Genetic Transfer Systems Flashcards
What are the THREE mechanisms that bacteria are able to acquire genetic information from their environment or from each other?
- Conjugation
- Transformation
- Transduction
What is Conjugation?
Transfer of DNA involving direct cell-to-cell contact mediated by pili
What is Transformation?
Uptake of free exogenous DNA by a bacterium
What is Transduction?
Transfer of DNA from one bacterium to another by a bacteriophage
What are the THREE outcomes for recieved DNA?
- Exist autonomously in cytoplasm of recipient
- Integrated into recipient chromosome
- Replace homologous DNA of recipient
What is the Recipient?
Bacterium that RECIEVES DNA
What is the Donor?
Bacterium that DONATES DNA
What is Homologous DNA?
Regions of DNA which are very similar between donor and recipient
Can DNA move unidirectionally or bidirectionally between bacterium?
DNA always moves in one direction
What do a Donor and Recipient together make?
Mating pair
What factor do E. coli donor cells contain?
F-factor
What is an F-factor?
Genetic element (plasmid or episome) capable of conjugative transfer
How many genes are contained in an F-factor?
20 tra genes, involved in DNA transfer
What proteins do tra genes encode for?
Proteins required for the synthesis of specialised appendages (e.g. Pili)
What are the functions encoded by the F-plasmid?
- Attach donor to recipient
- Provide a channel through which genetic material can be passed
- tra genes also confer surface properties on donors that prevents contact with other donors