describe a DNA molecule as two strands coiled to form a double helix, the strands being linked by a series of paired bases: adenine (A) with thymine (T) and cystosine (C) with guanine (G).
If we look at a section of the double helix we will see bases that are close together and there are four different types of bases: adenine (A) with thymine (T) and cystosine (C) with guanine (G). In the molecule the bases are what holds the double helix together. And they are held together by pairing between adenine -thymine and guanine -cystosine. These are known as the base pairs.
If we look on one side of helix you will see the sequence of A,C,T,G,A,A,C,C,A,G. This is the 'order of the vase' => and its this order that we call the GENE.
Gene can be defined as the order of the bases and the number of the bases. This is for the construction of the protein in the cytoplasm which gives us the characteristic.