Virus

Nota:

• they can exist outside host cell and doing nothing. but they reproduce inside host cell

1. can't produce ATP on their own
2. not cellular

Nota:

• may need some reading abt the hypothesis

1. – escaped-genes hypothesis
2. – degradation hypothesis
3. – RNA world-origin hypothesis

1. increase diversity of life
2. genetic info research
3. infects all form of cellular life
   1. each human cell can be infected by at least one type of virus
      1. how to prevent viral infection
         1. get vaccinated
         2. antiviral drug
            1. interfere virus genome replication

1. Ebola

1. AIDS

1. nonenveloped
2. enveloped

Nota:

• single/double stranded linear/circular 

1. DNA
2. RNA

   Nota:

   • Could be double or single stranded.  most RNA(not just abt virus) are single 
   1. +ve sense
   2. -ve sense
   3. ambisense
3. how do virus copy their genome
   1. RNA replicates function as RNA dependent RNA polymerase
   2. reverse transcriptase
      1. use RNA as a template to produce DNA

1. lytic cycle

   Nota:

   • produce virons and kill host cell
2. lysosome

   Nota:

   • no virions produced have dormant stage in host cell
3. 6 common phases
   1. 1.attach to a host cell and enter into cytosol
      1. 2. transcription of viral genome and production of viral protein

         Nota:

         • – host cell machinery used for translation – some viruses have proteases to cut their own proteins
         1. 3. replication

            Nota:

            • – host cell supplies nucleotides – RNA genomes have RNA replicases – retroviruses have reverse-transcriptases
            1. 4. assembly of new generation of virions

               Nota:

               • – genome packaged into capsid 
               1. 5. exist from the infected cells
                  1. 6. transmission to a new host
                  2. budding (enveloped virus)
                  3. bursting (naked virus)
      2. plant virus:
         1. insect biting the plant; the cell wall disrupted, virus come in
      3. animal / bacteria virus
         1. attach to a specific molecule on cell wall / plasma membrane