Question

Length of one turn of B-DNA helix is

• A. 20 nm
• B. 3.4 nm
• C. 10 nm
• D. 0.34 nm

Answer 1

The correct option is B 3.4 nm

The DNA duplex model proposed by Watson and Crick is a right-handed spiral and is called B-DNA.

Each turn (coil) of the helix is called a pitch and has a length of around 34A°.

Since, 1 nm = 10 Angstrom.

Therefore, 34 Angstrom is same as 3.4 nm