During the cell reproduction, DNA molecule is copied via the process of replication. During the DNA replication each strand of the original DNA molecule serves as a template for the production of new strand.
On the other hand, mRNA is a molecule which serves as a template for the protein synthesis in the process of translation. The genetic code within mRNA (set of nucleotide triplets) is decoded in a ribosome to produce a specific amino acid chain-polypeptide (future protein).
DNA and RNA differ in structure (DNA is double-stranded and contains deoxyribose sugar).
RNA converts the genetic information, which is within DNA, to a format used for protein synthesis.
