DNA is a double-helix - it looks like a twisted ladder. Its backbone is made of sugars (deoxyribose) and phosphate groups, and the rungs of the ladder are made from 4 nitrogenous bases: Guanine, Adenine, Thymine, and Cytosine. The order of the “rungs,” or bases, is what determines what the DNA is coding for. Think of it like the order of letters in a word, and the order of words in a sentence. Except in the language of DNA, there are only 4 letters. In this video, we discuss the structure of DNA - how big is it, how are the components attached to each other, and what is the spacing between the rungs. We’ll also learn about the major groove and minor groove, and other important details about DNA structure.