Question

Calculate the number of phosphodiester, and glycosidic bonds in 100 base pairs long double-stranded DNA.

Answer 1

Phosphodiester bond: This bond is formed between, a 3' carbon atom of one sugar and a 5' carbon atom of another sugar molecule. It involves two sugar and one phosphate group that links both of them.

1. ​If the number of base pairs in a DNA is n, then the number of phosphodiester bonds will be 2x(n-1), now according to the formula, the number of phosphodiester bonds will be 2(100-1) = 198.
2. So the total no. of phosphodiester bonds in 100 base pairs is 198.

Glycosidic bond: This bond is formed between a nitrogen base and deoxyribose sugar in DNA.

1. The number of glycosidic bonds = 2 x the number of bases in dsDNA.
2. 2 x 100 = 200.