Question

DNA is considered a more stable genetic material than RNA. Justify this statement with suitable reasons.

Hint:

DNA lacks the reactive 2-OH of ribose, is double stranded and has thymine, so it is more stable.

Answer 1

Step 1: Understanding the Concept:
A genetic material must store information for a long time, so it must be chemically stable. It must also be able to copy itself.
DNA and RNA differ in their sugar, their bases and their strands. These differences decide how stable they are.

Step 2: Reason 1: the sugar:
RNA has ribose, which carries a free \( 2^{\prime} \)-OH group. This group is reactive and makes the RNA chain easy to break (labile).
DNA has deoxyribose, which has no \( 2^{\prime} \)-OH group. So DNA is chemically less reactive and more stable.

Step 3: Reason 2: the strands and bases:
DNA is double stranded. The bases are paired and kept inside the helix, so they are protected. It also has a proofreading and repair system.
RNA is usually single stranded and its bases are exposed. DNA has thymine in place of uracil, which helps the cell spot and repair damage to cytosine.

Step 4: Conclusion:
For these reasons DNA is the genetic material in most organisms. RNA is better suited for short-lived jobs such as messenger and adaptor roles.

Final Answer:
DNA is more stable than RNA because it has no \( 2^{\prime} \)-OH group on its sugar and because it is double stranded with thymine and a repair system.