Question

Examine the differences between DNA and RNA. Explain why DNA is the most favorable molecule for genetic material and how RNA compares to it in this respect.

Answer 1

1. DNA is a double helix, with two chains bonded together and twisted, and RNA is a single helical molecule,with only one chain twisted.
2. DNA has the base Thymine (T) but not Uracil (U); RNA has U but not T.
3.& DNA contains the pentose sugar deoxyribose; RNA contains the pentose sugar ribose.
RNA molecules are very unstable. One of the causes is that its ribose has hydroxy group (OH-) at the 2'-position, at which different chemical oxidizing agents can be added. It is a risk for genetic information which has to be stored very carefully. That is why DNA is more suitable. Moreover, availability of 2 chains in DNA allows to repair information based on the complementarity rule.