DNA molecule used to carry genetic information from one generation to the other; The basic unit of DNA is a nucleotide. Sugar found in the DNA is called deoxyribose. A phosphate group of one nucleotide interacts with the hydroxyl group of the other nucleotide to form a phosphodiester bond. However, this is not the only type of bond found in the DNA molecule. Nitrogenous bases are attached to the sugar on one chain and may interact with the nitrogenous bases attached to the sugar on the other chain. The principle of this interaction is described as the complementarity rule, where Adenine can bind to Thymine while Guanine binds to Cytosine. DNA replication always proceeds in one direction.
DNA replication is initiated at a DNA sequence called the promoter. The first enzyme that binds to this area of the DNA is called primase. This enzyme unwinds the DNA helix and allows short RNA sequences called DNA primers to bind to both DNA strands. The enzyme responsible for the extension of these short RNA sequences is called DNA polymerase.
Transcription results in the formation of RNA molecules and uses DNA as a template. The enzyme catalyzing this process is called RNA polymerase. Protein molecules are made through a process called translation. This process involves tRNA, mRNA, amino acids, and regulatory RNA.