Question

Select the option with correct dimensions of A, B and C in the given below double helical structure of DNA proposed by Watson and Crick.

• A. $A \, - \, 3.4 \, nm, \, B \, - \, 0.34 \, nm, \, C \, -2nm$
• B. $A-34 \, nm, \, B-3.4 \, nm, \, C- \, 20 \, nm$
• C. $A-3.4 \, Å, \, B-034 \, Å. \, C-20 \, Å$
• D. $A \, - \, 34 \, Å, \, B-3.4 \, Å, \, C-2 \, Å$

Answer 1

Answer: (A)

The DNA helix makes one complete spiral turn every $3.4$ nm and has a diameter of $2$ nm. The distance between adjacent stacks is $0.34$ nm.