EK Bio 49

[pgoyal]

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Which of the following events does NOT play a role in the life cycle of a typical retrovirus?

a. viral dna is injected into the host cell
b. viral dna is integrated into the host genome.
c. the gene for RT is transcribed and the mRNA is translated inside the host cell
d. viral DNA incorporated into the host genome may be replicated along with the host dna.

earlier in the book it says:

"...retroviruses such as the virus that causes AIDS. A retrovirus carries the enzyme RT in order to create DNA from its RNA. the DNA is then incorporated into the genome of the host cell"

okay so B & D is obviously eliminated.

I picked C but the answer is A. i'm guessing that the virus only begins RTing it's RNA once the RNA & the RT is inside the host cell?

 

[Hemorrage]

I picked A, my reasoning was that the life cycle of a retrovirus doesn't really "start" until its incorporated into the host genome (Post reverse transcription, etc).

 

[Laureatebarrel]

Remember retrovirus has RNA not DNA (that's why it needs reverse transcriptase to make DNA), so when injected it is RNA not DNA. C is right and A is wrong (A is the choice here).