reintroduction to microbiologie Flashcards
microorganisms
Eukaryotes
- protozoa
- fungi
prokaryotes - bacteria
viruses
prions
protozoa
unicellular eukaryotes
often affect immunocrompomised
many free living
funig
eukaryotic different froms external rigid wall of chitin filamentous or yeast forms dimorphic if display different forms
bacteria cellular forms
cocci diplococci tetrags sarcina streptococci staphylococci bacilli extended irregular rods kidney bean corkscrew helical
gram +/-
Gram + - purple - retain gram stain - 1 membrane - peptidoglycan outer layer i.e. cell wall Gram – - pink - 2 membranes - inner and outer membrane - periplasmic space between - LPS on the outside
peptidoglucan
- polymer of N acetyl muramic acid and N acetyl glucosamine
- crosslinked via amino acid pentapeptides and anchored to cell wall
pili and fibriae
- proteinaceous filamentous structures
- often used for attachment to host cells or surfaces
pathogen
disease causing bacteria
opportunistic
commensals that sometime cause disease
e coli
gram - rod
commensal
bacteriodes
gram - anaerobic bacilli
clostirdal
gram + anaeboic spore forming bacilli
mycobacteria
thick cell wall of mycolic acid (waxy nature)
ziehl Nielsen stain red
cannot be stained with gram +/- stain
chlamydia
obligaet
gram - cell wall
viruses
obligate intracellular paracites
viral genome uses host to encode viral protiesn
basic viral structure
nucleic acid encapsulated by proteinaceous capsid
varying shape and symmetry
some have lipid coat
lytic life cycle
- virus attaches to cell
- endocytosis
- uncoats
- replicates genome via host mechanisms
- threshold reached and bursts
viral latency
Infection does not result in lytic life cycle
1) incorporation into genome – retrovirus
2) latent infection of host cell away from site of infection eg herpes
prions
heat resistant
Normal PrPc converted to rogue
aggregate into long fibres and amyloid plaques
