Computer Simulation On The Origin Of Biochirality And The Mechanisms Regarding Protocells' Emergence In The RNA World

In biology,homochirality is a common property of amino acid and nucleotide,which are base component of proteins and nucleic acids,while it is rare in natural environment.How the life can emergence from the symmetric prebiotic environment and where the mirror symmetry breaking occur concerning the origin of life.By the mean of computer simulation,we studied the origin of homochirality in the context of the RNA world.The RNA chain performed template-directed ligation and montmorillonite clay catalyzed condensation show the autocatalysis ability,and the initiation of the autocatalysis reactions required long RNA chains,which may be the threshold.As the simulation result shows when the threshold is high,the autocatalysis reaction can amplify the initial asymmetry and result to the bifurcation of the system.The enantiomeric excess increases with the threshold.The chiral selectivity of RNA chains ensures the two autocatalysis reactions.The cross inhibited termination also plays an important role in the bifurcation.As the bifurcation of the system,the RNA chains can grow longer,thus the diversity of RNA can increase.As a result,the occurrence of ribozyme become easy,which may advance the bifurcation because of the stronger chiral selectivity and catalytic efficiency and meet the requirement of the RNA world's development.The emergence of cell may be a major transition in the evaluation of RNA world.Owing to the space limitation function of cell,it may be essential when the RNA world become prosperity,because the molecules cooperation may be ineffective without space limitation.We have simulated the emergence of cell,as the result shows,cell can ensure the space limitation for enzyme cooperation.Except that,the ability to resist parasites and the suitability to vast environment,especially the aqueous solution,may make up the disadvantage that the cell may limit the entrance of raw materials.In general,the form of cell may emergence more earlier under the pressure of natural selection and then become the basic unit of life.