Single stranded of RNA polymers are relatively quickly digested by enzymes called ribonucleases unless they posses much intrastand base pairing or unless they are extensively complexed with proteins such as those in ribosomes.
Why DNA is more stable than RNA?
- DNA molecules are much more stable because they are double stranded throughout their length and enzymes are normally present in the nucleus to repair damage to DNA.
- There are no comparable enzymes either in the nucleus or in the cytoplasm to repair RNA damage
- RNA molecules must be continuously replaced as they are being broken down at various rates.
- The presence of OH group in the 3rd position makes RNA less stable compared to DNA and is more reactive and more succeptable to hydrolysis.