bacterial structure metabolism and genetics Flashcards
spherical
1) cocci
rod shaped
1) bacilli
- diplo
- strepto
spiral bacteria
1) spiral
comma shape
1) vibrio
domain bacteria
1) proteobacteria
- largest bacterial phyla
2) firmicutes
3) actinobacteria
4) chlamydiae
5) spirochaetes
6) bacteriodetes
7) fusobacteria
etc
gram stain procedure
1) stain with crystal violet
2) iodine (fixative)
3) decolorizer
4) safranin red
gram - is pink
acid fast stain
1) for mycobacteria, which dont stain well with gram stain
gram positive cell wall
1) there is a thick peptidoglycan layer
peptidoglycan
1) provide shape, withstand tugor pressure,
2) composition
- peptidoglycan / murein
- part protein and polysaccharide
- NAG and NAM (N-acetyl groups)
- cross linked with peptides (DAP in gram-)
gram +
- pentaglycine bridge
gram-
-DAP
transpeptidases
1) penicillin binding proteins
2) link adjacent glycan chains
peptides bind to NAM?
teichoic cids
1) polymers of glycerol phosphate or ribitol phosphate
lipoteichoic acids
1) specifically binds to the lipid of cytoplasmic membrane
*both mediate attachment to cell surfaces
- lipopolysaccharides may induce septic shock by inducing IL-1 and TNF alpha production by macrophages
periplasmic space
1) gram - have cytoplasmic membrane and outer membrane
2) periplasmic space contains proteases and phosphatases, lipases, nucleases, and carbohydrate degrading enzymes
3) for metabolism?
4) might also contain virulence factors
- collagenases, hyaluronidases, proteases, beta-lactamases
- cause us disease
outer membrane
1) bacterial structure
cytoplasmic membrane
1) phospholipids and membrane proteins
lipopolysaccharides
1) 3 structural sections
- lipid A for viability and endotoxin
- core polysaccharide with Kdo sugar
- O antigen which is a polysaccharide which distinguishes serotypes of a species
outer memrban contains porins
1) diffusion of hydrophilic molecules less than 700 daltons
2) resistance to antibiotics via porin mutation
secretion systems
1) Sec is important for secretion
2) or there are sec-independent systems
capsule
1) gelatinous layer of polysaccharide
2) covers surfaces and mediates attachment to skin, heart, etc.
3) more virulent bc resistant to macrophages
4) determines serologic type
5) used to generate vaccines
flagella
1) pathogenesis in urinary tract
2) protein subunits called flagellin
3) propeller like motion
cytoplasm
1) extension microstructure
- microcompartments, inclusion bodies, and granules
2) bacteria may organize their cytoplasm using phase separated microorganelles
pili
1) hair like structures
2) attachment to receptors on human cells
3) f pili for bacterial conjugation
4) aka fimbriae
cell division
1) DNA replication
2) growth of cell
3) chromosomes
4) production of septum, and pinching to form 2
- the lipids of the pinched part fuse together
CFU count
1) colonies
do bacteria have a cytoskeleton
1) they have elements of it
2) FtsZ for cell division
3) MreB for cell widte and length
endospore
1) some bacteria make special form of peptidoglycan
2) for harsh environment
bacterial physiology
1) need nutrients from outside the cell => 12 precursor metabolites, ATP, reducing power
2) biosynthesis, polymerization, assembly, and bacterial cell formation
transport into the cell
1) outer membrane
- porin
- small size
2) cell wall
- mesh-like
3 major metabolic mathways
1 ) glycolytic
2) tricarboxylic
3) PPP
substrate level phospharylation
1) ADP obtains phosphate from metabolic intermediate
2) ATP is formed
TCA
1) conversion of molecules with enzymes at every step
2) CO2 and reducing power (NADH, FADN2)
3) ATP
PPP
1) ribose -5 - phosphate and erythrose - 4 - phosphate
precursor metabolites
1) there are a lot
chemiosmosis
1) reducing power is used to continue pumping protons out.
2) protein gradient (chemiosmotic) allow atp synthase to place phosphates on ADP
3) if you add a protonophore, the bacteria would die due to lack of ATP generation from the gradient
oxygen use
1) obligate anaerobes
2) obligate aerobes
3) facultative anaerobes
frederick griffith
1) transforming factor which can be taken from virulent bacteria and make non-virulent bacteria turn virulent
2) could make a capsule
DNA replication
1) AT and GC
2) DNA polymerase III binds nucleotides releases pyrophosphate
3) semiconservative
- replication fork
- one direction 5->3
4) leading and lagging strand
regulation of gene expression
1) inducible genes
2) repressible genes
when glucose is exhausted
1) growth stops but begins at slower rate using lactose as energy
- lac operon: lacZ, lacY, lacA
- regulated by lacI
2) when no lactose
- repressor binds, stops transcription
3) when lactos
-repressor gets bound by product of lactose
gene exchange
1) transformation
- DNA enters
2) transduction
- phages
3) conjugation
- plasmid
plasmids
1) circular DNA 1.5-400 kbp
2) resistance to toxins or antibiotics
3) fertility factor for conjugation
4) bacteriocins
- toxins
