Chemistry of Life

Molecular genetics, biochemistry


Single chain (monomeric) nucleic acids are called nucleotides – each consists of a nitrogenous heterocyclic nucleobase (either a purine or a pyrimidine), a pentose sugar, and a phosphate group. Adenine and guanine are purines and cytosine, uracil, and thymine are pyrimidines.

Complementary base pairing involves a specific purine hydrogen bonded to a specific pyrimidine, thus: AT, AU & GC

ball-stick - dna double helix : animation - adenine tyrosine H bonds : animation - cytosine guanine H bonds : animation - start of transcription :

. . . transcription begun 10/06/06