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.
Helicases are enzymes that bind and may even remodel nucleic acid or nucleic acid protein complexes. There are DNA and RNA helicases. DNA helicases are essential during DNA replication because they separate double-stranded DNA into single strands allowing each strand to be copied.During DNA replication, DNA helicases unwind DNA at positions called origins where synthesis will be initiated.DNA helicase continues to unwind the DNA forming a structure called the replication fork, which is named for the forked appearance of the two strands of DNA as they are unzipped apart.here are DNA and RNA helicases. DNA helicases are essential during DNA replication because they separate double-stranded DNA into single strands allowing each strand to be copied. During DNA replication, DNA helicases unwind DNA at positions called origins where synthesis will be initiated.