exam three (genetic mutation) Flashcards
heritable changes in DNA (mutant vs. wild type)
mutations
mutation of single base pair (does not always cause problems)
point mutation
______ mutations in prokaryotes happen because they replicate much faster; polymerase is more error prone
spontaneous
mispairing of nucleotides mutation
base changes
strand slipping causes ____ or _____
insertions or deletions
___ ___ are random and can be selected for by some kind of pressure (naturally) can be advantageous or detrimental
spontaneous mutation
reversion mutation or suppressor mutation causes what
mutant —> wild type
(reversion mutation) a second mutation at the same original mutation site changes ____ and ____ back to normal
genotype and phenotype
in the suppressor mutation ( not at original mutation site) genotype is mutated twice but only changes ____
phenotype; the surpressor mutation ends up cancelling out original mutation
mutant gene leads to mutant ____ leads to phenotypic difference
protein
lethal mutation, morphology, conditional mutants, biochemical and resistant mutant all cause
phenotypic changes
microbe unable to grow in absense of molecule
auxotroph
isolating a mutant will allow direct selection of mutation (mutant will have “selectable” quality; such as resistance to certain antibiotic)
mutant isolation
only mutants will grow in presense of ____ quality (mutation)
selectable
grow microbes under non-selective conditions; then take bacteria which have specific changes and grow them on selective media and non selective; what is this called
replica planting
a resistant colony would ___ and the non resistant would be
alive; not growing
transfer of genetic material between organisms (not direct descendants)
horizontal gene transfer
transformation, cojugation and transduction are all ways to do
horizontal gene transfer
in griffiths rough strain, smooth strain DNA was passed by
homologous recombination
in homologous recombination DNA segments are recombined; integrate ___ DNA and repair strand breaks
new
homologous recombination requires exact same ____ sequence (where the specific mutation is)
DNA
the smooth strain has a portion which encodes for a ____; rough strain did not have this gene (only capsule is changing with homologous recombination)
capsule
the capsule of smooth strain was protective and made it impossible for mice to ______
(polysaccharide in capsule makes colonies look smooth (S.pneumonia)
defend against it
with homologous recombination ____ strain is able to pick up capsule gene
rough
homologous recombination can be a complete ___ or just a ____
transfer; patch
rec a ___ recombination event (recombinase)
drives
random bits of DNA, phage DNA, and plasmids are _____ DNA; they are transposable elements
mobile
plasmids can be ____ into chromosome and in genome but still not needed
integrated
“jumping genes” - do transposition; they integrate into another DNA molecule through insertion sequences
transposable elements
only about 1000 base pairs and flanked by inverted repeats; have transposase genes
insertion sequences
longer; have 2 identcal insertion sequence elements with genes in the middle (can be antibiotic resistance genes)
transposons
short target sequence; transposase makes double stranded break in target; transposon is placed into new DNA and target sequence is _____ during transposition on either side of transposon
duplicated
known as “cut and paste”; transposon jumps from donor DNA to target DNA
conservative transposition
known as ‘copy and paste’; transposon copies and moves to target sequence but stays in original chromosome
replicative transposition
transfer of free DNA fragment
transformation
direct transfer of DNA between microbes
conjugation
transfer by phages of DNA
transduction
plasmid and transposon are examples of
free DNA
a ____ cell is receptive to new DNA (this type of cell will take up free DNA)
compotent
streptococcus and neisseria are not competent; true or false?
false
the naturally competent species produce receptor proteins and have ___ ___
uptake systems
what ways can competent be induced
manipulating membrane by electric shock ot calcium chloride
transfer of DNA directly between bacteria (donor and recipient); often how plasmids are transferred
conjugation
the ___ plasmid is transferred by conjugation and has a sex pilus
F
the F+ is a microbe that has
sex pillus and F plasmid
F+ microbe attaches sex pilus to F- and then pulls it closer for direct contact; end result?
tranfer of plasmid; two F+ microbes
___ plasmid integrates into host chromosome; waits for conjugation (takes host genes with it)
F
f plasmids are called ____ because they bring with them a lot of different genes
hfr (high freq. recombinants)
