-
cell division
- binary fission
- budding
- mitosis
- meiosis
(incomplete seperation is what leads to diplo, tetra, palisade, etc.)
-
Lag Phase
(bacterial population growth curve)
individual cells are growing but haven't divided yet
-
Log Phase
(bacterial population growth curve)
Cells growing exponentially
-
Stationary phase
(bacterial population growth curve)
dying as fast as they are dividing
-
Decline/Death phase
(bacterial population growth curve)
- -pH changes from waste of dying bacteria
- -no cells are divinging anymore
-
Medium:
agar
solid - complex of CHO from marine algae
- plates: ideal for isolating cultures
- Stabs: find out if the bacterium is motile
- Slants: (if lucky) can isolate individual colonies
-
Medium:
broth
- liquid
- bacteria grows quickly
- shows different patterns of arrangement from plates
- always define shape from broth because it would be the same every time
-
Medium:
natural
soil, living or dead tissue
-
Medium:
synthetic - defined
every batch identicle
-
Medium:
synthetic - undefined:
- blood, beef extract
- variations from sample to sample - but we know whats in it
-
Medium:
selective
promotes growth of some but inhibits growth of others
-
medium:
differential
color or medium change to let you know something is happening
-
Medium:
enrichment
- fosters growth of bacteria - fastidious
- ones that can't grow need something to help
-
mannitol salt agar
synthetic, selective, not enriched, differential between 2 staph species
-
blood agar
- synthetic
- not selective. al bacteria grow
-
pH:
acidoohile
grows in acidic
-
pH:
neutrophile
grows in neutral conditions
-
pH:
alkaliphile
grows in basic conditions
-
temperature:
psychophiles
grows in cold condition
-
temperature:
mesophiles
grows in moderate condition
-
temperature:
thermophiles
grows in ht conditions
-
oxygen:
obligate aerobes
needs oxygen
-
oxygen:
microphiles
small amount of oxygen
-
oxygen:
facultative anerobes
with or without oxygen
-
oxygen:
aerotolerant anerobe
doesn't need oxygen but can live with it
-
Oxygen:
obligate anerobes
doesn't need oxygen
-
Osmotic pressure
- water follows salt.
- needs to have water for metabolism
- to high of a salt concentration outside water will leave bacterium
- with no fluid cytoplasm - organelles can't move around
-
Bias in culturing
- most microbes can't be cultered
- don't know what the culture needs
- can't count them
-
DNA replication
- semi-conservativ
- complementary base pairing (A--T & G---C)
- process enzyme mediated
-
Gene expression
happens at all times (product = proteins)
-
Feedback inhibition
final product of protein synthesis inhibits the starting enzyme
-
Enzyme induction
protein makes promotor site on DNA more accessible
-
Enzyme repression
protein blocks transcription
-
genetic variations
gives a population the ability to survive when the enviroment changes
-
Population:
group of the same species living in the same area at the same time
-
Biological species concept
group of individuals that reproduce sexually with each other (and produces viable healthy offspring)
-
Species (bacterial)
- unique phenotypic properties
- >70% DNA homology among strains
-
Strain
descendants of a single isolation in a pure culture
-
Mutations
- subsitution: nucleotide changes
- deletion: nucleotide removed
- insertion: nucleotide added
- inversion: nucleotide flips and re-inserts itself
- transposon
-
effect of mutation:
non-function
can't be transcribed
-
effects of mutations:
slight change
- similar enzyme made
- reaction slows
-
effects of mutations:
big change
- different enzyme produced
- or codon changed to stop codon
-
effects of mutation:
no change
3 codons still make same enzyme
-
Vertical gene transfer
- sexually reproducing
- binary fission
- recombination
-
horizontal gene transfer
- asexually
- transformation
- transduction
- conjugation
-
transformation
bacteria uptakes naked DNA from other bacteria so they then have the genes
-
Transduction
- DNA from bacteriophages
- bacteriophages binds to cell based on surface enzymes
- injects it's DNA
- host cell makes more pieces and they're released
- some may also contain bacterial DNA
-
conjugation
- closest to sexual reproduction
- plasmids project receptors on their surface so they know which cells have the plasmid.
- when they find a cell that doesn't have the plasmid they bind to each other and the plasmid injects a strain into the cell
- a complimentary stad is made
- each cell has a copy
-
classification of bacteria
- morphology and stains
- growth characteristics/colony morphology
- nutritional needs
- biochemical tests
- DNA sequencing
- phage typing
- rRNA sequencing
|
|