DNA- Double Helix of Paired Bases
A DNA molecule has two strands joined together in a shape of a double helix. These two strands are held together by four bases: Adenine & Thymine, and Cytosine and Guanine.They are held together by weak hydrogen bonds.
A gene is a section of DNA and the sequence of the bases present, code for a specific protein to be made.
Rosalind Franklin and Maurice Wilkins discovered DNA had a helical structure by directing beams of X-rays into pure, crytillized DNA and looking at the patterns that the X- rays formed as they bounced off.
James Watson and Francis Crick used Franklin & Wilkins' ideas and produced a 3D model of the DNA, along with the knowledge of that the amount of Thymine & Adenine matched the amount of Cytosine and Guanine.