As discussed in question 11 above, viruses can contain RNA or DNA as their genet
ID: 91843 • Letter: A
Question
As discussed in question 11 above, viruses can contain RNA or DNA as their genetic material. Certain RNA viruses can exist as proviruses in which the viral genetic material has been inserted into the chromosomal DNA of the host cell. For this to happen, the viral RNA must be copied into a strand of DNA. An enzyme called reverse transcriptase, encoded by the viral genome, copies the viral RNA into a complementary strand of DNA. The strand of DNA is then used as a template to make a double-stranded DNA molecule. This double-stranded DNA molecule is then inserted into the chromosomal DNA, where it may exist as a provirus for a long period of time. a) How is the function of reverse transcriptase similar to the function of telomerase? b) Unlike DNA polymerase, reverse transcriptase docs not have a proofreading function. How might this affect the proliferation and evolution of the virus?Explanation / Answer
a. Telomerase enzyme is a ribonucleoprotein and it contains RNA and proteins.telomerase use its own RNA to synthesis new strand on the 3' parental strand, elongates in the 5'to 3' directions. Reverse transcriptase and telomerase have one thing in common that both use RNA as a template, though telomerase have a reserved sequence for template and found only in Eukaryotes.
b. Reverse transcriptase doesn't have a proof reading ability so when it synthesis DNA it has a high chance to incorporate little point mutation, and that point mutations leading towards variation in genetic material and finally leading towards antigenic variation by which a virus can easily bypass immune system and drugs which are specific for one type of antigen and outbreak occurs.
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