Lecture 40 - Viral Biosynthesis Flashcards
what is the goal of biosynthesis
generate components to assemble viral progeny
in a DNA genome, whose enzymes are used
cell - DNA to mRNA
cell or viral - DNA to DNA
in a RNA genome, whose enzymes are used
viral - RNA to RNA
in a retrovirus, whose enzymes are used
viral - RNA to DNA (reverse transcriptase)
viral - integration (DNA to viral DNA)
cell - viral DNA to RNA
what copies RNA genome into a DNA copy in a retrovirus
reverse transcriptase
what cuts cell DNA and inserts viral DNA in retroviruses
integrase
T/F: integrase determines mutation rate
FALSE - polymerase type
T/F: RNA polymerases have a higher error rate because they lack exonuclease
TRUE
what is the function of exonuclease
proof-reading
why is it difficult to “cure” HIV?
integrated to cell genome
what are the 3 steps of biosynthesis
- generate mRNA
- translate mRNA to generate protein
- replicate viral nucleic acid
viruses with a ____ genome can use ____ enzyme
DNA; cell
what kind of drug should be used for viruses with DNA genome
an antiviral agent that incorporates into viral DNA so cell RNA polymerase cannot “read” it
T/F: antiviral drugs that inhibit RNA polymerase that “read” RNA genomes will not block normal cell processes
TRUE
summarize the 3 steps viral mRNA is made into protein
- large mRNA translated to polyprotein
- polyprotein cleaved to functional proteins by viral protease
- generation of multiple mRNA and translation to individual proteins
antiviral agents, like current HIV drugs, inhibit what
viral protease
what are 2 antiviral agents for DNA polymerases
- nucleoside/nucleotide analog
- non-nucleoside revese transcriptase inhibitor
nucleoside analogs inhibit what
polymerase function
what 2 ways do nucleoside analogs inhibit polymerase function
- chain terminators
- polymerase inactivators
T/F: a nucleoside analog must undergo 3 phosphorylations to become active
TRUE
summarize chain terminators
- DNA polymerase inserts nucleoside in growing DNA chain and can’t accept any more nucleotides
- high affinity for viral polymerase
- low affinity for cell polymerase
summarize polymerase inactivators
- delivered as inactive drug
- bind viral polymerase better than cell polymerase
- active only in infected cells
what antiviral agents are used for retroviruses
- those that inhibit viral polymerase
- inhibit viral integrase
