Chapter 7.7, Problem 1COMQ

Summary Introduction

Introduction:

Bacteriophages are viruses which infect the bacterium and replicate inside it.

Once a virus exists in a host cell, it goes either one or two cycles. Viral reproduction has two types of cycles- lytic and lysogenic.

The lytic cycle is a type of viral reproduction which lyses the host cell, the host DNA is hydrolyzed, and Viral DNA independently replicates from the host cell. Generally, such type of reproductive cycle is shown by a virulent phage. Bacterial plaque is a clear region in a bacterial lawn where the bacteria have been lysed by a virulent phage.

The lysogenic cycle shows the integration of Viral DNA to the host DNA, and then replicates it along with the host genome. The host’s cellular mechanism is marginally altered by the viral genome. Generally, such type of reproductive cycle is shown by a non- virulent phage. Transduction is the process of transfer of foreign DNA into a cell.

Temperate bacteriophage follows the life cycle that shows the integration of their genome in the host cell.