BIOLOGICAL CLASSIFICATION
VIRUSES
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Why do RNA viruses tend to have unusually high rates of mutation?
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RNA viruses can incorporate a variety of nonstandard bases.
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Replication of their genomes does not involve proofreading.
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RNA viruses replicate faster.
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RNA nucleotides are more unstable than DNA nucleotides.
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Explanation:
Detailed explanation-1: -The higher per-site mutation rates of RNA viruses can be explained in part by the RNA-dependent RNA polymerases (RdRp) that replicate their genomes. Unlike many DNA polymerases, RdRp do not have proofreading activity and are thus unable to correct mistakes during replication.
Detailed explanation-2: -First, the polymerases of the vast majority of RNA viruses lack 3′ exonuclease proofreading activity and hence are more error-prone than those of DNA viruses [9, 10].
Detailed explanation-3: -RNA viruses tend to have an unusually high rate of mutation because their RNA genomes cannot be corrected by proofreading.
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