The answer is E.
This Q is simply asking about a very high yield concept. Which one is +ve RNA virus?
Actinomycin D acts in the nucleus. So every thing in the nucleus, whether mammalian or viral is shut off, as the Q stem is clearly saying.
+ RNA is exactly the same as mRNA. It can be translated directly in the cytoplasm by ribosomes. One of the translated proteins is a Polymerase that first transcribes it into -ve strand, then transcribes that -ve stand into +ve stands for more progeny.
For those who answered B, We are not talking about whether AIDS is curable or not. It goes on in experimental culture cells. Besides, HIV virus makes a double stranded DNA that integrates into host DNA and uses his machinery.
@Mondoshawan, I also chose D. What was in my mind that Most RNA viruses replicate in the cytoplasm and -ve RNA virus have their own polymerase, but their are exceptions. Their are only two RNA viruses that replicate in the nucleus, ortho (influenza) and retro. This is what makes D wrong.
Here are two more Qs that test the same concept.
A virus is isolated in the laboratory. Electron microscopy shows that new virions assemble in the cytosol and are released by cell lysis. Virions lack envelopes and are approximately the size of Hepatitis A virions. The genome is single-stranded and replicates in the cytoplasm; no dependence on nuclear functions can be demonstrated. When genomes purified from virions are added to cultured cells, a small amount of progeny virus is produced. Based on these data, what is the most likely nature of the viral genome?
A. DNA of (+) polarity.
B. DNA of (-) polarity.
C. RNA of (+) polarity.
D. RNA of (-) polarity.
A patient develops diarrhea produced by a previously-unknown virus. Electron microscopy shows that the virus replicates in the cytoplasm and lacks an envelope. Virions are small, approximately the size of Polio virions, and contain single-stranded genomes. When nucleic acid purified from virions is added to cultured cells, a small amount of progeny virus is produced. Based on these data, what is the most likely nature of the viral genome?
A. Single-stranded DNA of (+) polarity.
B. Single-stranded DNA of (-) polarity.
C. Single-stranded RNA of (+) polarity.
D. Single-stranded RNA of (-) polarity.
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