Dna

These are the basic building blocks, each consisting of a sugar, a phosphate, and one of four nitrogenous bases.

The "sides" of the ladder are made of alternating sugar (deoxyribose) and phosphate groups. These are the basic building blocks, each consisting

The specific sequence of these four bases (A, T, C, and G) creates a biological alphabet that MedlinePlus Genetics compares to letters in a sentence. What is DNA?: MedlinePlus Genetics What is DNA

The National Human Genome Research Institute defines DNA as a , a shape resembling a twisted ladder. Molecular Structure The "rungs" are formed by pairs

DNA () is the hereditary molecule that carries the genetic "instruction manual" for the development, survival, and reproduction of nearly all living organisms . It functions as a stable repository of information, stored in every cell's nucleus, that dictates physical traits and biological functions. Molecular Structure

The "rungs" are formed by pairs of bases held together by hydrogen bonds. They follow strict pairing rules: Adenine (A) always pairs with Thymine (T) . Guanine (G) always pairs with Cytosine (C) . The Genetic Code