Why all living organisms need to have DNA?

Answer 1

DNA and RNA give the instructions to the body on how to make all of the protein molecules that build and regulate our body functions. Using the blueprint provided in our DNA and RNA, each of these vital molecules are made identically each time they are needed. Furthermore, our genetic traits are contained in our DNA, allowing us to pass on those traits to our children and grandchildren. The continuity the human species is contained in our DNA.

Answer 2

Basically, DNA stores the information about the characteristics of a living being, and RNA transfers this information, to make the corresponding proteins - each gene (a small part of DNA) encodes a protein sequence, and RNA transfers these instructions. It is more complicated, though; if I remember correctly, there are several types of RNA with different functions - better read some articles, for additional information.

Answer 3

We haven't found any living organisms that do not contain DNA. That doesn't necessarily mean that DNA is required. It is possible to construct analogues of DNA that are not actually DNA: RNA, for example, is a pretty good match and theoretically could be used as a basis for life (in fact, many biologists believe that the earliest lifeforms on Earth used RNA exclusively and that DNA was a later development).

Answer 4

DNA has the code to make proteins but it can't send that code to the site where the proteins are made (ribosomes) without RNA.