What is the difference between saturated and unsaturated fatty acids, DNA and RNA, and purine and pyrimidine?

The difference between saturated and unsaturated fatty acids lies in the chain links. The saturated ones have simple bonds and are more solid, the unsaturated ones, they have double ligature and that generates their fluidity.

DNA and RNA, are both nucleic acids but their difference lies in the monosaccharide that compose them: the DNA has the pentose of the deoxyribose type while the RNA has the pentose of the ribose type.

Purines and pyrimidines differ in the chemical composition of each, while purine has double rings fused, pyrimidine has a single ring (heterocyclic). The two classify the nitrogen bases of DNA and RNA, with adenine and guanine being derived from purine and derived from pyrimidine, cytosine, thymidine and uracil.