what makes up the sides of the dna molecule?

The sides of the DNA molecule, often described as the "backbone" of the DNA ladder, are made up of alternating sugar and phosphate groups. Specifically, the sugar in DNA is deoxyribose, a five-carbon sugar, and these sugar molecules are connected to each other by phosphate groups forming phosphodiester bonds. This sugar-phosphate backbone provides the structural framework for the DNA strand, with the nitrogenous bases (adenine, thymine, cytosine, and guanine) attached to the sugars forming the rungs of the ladder. The two DNA strands run in opposite directions (antiparallel) and twist into a double helix shape.