DNA

DNA, or deoxyribonucleic acid, is the molecule that carries the genetic instructions for all living organisms. It consists of two long strands twisted into a double helix, resembling a spiral staircase. Each strand is made up of smaller units called nucleotides, which contain a sugar, a phosphate group, and a nitrogenous base. The sequence of these bases encodes the information needed for building proteins, which perform various functions in the body. DNA determines traits and characteristics, and it is inherited from parents, making it essential for understanding genetics and biological inheritance.