1. Transduction

2. Is a type of horizontal genetic transfer
Donor DNA is picked up by a bacteriophage and released into the recipient cell
The recipient cell becomes a recombinant cell
The recombinant cell usually acquires new characteristics such as antibiotic resistance

3. Transduction Bacteriophage – Virus – infects bacteria
Transducing particle
Amp Res. gene

4. T4 phage that was used here to infect the E
T4 phage that was used here to infect the E.coli strains was grown in Ecoli that is resistant to amp resistance
Some of the transducing particles have amp res gene – lysate has phage and transducing particle
T4 phage has a mutation where a codon for an amino acid has been changed to a stop codon
UAG which is known as amber codon. Mutation that changes a sense codon to amber codon is known as amber mutation

5. Amber mutation prevents the synthesis of capsid protein of the phage such that phage cannot reproduce in a normal cell.
Stop codon stops synthesis of protein because no tRNA with complementary anticodon.
However transducing particle can inject the donor DNA into the recipient cell.
In the BE strain phage cannot reproduce, but transducing particle can make transductants (recombinant cells) that are amp res.

6. The cells that are growing on the amp medium
are transductants (recombinant cells). Normal cells are killed by amp not the phage.
Resistant to amp, received amp res. Gene from a transducing particle.
No phage plate – should be no growth . control to verify that without the addition on phage,
No amp res cells.

7. More colonies non dilute (10X) than 1 to 10
10X more colonies in 1:10 than 1:100

8. CR63 has amber suppressor mutation
Mutation in tRNA such that it has a anticodon complementary to the UAG (amber codon) which brings serine to the ribosome.
Capsid proteins are made. Phage reproduces and lysis of cells.
No phage – growth , see what a normal plate of CR63 looks like

9. Phage plate – less growth or no growth compared to no phage.
Most of the cells are being destroyed by phage.
Phage is killing the cells.