Chapter 18

Viruses:
~ the genetic make-up can be double or single stranded DNA or RNA
~ enclosed by protein shell (capsid)
*has receptors so it knows what host to accept
*envelopes surround capsid and aid in infecting the host
Lytic cycle
~only reproduce within a host (most only reproduce within a certain host)
~the reproductive cycle ends in the death of the host cell
1. attatches to host cell with receptors
2. injects viruses Dna into cell
3. replicates its own DNA into host
4. new phages are assembled
5. produce lysozome (disintegrates cell wall; cell dies)
6. the new phages are released ~viral DNA (prohage) when integrated into bacterial chromosome's DNA

http://www.youtube.com/watch?v=wVkCyU5aeeU&feature=fvw


Lysogenic cycle
~the phage DNA becomes part of the host and is replicated
~ more dormant (cell is not killed with reproduction)
~ can move into the lytic cycle

http://www.youtube.com/watch?v=_J9-xKitsd0