a sugar molecule, and a phosphate group. Levene made his initial proposal in 1919, discrediting other suggestions that had been put forth about the structure of nucleic acids. In Levene's own ...

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 ...