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The RNA world is a hypothetical stage in the evolutionary history of life on Earth in which self-replicating RNA molecules proliferated before the evolution of DNA and proteins. [1] The term also refers to the hypothesis that posits the existence of this stage. Alexander Rich first proposed the concept of the RNA world in 1962, [2] and Walter ...
The transition from non-life to life has never been observed experimentally, but many proposals have been made for different stages of the process. The study of abiogenesis aims to determine how pre-life chemical reactions gave rise to life under conditions strikingly different from those on Earth today.
Central dogma of molecular biology. The central dogma of molecular biology deals with the flow of genetic information within a biological system. It is often stated as "DNA makes RNA, and RNA makes protein", [1] although this is not its original meaning. It was first stated by Francis Crick in 1957, [2][3] then published in 1958: [4][5]
Ribonucleic acid (RNA) is a polymeric molecule that is essential for most biological functions, either by performing the function itself (non-coding RNA) or by forming a template for the production of proteins (messenger RNA). RNA and deoxyribonucleic acid (DNA) are nucleic acids. The nucleic acids constitute one of the four major ...
RNA-based evolution. RNA-based evolution is a theory that posits that RNA is not merely an intermediate between Watson and Crick model of the DNA molecule and proteins, but rather a far more dynamic and independent role-player in determining phenotype. By regulating the transcription in DNA sequences, the stability of RNA, and the capability of ...
The sequence of nucleobases on a nucleic acid strand is translated by cell machinery into a sequence of amino acids making up a protein strand. Each group of three bases, called a codon, corresponds to a single amino acid, and there is a specific genetic code by which each possible combination of three bases corresponds to a specific amino acid.
The Nirenberg and Leder experiment was a scientific experiment performed in 1964 by Marshall W. Nirenberg and Philip Leder. The experiment elucidated the triplet nature of the genetic code and allowed the remaining ambiguous codons in the genetic code to be deciphered. In this experiment, using a ribosome binding assay called the triplet ...
Pre-cell. The terms pre-cell (precell), proto-cell (protocell), etc. are frequently used to designate hypothetical ancestral entities precursing complete cells. The meanings of these terms vary with the different hypotheses for the early evolution of life and, accordingly, with the corresponding publications.