December 3 Notes

III. a) Why viruses are specific to particular host cells is because only some kinds of cells have the "correct" surface proteins for viral proteins to attatch

c) Replication of nucleic acids
-viral nucleic acids copied by host cell enzymes, ect.
i) DNA viruses
ex. smallpox
*have DNA genomes
*host cell DNA polymerase copies viral DNA
ii) RNA viruses
ex. flu
*have RNA genome
*no living thing has an enzyme that copies RNA to RNA
*RNA replicase= RNA virus specific enzyme that copies RNA to RNA
*first step in copying RNA: translation of RNA replicase gene by host cell ribosomes and RNA
iii) Retroviruses
ex. HIV
*also have RNA genomes
RNA genome-> DNA copy (becomes part of host cell DNA)--> RNA
*reverse transcriptase= enzyme specific to retroviruses, copies RNA to RNA

d) synthesis of viral proteins
-virus uses host RNA polymerase, ribosomes, tRNA and amino acids to make its capsomeres, glycoproteins, and other viral-specific proteins

e) Assembly of new virions
-once you have all the bits, new virions spontaneously self-assemble

f) Release of new virions from host cell
i) lysis of host cell: host cell blows up, releasing new virions into the environment
ii) budding from host cell: enveloped viruses use glycoproteins to wrap selves in host cell membrane and tear free

Danya Hangman

Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License