RNA-based viruses such as poliovirus use RNA as their genetic storage material. An important anti-viral drug is ribavirin (see below). RNA polymerase can use ribavirin (the triphosphate version) as a substrate, and it has been suggested that this leads to high mutation rates. With so many mutations to its genetic material, the virus can no longer survive and succumbs to ‘error catastrophe.

a. Give three (bio)chemical reasons why ‘modern' organisms (i.e. not viruses) use DNA for their genetic information storage material instead of RNA.

b. Why would ribavirin's ability to interact with both cytosine and uracil lead to high rates of genetic mutation?