DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are the nucleic acids that store and transmit genetic information in living organisms.
- DNA is a double helix; its structure was described by James Watson and Francis Crick in 1953, using X-ray data from Rosalind Franklin.
- DNA bases are adenine (A), thymine (T), guanine (G), and cytosine (C); pairing is A with T and G with C. In RNA, thymine is replaced by uracil (U).
- DNA carries the hereditary code in genes and is found mainly in the nucleus; RNA is usually single-stranded and helps make proteins.
- The central dogma of molecular biology: DNA is transcribed into RNA, which is translated into protein.
- Applications: DNA fingerprinting is used in forensics and crime investigation, and the structure underlies genetic engineering and recombinant DNA technology.
The structure of DNA, the base pairing, the Watson and Crick discovery, and DNA fingerprinting (forensics) are common biotechnology and genetics facts, with a clear policing link.
DNA versus RNA: DNA is double-stranded with thymine; RNA is single-stranded with uracil. A gene is a segment of DNA, while a chromosome is a packaged DNA-protein structure.
DNA is the double-helix genetic code (A-T, G-C); RNA is single-stranded with uracil and makes proteins.