Nucleic acids are organic molecules that contain genetic information and play a vital role in various biological processes. They consist of two main types - DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). Both DNA and RNA are composed of nucleotides, which are the building blocks of these acids. Nucleotides contain a sugar molecule, a phosphate group, and one of four nitrogenous bases - adenine, guanine, cytosine or thymine in DNA, while RNA contains uracil instead of thymine. These nucleic acids are responsible for storing, transmitting and expressing genetic information from generation to generation through processes such as replication, transcription and translation. They play a crucial role in cellular metabolism, growth, development, and reproduction.