Answer to Question #23418 in Biochemistry for cathleen anderson

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.