Question

Write a note on Watson and Crick DNA Model.

Answer 1

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✔James Watson and Francis Crick in 1953 proposed the Double Helix Model fir the structure of DNA.

● The salient features of the Double-Helix structure of DNA are:

⭐ It is made up of two polynucleotide chains where sugar-phosphate acts as a backbone.

⭐The two chains have anti-parallel polarity. If one chain has polarity 5'- 3', the other has 3'-5'.

⭐The bases of the two strands are held together by hydrogen bonds. Adenine forma two hydrogen bonds with Thymine and guanine is bonded with Cytosine with three H-bonds.

⭐The two chains are coiled in a right-handed fashion.

⭐ The plane of one base pair stacks over the other in double helix.

Answer 2

Explanation:

In Watson and Crick's model, the two strands of the DNA double helix are held together by hydrogen bonds between nitrogenous bases on opposite strands. Each pair of bases lies flat, forming a "rung" on the ladder of the DNA molecule. Base pairs aren't made up of just any combination of bases.