DNA is a linear molecule composed of four types of smaller chemical molecules called nucleotide bases: adenine (A), cytosine (C), guanine (G), and thymine (T). The order of these bases is called the DNA sequence.

Where is DNA composed?

Most DNA is located in the cell nucleus (where it is called nuclear DNA), but a small amount of DNA can also be found in the mitochondria (where it is called mitochondrial DNA or mtDNA).

What is DNA and its structure?

DNA is made up of molecules called nucleotides. ... Nucleotides are attached together to form two long strands that spiral to create a structure called a double helix. If you think of the double-helix structure as a ladder, the phosphate and sugar molecules would be the sides, while the base pairs would be the rungs.