Question

different types of viruses have different nucleic acids as their genetic material.for each type, trace the flow of information from their genetic material (i.e. +RNA, -RNA, etc) to a replicated viral genome and what route is taken for expression of viral genes. what is unique about retroviruses?

Answer 1

Viruses are different forms which consists of either DNA or RNA only. When the virus enters into the host cell it send its genetic information in the form of copy which get integrate into the host genome by the enzyme called integrase. This form is termed as prophage.

In case of RNA as genetic material, DNA intermediate is formed and get replicated. Viruses consists of only protein coat and nucleic acids so it uses host protein machinary for the production of new coat proteins. So the virus is totally dependent on the host cell for the replication of both nucleic acid in protein coat.

Retrovirus : in the case of retroviruses like HIV which consists of own polymerase along with nucleic acid which is called as reverse transcriptase. The enzyme reverse transcriptase converts RNA into complementary DNA cDNA and get integrated with host genome. The presence of this enzyme is an unique feature of retroviruses, as virus depends on host machinery for replication it is very difficult to develop drug targets against the viral pathogens.