What Makes up the Backbone of the DNA Molecule?

up-backbone-dna-molecule Credit: Liam Norris/Cultura/Getty Images

Two components make the backbone in DNA, being the deoxy-ribose and phosphate molecules. These molecules link together in a staggered pattern where the deoxy-ribose and phosphate molecules follow one another, like the backbone of a zipper. Deoxy-ribose is a type of sugar molecule where the adenine, guanine, cytosine and thymine molecules attach a covalent bond. The phosphate molecules bond with the deoxy-ribose molecule acting like anchors in DNA.

The structure of a deoxy-ribose molecule is five carbon atoms in a ring with oxygen atoms or oxygen and hydrogen molecules attaching themselves to the carbon. Deoxy-ribose has one fewer oxygen atom than ribose, which is one of the differences between DNA and RNA. Phosphorus and oxygen atoms with oxygen and hydrogen molecules comprise the elements of a phosphate molecule in DNA. Carbon, hydrogen, oxygen and phosphorus in the right amount and combination is all it takes for nature to create a backbone for DNA.

Science explains the way deoxy-ribose and phosphorous molecules stay together as the 3- and 5-prime phosphodiester linkage. This is simply a way of keeping track of the phosphate and deoxy-ribose molecules where 5 ends a phosphate and 3 ends a deoxy-ribose molecule. This linkage is true in all DNA molecules.