Question

List important features of Watson & Crick model of DNA?

Answer 1

1. Watson and Crick discovered the well-known double helical structure of DNA, for which they received the Nobel Prize in 1962.
2. DNA is made up of two polynucleotide chains (strands) that are long, parallel, and spirally coiled around the same axis.
3. These chains form a double helical structure. The two strands are anti-parallel to each other. One stand runs in 5'-3' polarity and the other runs in 3' to 5' polarity.
4. The sugar and phosphate units form the backbone of the polynucleotide chains and the paired nitrogenous bases form the centre.
5. The nitrogenous bases of the two strands form hydrogen bonds according to their complementary, with Adenine forming two H-bonds with Thymine and Guanine forming three H-bonds with Cytosine.
6. The DNA has a diameter of 20nm and bases with a diameter of 0.34nm. The length of the turn is 3.4 nm and there are 10 base pairs per turn.
7. Phosphodiester bonds connect the nucleotides in a helix.
8. A minor groove and a major groove can be seen on the helix.