BIOL 322 FINAL EXAM QUESTIONS AND 100% CORRECT ANSWERS

What is a virus infectious agent nucleic acids present in viruses DNA (double) or RNA (single or double) but mostly RNA (nucleocapsids) viral lifestyle obligate intracellular parasites The 'virus early' hypothesis at the beginning there were replicative elements (BEFORE early life forms). Viruses evolved from this ancestor The 'regression' hypothesis degeneration of cells was basis for viral rise. Later, they acquired fully parasitic lifestyle The 'escaped genes' hypothesis simply acquired ability for selfish replication and spreading Virus invasion order 1. Attachment 2. Penetration 3. Synthesis (make copies) 4. Assembly 5. Release Divergent vs Convergent evo. Divergent: share same common ancestor Convergent: not same CA o most likely DIVERGENT due to accumulation of similar structural characteristics Lytic vs Lysogenic - Lytic is the active form of a virus when it is taking over host cells, causes it to burst/lyse - Lysogenic is viral DNA incorporated into hosts but is dormant until stress or some other stimulant, i.e. does not burst the cell without stress to make it become lytic. Bacteriophages viruses that infect bacteria (replicates within a bacterium). Can destroy cell wall from both outside and inside Bacteriophage example T4 in e coli. Significance of viral evo. o They help development (i.e. Viral Sunt Soil) o viral lysis increased DOM, which in turn increased metabolic activity in soil