Ch10 Flashcards
Typically how many copies of a genome do bacteria and eukarya have?
1; more than 1
Joshua Lederberg
got Nobel Prize for discovering bacterial gene transfer
nutritional mutants
What is the other name for them
strains of microorganisms (unlike wild-type organisms) that only replicate when they get specific things that the normal strain has
auxotrophs/ auxotrophic mutants
reversion
spontaneous mutations of (auxotrophs) nutritional mutants results in the ability to make the necessities it needs without other bacterial help
(very low frequency to the point it wasn’t considered in Lederberg experiment)
for example, a growing culture of auxotrophs that need methionine in order to grow, later some that have a few that have methionine
What did Lederberg do to solve the issue of the reversion of auxotrophs?
He used strains with more than one nutritional mutation (more requirements)
plasmids
circular DNA independent of the bacterial chromosome
not needed for the cell to live unlike chromosome
replicates independently (has genes for antibiotic resistance & toxin degradation)
genome
all hereditary information of bacteria (chromosome and plasmids)
replicon. Give examples
DNA material that has one origin of replication in which it replicates from
(an example is a chromosome and a plasmid of a bacteria)
copy number
set number of plasmid molecules in a bacterial cell (numbers vary per type)
plasmid incompatibility
How can plasmids coexist in a cell?
different plasmids of the same cell are unstable
(this is due to similar replication mechanisms like the same origin of replication)
plasmid replication is random and cell is confused (sees both plasmids as the same) one plasmid always beats the other (losing plasmid gets lost)
Plasmids MUST be in different incompatibility groups to coexist
alleles
genotype
form of a gene (bacteria have one eukarya have 2 usually
describes an allele
replica plating
used in order to select intended strains unnoticed by phenotypic selection
clones
genetically identical organisms that originated from a single cell
Briefly go through the process of a restriction enzyme
cleave different DNA at specific sequences (restriction sites)
result in DNA fragments with sticky ends used for recombinant DNA (unnaturally existing DNA made in laboratory; in vitro) then glued together by DNA ligase
cloning vector (name three types)
where DNA is manipulated
plasmid
phage
cosmid
Briefly explain the process of homologous recombination
What would be the difference between the distribution results of prokaryotes and eukaryotes?
RecBCD nics DNA
RecA causes strand invasion and rejoins strands, resulting in holiday junctions
results in prokaryotes are even distribution (circular)
unequal distribution is the result of eukaryotes
What is non-homologous recombination?
exchange of DNA pieces that are not similar sequence-wise (usually with viruses and transposable elements)
knockout mutation
suicide plasmid
mutations (recombination) utilized to disrupt genes
a plasmid vector that does not replicate when in a target cell
transformation
when an organism is referred to as competent what does this imply? can this be influenced?
where organism takes DNA from the outside environment
means the organism can take free DNA from its surroundings
electroporation and calcium chloride solutions can cause a cell to be competent
conjugation
what is conjugation capable of doing?
the specialized transfer of DNA from one cell to another through contact (larger segments tend to be transferred FYI)
can transfer virulence factors making a normal cell lethal
F plasmid
(fertility factor) circular plasmid affiliated with conjugation
