What distinguishes restriction endonucleases from other nucleases?

Restriction endonucleases are unique because they recognize and cleave specific short sequences of DNA, typically palindromic sequences. This specificity is crucial for many molecular biology applications, such as cloning, genetic engineering, and DNA analysis. The ability to target particular DNA sequences allows for precise manipulation of genetic material, which is fundamental in various research and therapeutic contexts.

Other nucleases, in contrast, may not exhibit such specificity and can act on a broader range of nucleic acids without recognizing specific sequences. For instance, some nucleases might degrade nucleic acids randomly, which would not be functional in applications that require precision, such as the creation of recombinant DNA.

The other options provided do not accurately describe the defining characteristics of restriction endonucleases. Some nucleases do require ATP for activity, but this is not a distinguishing feature of restriction endonucleases. Additionally, while some proteins can add methyl groups to nucleotides, this describes methyltransferases rather than nucleases. Finally, the option regarding the digestion of RNA molecules does not apply to restriction endonucleases since they primarily act on DNA, not RNA.