DNA, or deoxyribonucleic acid, is a molecule that carries the genetic instructions for the development, functioning, growth, and reproduction of all known living organisms and many viruses. It is often referred to as the “building block of life.”
DNA is composed of two long chains made up of nucleotides, which are molecules consisting of a sugar (deoxyribose), a phosphate group, and one of four nitrogenous bases: adenine (A), guanine (G), cytosine (C), and thymine (T). The nucleotides on each chain are connected by bonds between the sugar of one nucleotide and the phosphate group of the next, forming a backbone.
The two chains of DNA twist around each other to form a double helix structure, held together by hydrogen bonds between the nitrogenous bases. The sequence of these bases along the DNA strands encodes the genetic information.
The arrangement of the nitrogenous bases determines the genetic code, which specifies the sequence of amino acids in proteins. Proteins are essential molecules that perform a wide range of functions in living organisms, including enzymes that catalyze biochemical reactions, structural components of cells and tissues, and signaling molecules that regulate cellular processes.
Through processes like DNA replication, transcription, and translation, the genetic information encoded in DNA is used to produce proteins and control various cellular activities, ultimately determining the characteristics and traits of an organism. DNA is passed from parent to offspring during reproduction, ensuring the inheritance of genetic traits across generations.