Powerpoint 27 Flashcards
The transfer of naked DNA from one bacterium to another
DNA mediated transformation
discovered by Fredrick Griffith while working with Streptococcus pneumoniae
DNA mediated transformation
only form of gene exchange in which donor survives
conjugation
requires DNA sequences for formation of pili
-can be on plasmid of in chromosome
conjugation
required direct contact between cells
conjugation
cells must be of opposite mating types
conjugation
these cells in conjucation carry a plasmid that codes for fertility factor or “F factor”
-this cell is designated F+
donor cells
these cells in conjugaton do not carry a plasmid
-this cell is designated F-
recipient cell
the ____ organism has everything it needs
- origin of replication
- origin of transfer
- genes encoding for the sex-pilus
F+ organism
why do it?
because plasmid or associated information can give you an advantage e.e. antibiotic resistance (R-plasmid)
the plasmid id replicated in the donor cell and is transferred to the recipient
during conjugation
In some of these cells the F factor integrates into the host chromosome
-converts F+ to Hfr= high frequency of recombination
F+ cells
Conjugation between Hfr and F- cell results in only
a portion of the F factor being replicated and transferrred fo F- remains F-
-F- has new information by may not have the F factor gene
can conjugate to plan cells
Agrobacterium tumefaciens
Transfer of ____ or ___ is integrated into plant genome
- parasitic iteraction
- crown gall disease
- genetic manipulations of transgenic plants
DNA or T-DNA
bacterial DNA that is transferred from donor to recipient via a bacterial virus (bacteriophage)
transduction
two types of transduction
Generalized
Specific
any gene of donor can be transferred
generalized
only specific genes can be transferred
specialized
The phage accidentily pakages host genomic DNA
- SAlmonella phage P22 recognized a pac site to teminate packing of own DNA
- 1% population misread the pac site packaging from host chromosomal DNA
generalized transduction
Mistake in packaging results in transfer of donor DNA but No phage AND so recipients will never become a donoe
-free new DNA
Generalized
only specific genes can be transferred WITH the phage DNA so the recipient will eventually become a donor
-ticking time bomb but some cool info in the short term
Specialized
replication erros
vertical transfer
PROOFREADING to ensure all the corect information is given to the daughter
- a limiting factor in cell division
Replication: DNA to DNA
REGULATED only make the mRNA’s you need at the time
-some are needed constantly
Transcription
: DNA to RNA
COUPLED to transcription in prokaryotes
Translation: RNA to protein
conjucation, transformation and transduction
horozontal gene transfer
