DNA, or deoxyribonucleic acid, is a molecule that carries the genetic instructions for life. It is composed of three major functional units:
- Deoxyribose Sugar: This is a five-carbon sugar that forms the backbone of the DNA molecule. It connects to the phosphate group on one side and the nitrogenous base on the other side, creating the structural framework of the DNA.
- Phosphate Group: The phosphate group is attached to the deoxyribose sugar and links to adjacent sugars, forming a chain. This connection creates the sugar-phosphate backbone, which is essential for the stability and structure of the DNA helix.
- Nitrogenous Bases: There are four types of nitrogenous bases in DNA: adenine (A), thymine (T), cytosine (C), and guanine (G). These bases pair specifically (A with T and C with G) to form the rungs of the DNA ladder, holding the two strands together through hydrogen bonds. The sequence of these bases encodes the genetic information.
Together, these three units create the structure and functionality essential for storing and transmitting genetic information in all living organisms.