Question

How does the double helix model support the three major functions of genetic materials?

Answer 1

A DNA molecule consists of two long polynucleotide chains having anti-parallel polarity, composed of four types of nucleotide subunit which are linked covalently into a polynucleotide chain (a DNA strand) with a sugar-phosphate backbone from which the bases (A, C, G, and T) extend to the centre.

DNA is being the genetic material has the following functions in a cell:

1. Replication ( Ablility to generate its replica)

2. Gene expression ( ablility to express itself in the form of Mendelian Characters)

3. Mutation ( ability to undergo slow changes that are required for evolution)

The double helical model can explain the all functions of DNA as follows: ( Please refer the DNA double helical Structure)

Because of rule of complementarity, DNA has the ability to direct its duplications.

DNA can code for the synthesis of proteins by menas of transcription and translation processes by having the nucleotide sequence on it.

DNA is being more stable as it has 2'- deoxy ribose sugar in it's nucleotides. This sugar has 2'- H group which is chemically more stable and hence less reactive, is preferred for storage of genetic information.

DNA can be able to mutate as a change in single nucleotide can alter the gene expression. But being stable molecule as it is having deoxy ribose sugar this mutation rate is very slow which provides raw material for evolution.