Thank you for reporting, we will resolve it shortly
Q.
If there are 135 hydrogen bonds between two strands of a fragment of DNA double helix, which contains 23 Guanine nitrogen bases. What is its total length?
EAMCETEAMCET 2010
Solution:
If the hydrogen bonds between two strands of a fragment of DNA double helix is 135, then hydrogen bonds between guanine and cytosine is $ \text{(}23\times 3\text{) }69 $ (as, GC pairs with three hydrogen bonds). $ \therefore $ The adenine nitrogen bases $ =69-135=66\div 2=33 $ The total nitrogen bases = 56 Distance between one $ bp=3,4{\AA} $ $ \therefore $ Total length $ =56\times 3.4=190.4\text{ }{\AA} $