Question

Diameter of DNA is/Wilkin's X-ray diffraction showed DNA diameter to be

• A. $200\mathring{A}$
• B. $100\mathring{A}$
• C. $20\mathring{A}$
• D. $50\mathring{A}$

Answer 1

Answer: (C)

$20\mathring{A}$

DNA has the double helical structure where the two strands are tightly coiled over each other. B- DNA has right-handed helix with the major and minor groove. The diameter of the DNA is 20 A${}^o$. The number of base pairs in one turn is 10 and the distance between base pairs is 3.4 A${}^o$. The total length of one turn of DNA is 34 A${}^o$.

So, the correct answer is option C.