BIOL 201 Lecture Notes - Friedrich Miescher, Francis Crick, Nucleobase
Document Summary
Dna is a molecule encoding thegenetic instructions used in the development and functioning of all known living organisms and many viruses. Along with rnaand proteins, dna is one of the three major macromoleculesthat are essential for all known forms of life. Dna is well-suited for biological information storage, since the dna backbone is resistant to cleavage and the double-stranded structure provides the molecule with a built-in duplicate of the encoded information. These two strands run in opposite directions to each other and are therefore anti-parallel, one backbone being 3" (three prime) and the other 5" (five prime). This refers to the direction the 3rd and 5th carbon on the sugar molecule is facing. Attached to each sugar is one of four types of molecules callednucleobases (informally, bases). It is the sequence of these four nucleobases along the backbone that encodes information. This information is read using the genetic code, which specifies the sequence of the amino acids within proteins.