bacterial genomes contain fewer genes and base pairs in haploid genomes than other organisms
haploid genome of most bacteria allows all mutations to be observed directly, w/o interference from dominance interactions between alleles
rapid generation times
bacteria produce prolifically, generation time is measured in minutes
large # of progeny
large number of clonal progeny can be examined, increasing likehood that statistically rare events will be observed.
ease of propagation
microbes grow in liquid or culture plates. cultures are easy and enexpensive to maintain, require little lab space.
numerous heritable differences
mutants easily created, i.d, isolated, and manipulated for examination.
transfer of replicated DNA from donor bacterium to recipient
uptake of DNA from environment by recipient bacterium
transfer of DNA from donor to recipient by way of viral vector
closed circular molecule of double-stranded DNA.
small double stranded circular DNA
Contains nonessential genes, used infrequently or under special conditions.
kind of plasmid
contains genes that promote own transfer from donor bacterium to recipient.
kind of plasmid
carries antibiotic resistance genes, can be transferred from donors to recipients.
process of gene transfer
transfers some of its genetic information to other cell,(RECIPIENT CELL)
aka conjugation tube
genetic information travels thru this to recipient cell.
connectes donor to recipient
3 kinds of cells seen in conjugation
donor cell-contains F plasmid
recipient cell-receives DNA does not contain f factor
exoconjugant cell-produced by conjugation.
produced by conjugation, is essentially recipient cell that has had its genetic content modified.
insertion sequence elements
mobile segments of bacterial DNA that are capable of transporting themselves throughout bacterial genome.
Circular DNA elements like plasmid
can replicate independently of bacterial chromosome
can integrate into bacterial chromosome and replicate as part of chromosome
f factor produces such protein after contacting conjugation pilus
binds to origin of transfer (oriT)
rolling circle replication
unidirectional mode of DNA replication used to replicate circular plasmid, in which replicating circular molecule appears to reel off its nontemplate DNA Strand, using other as template for replication
origin of transfer (oriT)
site within fertility factor sequence where transfer to recipient cell is initiated.
high frequency recombination
donor bacterial strain containing and f factor integrated into its chromosome.
AKA hfr chromosome
selective growth medium
contains compounds that permit only ex-conjugants with specific genotypes to grow,
prevent growth of donor cell recipient cells
cessation of cojugation caused by breakage of conjugation tube
stops conjugation before Hfr chromosome can be completely transferred from donor to recipient.
time of entry maping
kind of experimental strategy that can map the order of donor genes and to determine the distances between genes
contains functional but altered f factor derived from imperfect excision of the F factor out of the Hfr chromosome
donor cells carrying an F' factor
exconjugant bacterium that acquires a second copy of one or more genes by conjugation with an F' donor cell
six step process in which bacteriophages seek out and attach to host cell.
leads to lysis of the host cell
lysis releases up to 200 progeny phage particles
lytic cycle steps
attach- phage to host cell
Injection- phage chromosome into host cell
replication- of phage DNA, copy of phage chromosomoe is required for each of phage progeny
Transcription and translation of phage genes
packing of phage chromosomes into phage heads
lysis of host cell
bacteriophage can integrate into the bacterial host chromosome and produce either lytic or lysogenic life cycle
life cycle of bacterium infected by a temperate bacteriophage that integrates into the host chromosome and replicates along with it.
comes to an end
can persis for many bacterial replication and division but ends
characterizations of lysogenic cycle
attachment of phage to host
injection of phage chromosome into host
integration of phage chromosome into host chromosome
excision of prophage
resumption of lytic cycle
bacterium that is product of transduction
transduction of a random segment of a donor chromosome into a recipient cell by a transducing phage.
transfer of any bacterial gene, can be accomplished by bacteriophages that dont descriminate between phage and host DNA
accomplished only by temperate phages, genes are limited tho those close to site pf prophage integration.