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The RNA world hypothesis places RNA at center-stage when life originated. The RNA world hypothesis is supported by the observations that ribosomes are ribozymes: [123] [124] the catalytic site is composed of RNA, and proteins hold no major structural role and are of peripheral functional importance. This was confirmed with the deciphering of ...
RNA can also act as a hereditary molecule, which encouraged Walter Gilbert to propose that in the distant past, the cell used RNA as both the genetic material and the structural and catalytic molecule rather than dividing these functions between DNA and protein as they are today; this hypothesis is known as the "RNA world hypothesis" of the ...
Independent replicators (probably RNA) Chromosomes: RNA world hypothesis: RNA as both genes and enzymes: DNA as genes; proteins as enzymes Prokaryotes: Eukaryotes: Can observe [clarification needed] Asexual clones: Sexual populations: Evolution of sex: Protists: Multicellular organisms — animals, plants, fungi: Evolution of multicellularity ...
This concept is known as the RNA world hypothesis. According to this hypothesis, the ancient RNA world transitioned into the modern cellular world via the evolution of protein synthesis, followed by replacement of many cellular ribozyme catalysts by protein-based enzymes.
The PAH world hypothesis is a speculative hypothesis that proposes that polycyclic aromatic hydrocarbons (PAHs), known to be abundant in the universe, [178] [179] [180] including in comets, [181] and assumed to be abundant in the primordial soup of the early Earth, played a major role in the origin of life by mediating the synthesis of RNA ...
A scenario is a set of related concepts pertinent to the origin of life (abiogenesis), such as the iron-sulfur world.Many alternative abiogenesis scenarios have been proposed by scientists in a variety of fields from the 1950s onwards in an attempt to explain how the complex mechanisms of life could have come into existence.
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.
In the late 1960s, Orgel proposed that life was based on RNA before it was based on DNA or proteins. His theory included genes based on RNA and RNA enzymes. [17] This view would be developed and shaped into the now widely accepted RNA world hypothesis. Almost thirty years later, Orgel wrote a lengthy review of the RNA World hypothesis. [18]