Question

If the distance between two consecutive base pairs is $0.34\text{nm}$ and the total number of base pairs of a DNA double helix in a typical mammalian cell is $6.6\times {10}^9\text{bp}$, then the length of the DNA is approximately -

• A. $2.2\text{meters}$
• B. $2.5\text{meters}$
• C. $2.7\text{meters}$
• D. $2.0\text{meters}$

Answer 1

The correct option is A $2.2\text{meters}$

The diploid content of human genome is $6.6\times {10}^9$ base pairs. The distance between two consecutive base pairs is $0.34\text{nm}(0.34\times {10}^{–9}\text{m})$, so the length of DNA double helix in a typical mammalian cell is around $6.6\times {10}^{–9}\text{bp}\times 0.34\times 10{}^{–9}\text{m/bp}=2.2\text{metres}$.
Hence, the correct answer is $2.2\text{metres}$