HomeHelpContact usBack

Modules Open College - e-Learning Content Library
 
Bacteriophages
 

Bacteriophages are viruses that infect bacteria and dwell inside them. Press "Run" button. Observe the phage approaching the bacteria and its tail strands becoming connected to the receptors on the surface of the bacterial cell. Under the impact of the lysozyme ferment, the cell membrane of the bacteria softens up. The tail-case of the phage softens, and the hollow shaft enters the host cell. The bacteriophage DNA enters the bacteria.

The DNA of the virus proceeds to encode the synthesis of ferments, using ribosomes of the host to do that. Initially, the bacterial DNA is suppressed by the intruder, and after some time the phage ferments break it up altogether. The bacteriophage DNA replicates and encodes the synthesis of the capsule's new proteins. As a result of its self-replication inside of the cell, new phage particles are formed around the phage DNA, and a lysozyme is synthesized. Approximately half an hour after the virus attack the membrane of the bacterial cell disintegrates under the impact of the lysozyme; several hundred new phages leave the destroyed cell and infect a new one.

Some phages (known as "moderate phages") do not replicate after they infiltrate the bacteria. Instead, their DNA becomes a part of the host's DNA, where it stays for several generations, and replicates alongside the host DNA. The life cycle of such bacteriophages is called "lysogenic".

Press "Stop" button to bring the animation to a halt. Press "Reset" to return the model to its initial state.

 
© OpenTeach Software, 2007