Definition: In biology, double helix is a term used to describe the structure of DNA. The shape is similar to that of spiral staircase. DNA is a nucleic acid composed of nitrogenous bases (adenine, cytosine, guanine and thymine), a five-carbon sugar (deoxyribose), and a phosphate molecule. The nucleotide bases of DNA represent the stair steps of the staircase and the deoxyribose and phosphate molecules form the sides of the staircase.
Examples: DNA Models
