ch 10 Flashcards
bacteria is good for research bc
- fast growth
- small haploid genomes (mutations), excellent tools (plasmids), genetic info all coded the same way
mutation
any change in DNA (spontaneous and induced), leads to genetic variation
changes in DNA sequence are
spontaneous, mutagen, transposons, horizontal gene transfer
auxotroph
cannot produce all building blocks needed for life
prototroph
can make all building blocks for life
how to find mutations
direct selection, enrichment methods, screening methods (replica plating)
direct selection
picking something based on what it can do (antibiotic resistance)
enrichment method
the use of certain growth media to favor the growth of a particular microorganism over others
replica plating
the stamping one
mobile elements are caused by
transposase
mobile/ transposable elements, needs
move about the genome and inserts itself, disruptive, terminal inverted repeats
mobile elements can carry
extra genes
site directed mutagenesis
mutate a gene exactly how you want
site directed mutagenesis steps
start with PCR and modded primer, introduce to strain of interest, recombination
repair of mutation methods
photolyases, excision repair, recombinant repair, sos repair
horizontal gene transfer types
transformation, conjugation, transduction
vertical gene transfer
the passage of a plasmid from mother to daughter cells during division
horizontal gene transfer
gene transfer in same generation
transformation
DNA (naked) from the environment that is recombine with DNA, natural or artificial, needs competent cells
transduction
DNA transacting particles transfer from bacteriophage,
generalized- any
specialized - specific
conjugation
DNA transfer with contact, bn donor (plasmid) and plasmid, pop mating types,
competent cells
alteration in the cell wall that make it permeable to large DNA molecules
recA protein
transformation protein that helps with recombinant
donor DNA from
dead cells, quorum sensing biofilms
competent cell generation
chemical (calcium treatment and heat shock), eletroporation
generalized transduction
all genes are equally likely to be transferred
phage relipcation, lytic/ virulent
makes hella viral chromes, cell lysis, cell dies
phage relipcation, temperate
inserted into host chromie (prophage), will jump out and lyse the cell when signaled to, death unnecessary
lysogen at - site
ATT
P22 bacteriophage
circular genome, can undergo rolling circle to replicate, infect salmonella, can get DNA recomb’d into genome
-% of p22 progeny have host genome particles
2
specialized transduction
transfer certain genes, due to excision errors in prophage (lysogenic to lytic) DNA,
specialized transduction is found in - phages
temperate
attB site
insertion of prophage
specialized transduction gal x gal
when when prophage with gal gene insert itself into a host with the gal gene too, unstable
specialized transduction gal x gal-
when when prophage with gal gene insert itself into a host without the gal gene too, gal is inherited and its it stable
conjugation donor and recipient
can be diff species, bacteria and euk
conjugative plasmid
carries genes for sex pili and transfer plasmid (f factor)
dissimilation plasmid
encode enzymes for catabolism of unusual compounds
r factors
encode resistance encoding genes (to antibiotics, heavy metals, and toxins)
Hfr f plasmid is located
in chromosome
gram postive conjugation
no pili, via clumping and use secretion to transfer DNA
e faecalis
gram pos conjugation
crisper original use
prokaryotic response to bacteriophage, cuts up foreign DNA
cas
cleaves foreign DNA
CRISPERs
cleaved DNA within organized clusters “archive”
palindromic are needed in crispr why
a group of enzymes recognize certain repeats, and break the DNA there to insert important information in the middle
spacers
complementary sequence fo foreign DNA
crispr other uses
downreg expression of genes, adaptive immunity, stress responses (repair), immunize bacteria, genetic engineering
CRISPR is transcribed as
a long precursor RNA (pre- crRNA)
CIRSPR can treat
sickle cell
Genetic Differences between prokaryotes
and eukaryotes
-DNA exchange not prerequisite for
reproduction in prokaryotes.
- If DNA exchange occurs, only small
section of DNA exchange in prokaryotes.
- DNA exchange in prokaryotes lots - only one in Eukaryotes
- Prokaryotes haploid bigger
Phylogenetic analysis
Relatedness / Similarity of
organisms
Phylogenetic analysis used for
Tracking sources of epidemics –disease epidemiology
– Changes in microbes over time
