33 Transduction and Bacteriophages

Question

Answer

What is transduction?

Transfer of bacterial DNA between cells by bacteriophage particles.

What is a bacteriophage?

A virus that infects bacteria.

Why do phages depend on bacterial hosts?

They lack ribosomes and their own energy-producing machinery.

What does a phage first recognize on a host?

A bacterial surface receptor or protein.

What does the phage inject into a host?

Its genome.

What is the lytic cycle?

Phage replication and assembly followed by lysis of the host and release of virions.

What is the lysogenic cycle?

Phage DNA persists in a host, often integrated as a prophage, without immediate lysis.

What is a prophage?

Phage DNA maintained within a bacterial host during lysogeny.

How can transduction occur?

A phage mistakenly packages or carries bacterial DNA and delivers it to another bacterium.

What is generalized transduction?

Transfer of potentially any bacterial DNA fragment due to accidental packaging.

What is specialized transduction?

Transfer of bacterial genes near a prophage integration site after faulty excision.

How can bacteria defend against phages?

Restriction-modification systems can recognize and cut foreign DNA.

What does methylation do in restriction-modification defense?

Marks host DNA to help protect it from the host restriction enzyme.

Does transduction require a sex pilus?

No; it uses a phage rather than conjugation machinery.