THE MOLECULAR BASIS OF INHERITANCE
THE GENETICS OF VIRUSES AND BACTERIA
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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host cells rapidly destroy the viruses.
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these enzymes translate viral mRNA into proteins.
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host cells lack enzymes that can replicate the viral genome.
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these enzymes cannot be made in host cells.
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Detailed explanation-1: -These polymerases are not found in the host cells and are encoded by the viral genome. Thus, host cells lack the enzymes necessary to transcribe the RNA of viruses. Therefore, the given statement is true.
Detailed explanation-2: -RNA viruses require their own supply of certain enzymes because host cells lack enzymes that can replicate the viral genome.
Detailed explanation-3: -Replication occurs in the cytoplasm. The virus codes for its own RdRp, which converts the (−) stranded RNA into (+) RNA template strands. The (+) RNA serves two roles: (1) as the viral mRNA, which is then translated into viral gene products, and (2) as template to produce more (−) RNA strands.
Detailed explanation-4: -Viruses with dsDNA genomes therefore have the most similar nucleic acid to living organisms and often use the enzymes and proteins that the cell normally uses for DNA replication and transcription, including its DNA polymerases and RNA polymerases.
Detailed explanation-5: -For many (+)RNA viruses, RNA replication requires viral enzymes such as RdRp, helicase, capping enzymes, and NTPase, as well as non-enzymatic proteins that participate in the assembly of the viral replication complex. Host cell proteins often play essential roles in (+)RNA virus replication as well.