NEET2022ZoologyMolecular Basis of InheritanceActual
If the length of a DNA molecule is 1 . 1 metres, what will be the approximate number of base pairs?
Options
- A6 . 6 × 10 9   bp
- B3 . 3 × 10 6   bp
- C6 . 6 × 10 6   bp
- D3 . 3 × 10 9   bp
Correct answer
D. 3 . 3 × 10 9   bp
Step-by-step solution
The two chains of DNA are coiled in a right-handed helicle fashion. The pitch of the helix is 3 . 4   nm and has a diameter of 2 nm. In the B-form of DNA, the distance between a bp in a helix is approximately 0 . 34   nm which means there are about 10 nucleotides present in a complete turn. The total length of DNA molecule in nm = 1 . 1 × 10 9 nm. The approximate number of base pairs = = 1 . 1 × 10 9 0 . 34 = 3 . 3 × 10 9