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Many biomolecules, such as L-glutamic acid, are asymmetric, and occur in living systems in only one of the two possible forms, in the case of amino acids the left-handed form. Prebiotic chemistry would produce both forms, creating a puzzle for abiogenesis researchers. [280]
The concept of life forms living on the surface of neutron stars was proposed by radio astronomer Frank Drake in 1973. Drake said that the atomic nuclei in neutron stars have large variety which might combine in supernuclei, analogous to the molecules that serve the base of life on Earth.
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. These include hypothesized ancient environments that might have been favourable for the origin of life, and possible biochemical mechanisms.
Spontaneous generation is a superseded scientific theory that held that living creatures could arise from nonliving matter and that such processes were commonplace and regular. It was hypothesized that certain forms, such as fleas , could arise from inanimate matter such as dust, or that maggots could arise from dead flesh.
Certain chemicals found in naturally occurring petroleum contain chemical and structural similarities to compounds found within many living organisms. These include terpenoids , terpenes , pristane , phytane , cholestane , chlorins and porphyrins , which are large, chelating molecules in the same family as heme and chlorophyll .
Rock and dust samples retrieved by NASA from the asteroid Bennu exhibit some of the chemical building blocks of life, according to research that provides some of the best evidence to date that ...
The relative chemical complexity of the nucleotide and the unlikelihood of it spontaneously arising, along with the limited number of combinations possible among four base forms, as well as the need for RNA polymers of some length before seeing enzymatic activity, have led some to reject the RNA world hypothesis in favor of a metabolism-first ...
More research is needed to determine whether the virus poses any threat to humans, Parry said. Queensland researchers plan to work on developing vaccines for this family of viruses, according to ...