BACTERIOPHAGE VIRUS

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Multiply within bacteria eg. E.Coli

Isocohedral head and helical tail

Contain DNA

Phage rep time: 20-40 mins (50-200)

Lytic Cycle: Virus goes inside, multiplys and release

Lysogenic Cycle: Virus DNA becomes part of host DNA and grows

LYTIC CYCLE:

Attachment: binds the receptors on bacterial cell wall

Penetration: genome is injected

Early replication: Genome starts to replicate and other components develop

Late replication: Production of components progress aswell as enzymes

Maturation: components are now assembled

Release: Phage coded, enzymes breakdown peptidoglycon in bacterial cell wall causes lysis

Some phages don't cause lysis/death: lysogenic cycle

Lysogeny: conclusion in which bacteria/viruses can coexist without damage to each other

Virus incorporates it's DNA/RNA into a chromosome of the host cell

Each time a cells chromosome is reproduced the virus is also propgated

LYSOGENIC CYCLE:

Host DNA is not destroyed and viral genome remains latent in the cell

Inactive phage = prophage

Prophage codes for proteins that suppress prophage genes and renders bacteria resistant to more of the same phages

Prophage can be activated and excised later to enter a lytic cycle

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