In the double helix model of DNA , how far is each base pair from the next base pair

Options

A. 3.4 nm
B. 0.34 nm
C. 20 nm
D. 34 nm

Answer

B

Explanation

The two chains are coiled in a right-handed fashion. The pitch of the helix is 3.4 nm (a nanometer is one billionth of a meter, that is `10^(-9)` m) and there are roughly 10 bp in each turn. Consequently, the distance between a bp in a helix is approximately equal to 0.34 nm.