Question

The length of one turn of the helix in B-form DNA is approximately

• A. 0.34 nm
• B. 20 nm
• C. 2nm
• D. 3.4 nm

Answer 1

Answer: (D)

3.4 nm

Answer 2

B-form of DNA shows right-handed coiling which contains $10$ base pairs in each turn. On complete turn, DNA occupies $34$ A distance. So in nm, it will $3.4 \,nm$ because or. $1 n m=10^{-9} \,m$ $1\,??10^{10}\, m$ So $34\,??=34\, x\, 10^{10} \,m$ $=3.4 \,nm$