Conjugation

Question 1

Donor cells possess?

Answer 1

Segment of F factor

Question 2

F factor -> F plasmid?

Answer 2

Circularises

Question 3

F plasmid consists of genes?

Answer 3

Req’ for the pdtn of sex pillus

Question 4

F plasmid is capable of?

Answer 4

Self-mobilising;

-> transfer itself to F-

=> 2 F+ cells

Question 5

F plasmid contain genes for 4 f(n)?

Answer 5

1. Express surface proteins on F+
   - > Sex pillus will not attach to other F+ cell
2. Synthesis sex pilus
   - > mating bridge formation
3. Code for endonuclease
   - > cut one stand at origin of transfer
4. Cont and regulate own replication
   - > copy no low

Question 6

F plasmid has?

Answer 6

Own origin of replication

-> control own replication by rolling circle mechanism

Question 7

Describe the process

Answer 7

F+ bacterium contains F plasmid and expresses sex pilus;

Sex pilus binds to complementary receptor on F- bacterium cell;

Sex pilus fuses with CSM on recipient cell;

cytoplasmic mating bridge;

endonuclease cleaves the origin of transfer on outer strand of dsF plasmid;

one strand of F plasmid is transferred from donor to recipient;

remaining F plasmid is used as template for DNA replication via rolling circle mechanism;

donated strand of F plasmid in recipient is replicated by lagging strand synthesis mechanism;

entire strand of F plasmid is transferred, recipient becomes F+ cell