Microbiology Flashcards
Prokaryotic
- Nucleoid (double stranded DNA)
- 70s
- Cell membrane
- Cell wall (peptidoglycan - may be degraded by lysosomes)
- Flagella/pilli
- Plasmid (addition DNA capable of autonomous replication in g-ve)
- Mesosome (vesicles formed by invagination of plasma membrane - cell wall formation/chromosome rep)
What does pro lack that eu has
Nuclear membrane
Membrane-bound organelles
Nucleolus
peptidoglycan
- provides rigidity
- important for rep and survival in hostile conditions
- infection causes peptidoglycan to interfere with phagocytosis, stim mitosis of lymphocytes and becomes pyrogenic
g+ve
predominantly aerobic
- turns purple with stain (trapped in THICK pep wall)
g-ve
predominantly anaerobic
- counterstained into red
- THIN pep wall
bac cell division
= binary fission
- septum (cross wall) produced
morphological classification of pro
from incomplete cleavage of septum
coccus → spherical (staphylococcus)
bacillus → rod-shaped (e coli)
spirillum → snake-like/helical (t pallidum)
spores
g+ve (NOT g-ve)
- encases bac/fungal → resistant to env factors
- DORMANT
morphological classification of bac
- coccus (spherical) - staphylococcus (chain); streptolococcus (cluster)
- Bacillus (rod-shaped) - e.coli
- Spirillum (helical) - T.pallidum
virulence factor of bacteria
invade, infect, evade
local effects of bac
- prod enz (exotoxins→prod by g-/+ve)
- damage host cells & cellular components
- forms an abscess (from pus prod bac)
systemic effects of bac - septicaemia
wide spread destruction caused by absorption of bac/toxins in blood
systemic effects of bac -endotoxin
released by g-ve → triggers immune response → BV dilated → sepsis
virus capsid
protein coat containing nucleic acid genome
- withstands harsh env
virus envelope
lipid membrane coat
- maintained in aq solution→transmit via fluids
genetic form of viruses
DNA or RNA
function of viruses
true parasites
- insert genome→hijack host cells→replicate→damage/kill cells
viral rep
early phase - penetrate membrane→ release genome
late - genome rep
latent - extracellular infectious viruses not detected
viral pathogenesis
acquisition - entry into body
1o site - infection/inflam
2o site - virus amplified & spread→ the incubation period
what is convalescence
body repairs the damage
herpes simplex viruses type 1 (HSV1)
normally benign, but life threatening in newborn or immunocompromised person
rubella in pregnant women
genetic malformation in fetus → developmental effects
fungi
- non-motile, aerobic (yeast)
- reproduce by forming spores → increase surv and spread
pathogenesis of fungi
mycoses (fungal infection)
- penetrate, colonise, repro
