The two polynucleotide chains in a DNA molecule are attached to each other by
A) hydrogen bonds between bases.
B) ionic bonds between ʺRʺ groups in amino acids.
C) peptide bonds between amino acids.
D) covalent bonds between phosphates and sugars.
E) covalent bonds between carbon atoms.

Question

Quizplus · Accepted Answer

The two polynucleotide chains in a DNA molecule are held together by hydrogen bonds between the nitrogenous bases (adenine pairs with thymine via two hydrogen bonds, and cytosine pairs with guanine via three hydrogen bonds). This is a key feature of the DNA double helix structure.

The Two Polynucleotide Chains in a DNA Molecule Are Attached