Which of the following parts of a DNA molecule are held together by hydrogen bonds?

a) the carbons within the sugar-phosphate group
b) the carbons within the nitrogen-containing bases
c) nucleotide bases on opposite strands of the double helix
d) successive nucleotides within a single strand of the double helix
e) all of the above


Ans: c) nucleotide bases on opposite strands of the double helix
Sugar and phosphate are attached to each other by phosphate ester Bond which is a covalent bond.
Sugar and nitrogenous bases are attached to each other by n glycosidic Bond which is a covalent bond.
Nitrogenous bases on the opposite trans are connected to each other by hydrogen bond. This is the bond which keeps to two strands together in a double helix.
Adjacent nucleotides in a single strand are connected to each other by phosphodiester Bond which is also a covalent bond.

Biology & Microbiology

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