1. Viruses Are obligate intracellular parasites
Some are small as ribosome
Some bigger than some bacteria

3. anatomy of a virus All contain a sort of genetic material
Could be DNA (single or double stranded)
Could be RNA (single or double stranded)
All contain a protein coat enclosing the genetic material=capsule
Some have a viral envelope that is derived from a host cell membrane

5. BACTERIOPHAGES (Phage) are the best understood viruses
An example of a phage is the T4 phage
Its life cycle always results in the death of host cell
This cycle is called the lytic cycle
If this is the only life cycle the phage is a virulent phage

6. Viral life cycles

7. Lysogenic cycle -temperate phages -DNA is incorporated into
host genome
-called prophage
-may enter the lytic cycle
-environmental triggers

10. Viral envelopes
Have glycoproteins that help bind to cell membrane
Capsid enters cell
Genetic material copied
New capsid proteins made
Glycoproteins produced in ER
Viruses bud out of cell

11. Retroviruses
Single stranded RNA that acts as template for DNA