Final answer:
The backbone of a DNA strand is composed of the sugar deoxyribose and phosphate, linked together by phosphodiester bonds to form the sugar-phosphate backbone.
Step-by-step explanation:
The backbone of one DNA strand consists of the sugar deoxyribose and phosphate which are linked together by phosphodiester bonds. In DNA, sugar-phosphate groups line up to form a sugar-phosphate backbone for each single strand, while the nucleotide bases, which include adenine, thymine, guanine, and cytosine, stick out from this backbone. The phosphate group of one nucleotide bonds covalently with the 5' carbon of one sugar molecule and the hydroxyl (OH) group on the 3' carbon of the next sugar molecule, thereby creating this contiguous backbone structure. The integrity of the DNA double helix is maintained by hydrogen bonds that form between complementary base pairs on opposing DNA strands.