmic/plasma membrane (phospholipid bilayer)
- the cell wall is outside and closely covering the membrane, which is porous and permeable
- cell division mediated by actin-like protein, FtsZ
- septum/cross wall
- S-layer is a variably demonstrated ordered protein layer
- capsule
- fimbriae
- flagellum
- sex pili
what combines to produce the cell morphology and characteristic patterns of arrangement?
the exact pattern of cell division and the structures associated with the cell wall and cytoplasmic membrane (collectively the cell envelope)
what are the two basic shapes of bacterial cells?
coccus: spherical
bacillus: rod shaped
what shape are bacterial cocci?
spherical
what shape are bacterial bacilli?
rod shaped
what are variations of bacilli?
vibrio: comma shaped
spirillum and spirochaete: spiral
filamentous
what are the shapes and characteristic groupings of various bacterial cells?
- diplococci
- streptococci
- staphylococci
- sarcina
- bacillus
- vibrio
- spirillum
- actinomyces
what are the structures in bacteria cytoplasm that correspond to eukaryotic actin, tubulin and intermediate filaments?
MreB, FtsZ and crescentin respectively
what types of larger structures occur in some species of bacteria under specific growth conditions?
spores or inclusion bodies of storage products e.g. volutin (polyphosphate), lipid (poly-beta-hydroxyalkanoate or triacylglycerol), glucogen or starch
what is a capsule?
protective gelatinous covering layer outside the bacterial cell wall
what is a microcapsule?
a bacterial capsule that is too thin to be resolved with the light microscope
what is loose slime?
soluble large-molecular material that may be dispersed by the bacterium into the environment
what are flagella?
- protein-based filamentous appendages that protrude outwards from the cell wall of bacteria
- organs of locomotion
what are fimbriae/pili?
- hair like structures on bacteria
- mediate adhesion via specific receptor-ligand interactions at their tip