Bacterial conjugation

Question 1

what is bacterial conjugation

Answer 1

mechanism of bacterial gene transfer via direct contact of bacterial cells throgh sex pilus

Question 2

what does conjugation require?

Answer 2

• pilus-dependent contact between donar and recipient cell
• fertility factor (F factor): which is an episome, contain genes required to establish conjugation

Question 3

what is an episome

Answer 3

• plasimid/extra-chromosomal DNA capable of self replication
• can either be free in the cytoplasm or integrated into the bacterial chromosome

Question 4

what genes does F factor contain that allow establishment of conjugation?

Answer 4

tra genes: encodes proteins that assemble to form pilus

ori: replication origin, required to be maintained within the population

oriT: origin of transfer, initiates DNA transfer

Question 5

how does the pilus facilitate DNA transfer?

Answer 5

• pilus contract, reduce distance between 2 cells, bring cells into direct contact
• relaxase cuts F plasmid, opens F plasmid into ssDNA, binds to 5’ end of ssDNA, bring 5’ end to machine that transfer DNA across cell envelope
• energy of process comes from ATP hydrolysis