What forms the "backbone" of a nucleic acid?
A) purine and pyrimidine pairs, hydrogen- bonded to each other
B) a chain of sugar and phosphate groups, linked through phosphodiester bonds
C) a double helix of antiparallel strands
D) a chain of amino and carboxyl groups, linked via peptide bonds

Question

Quizplus · Accepted Answer

The backbone of a nucleic acid is composed of a chain of sugar and phosphate groups, linked through phosphodiester bonds. Purines and pyrimidines pair up to form the rungs of the ladder-like, double-stranded structure of DNA, but they do not form the backbone itself. Amino and carboxyl groups linked via peptide bonds form the backbone of proteins, not nucleic acids. While a double helix of antiparallel strands describes the structure of DNA, it is not the backbone itself.

What Forms the "Backbone" of a Nucleic Acid