Lecture 17.3: HIV replication and reverse transcriptase inhibitors

Question 1

viral RNA is terminally __

Answer 1

redundant

Question 2

+ssrna is converted to dsrna using the enzyme __

Answer 2

reverse transcriptase

Question 3

reverse transcriptase makes the groups flanking the R on the 5’ and 3’ ends ___. what does this help in?

Answer 3

identical. influences integration into host RNA

Question 4

zidovudine is an analog for __

Answer 4

thymidine

Question 5

Zidovudine is phosphorylated and incorporated into the growing chain as a ___

Answer 5

chain terminator

Question 6

zidovudine doesn’t have a 3’ OH group, but instead has a __ group that is very ___ and not __

Answer 6

N3; reactive; not useful for DNA replication

Question 7

why doesn’t zidovudine block host DNA polymerase?

Answer 7

it does, but it has 100x more affinity for HIV reverse transcriptase

Question 8

what are the consequences of zidovudine inhibition of host DNA polymerase?

Answer 8

toxicity to host by blocking host DNA replication

Question 9

reverse transcriptase is prone to __

Answer 9

errors

Question 10

there is at least __ mistakes every time the HIV genome is reverse transcribed

Answer 10

1

Question 11

a mistake by reverse transcriptase leads to development of ___

Answer 11

viral quasi species

Question 12

what are viral quasi species?

Answer 12

closely related mutant viral genomes subjected to continuous genetic variation, competition and selection

Question 13

what is the result of viral quasi species?

Answer 13

diverse population of viruses

Question 14

quasi species are the major force behind what 3 things ?

Answer 14

1. quick evolution of HIV
2. development of resistance to drug regimens
3. failure of vaccine trials