Later it was found that the sugar in nucleic acid can be ribose ... Scientists still needed to figure out this molecule's structure to be sure, and to understand how it worked.

(It takes two bases to form a rung -- one for each side of the ladder.) A sugar molecule, a base, and a phosphate molecule group together to make up a nucleotide. Nucleotides are abundant in the ...

In 1953, Francis Crick and James Watson first described the molecular structure of DNA ... backbones of the double helix are made up of sugar and phosphate molecules that are connected by chemical ...