Q. One turn of the helix in a B-form DNA is approximately
A) 2 nm
B) 20 nm
C) 0.34 nm
D) 3.4 nm.
Explanation
DNA or deoxyribonucleic acid is the largest macromolecule made of the helically twisted two antiparallel polydeoxyribonucleotide strands held together by hydrogen bonds. The two strands of DNA are together called DNA duplex. It has a diameter of 20Å. One turn spiral has a distance of 34Å or 3.4 nm.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.