If the distance between two consecutive base pairs is 0.34 nm and the total number of base pairs of a DNA double helix in a typical mammalian cell is 6.6×10^9 bp, then the length of the DNA is approximately :

1. 2.0 meters

2. 2.5 meters

3. 2.2 meters

4. 2.7 meters

Doubtly Asked 30 Oct 2026 NEET UG 2020 Practice test neet Save WhatsApp Report

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Answer: 3. 2.2 meters

Length = number of bp x distance per bp.

$$L = 6.6\times10^{9}\times0.34\times10^{-9}\ \mathrm{m} = 2.244\ \mathrm{m}\approx 2.2\ \mathrm{m}$$

So the answer is about 2.2 metres, option 3.

Doubtly AI · 30 Oct 2026 AI-generated · not yet verified Report

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