stars and stripes 2 italics the national anthem of the united states of america based on a poem written by francis scott key on september 14 1814 and set by him to the melody of the english song to anacreon in heaven officially adopted by the u s congress in 1931 examples from the web for star spangled banner expand
The two strands of DNA are held together by weak hydrogen bonds (remember, something must hold them together!) between the nitrogenous bases. The interesting (and very important) aspect of the Watson-Crick model is that these hydrogen bonds are base specific.
Nucleotides that form the strands of the DNA structure are complex molecules which consist of both a phosphate moiety and a nucleobase (adenine, guanine, cytosine or thymine) joined to a five-carbon sugar (deoxyribose). In RNA, the five-carbon sugar ribose replaces deoxyribose.