Question

Ivy Louises CIUSSI15L VIULZJUSA EN VE2002A Wirei 2020 Moterm 2 COVID 19 is a + RNA virus with an unusually large genome (for a virus, ~30 Kbp). Like many RNA viruses, COVID19 has its own RNA polymerase, but a distinction between COVID19 and other RNA viruses is that its RNA polymerase has editing capacity. Predict the effect this may have on mutation rates in the viral genome. Explain how you have come to your answer. (4 marks) 1 in BIO = = g Finis Time MacBook Air 000 F

Answer 1

RNA polymerase is an enzyme that catalyzes the replication of RNA from an RNA template. It catalyses synthesis of the RNA strand complementary to a given RNA template. Virus has mutation that makes it particularly deadly to its human host and kills the host within a few hours of infection. The virus needs a new, healthy host for its descendents to survive.

A virus that appears different from other viruses that have infected the host has an advantage the host has no pre-existing immunity, in the form of antibodies, to that virus. Many viral adaptations involve changes to the virus’s outer surface.

RNA viruses, meaning that their genetic material is encoded in RNA, not DNA. DNA is a more stable molecule than RNA, and DNA viruses have a proofreading (editing) check as part of their reproductive process. They manage to use the host cell to verify viral DNA replication.

If the virus makes a mistake in copying the DNA, the host cell can often correct the mistake. DNA viruses, therefore, do not change, or mutate much. RNA, however, is an unstable molecule, and RNA viruses don’t have a built-in proofreading step in their replication. Mistakes in copying RNA happen frequently, and the host cell does not correct these mistakes. RNA virus mutations are frequent and can have important consequences for their hosts.

But in the case of Covid-19 its ability to edit the sequence make it different from other virus. This ability make the correct replication of RNA with correct base sequences. This ability of editing of Covid -19 make them more stable like DNA virus in host cell.