Biological Functions of Nucleic Acids:- The two important functions of nucleic acids are:

1. Replication
2. Synthesis of Protein

1. Replication:- Replication is the process by which a single DNA molecule produces two identical copies of itself. It is also called cell division and is an enzyme catalysed process. DNA has this unique property of replication. Each daughter cell has DNA molecule identical to that of the parent cell. The two strands of DNA molecule unwind and serve as temple of pattern for the synthesis of new strand.

2. Synthesis of Protein:- DNA act as instruction manual for the synthesis of all the proteins present in the cell. The genetic information is coded in DNA in the form of specific sequence of bases. The synthesis of a specific protein involves the following two steps:

(a) Transcription              (b) Translation

(a) Transcription:- A single strand of DNA can act as a template on which a molecule of RNA is synthesized in specific manner, this process is known as transcription. There are three type of RNA-messenger RNA (mRNA), transfer RNA (tRNA) and ribosomal (RNA (rRNA).

(b) Translation:- The RNA molecule formed in the process of Transcription directs the synthesis of a specific protein which are characteristic of each kind of organism. This process is called Translation.

In molecule biology, the word transcription is used as synonym for RNA synthesis and translation as a synonym for protein synthesis. It is represented by a diagram as