EVIDENCES IN SUPPORT OF BIOCHEMICALORIGIN OF LIFE

Evolution of complex  organic molecules from simple molecules  ,as held by Oparin,has been proved by many scientists all over the world .This is well supported  by experimental  or  laboratory  studies.in this context  ,Stanley miller [1953] has taken alead to provide  experimental proof .                                                                                              Stanley Miller's Experiment                                                                                                                             IN 1953 ,Stanley Miller performed a simulation experiment  under  guidance of his professor ,Harold Urey  to test hypothesis of biochwmical origin of life .In this  experiment ,he  tried to create thse conditions  that might  have existed  in the primitive  atmosphere .For this  he built an apparatus as shown in Fig .2.1  to circulate CH4,NH3,H2and H20 and pass to circulate CH4,NH3,H2andH2O and pass electric  discharges.The assemblyu  of the  apparatus consisted  of two  flasks- one  large and another small , a condenser  and glass tubes .Two tungsten electrode  ,connected to an  electric source  were fitted  in the large flask  to provide  energy  of electric discharge ,simulating effect of lightning  of  the primitive  atmosphere and for this reason ,Stanley Miller's  apparautus  is called  Spark .                                                                         Discharge Apparatus .The  large flask contained  a  mixture of CH4,NH3 and H2[2:1:2]  and the small flask   had water  .The experiment  started  with switching on the electric source  and boiling the water  and it continued  for  a week .Then , on observation ,Miller  found  a dark coloured condensed  liquid .He  collect it and analysed  chromatographically .The analysis showed that  the fluid  was a mixture  of sugars,amino acids [e.g., glycine ,alanine ,aspartic acid,etc.]and  fatty acids .Miller's  this finding supports Oparin's theory  of origin of life  that during  course of origin of life , simple  molecules  evolved  into complex organic  molecules .                                                                                                                                                                                        Other Evidences                                                                                                                                           Oparin's  view has also been supported  experimentally  by Melvin and Calvin[1951] , Sydney.F.Fox[1964]  and Abelson ,Oro  and Kamat[1960,1965 ] .The latest support comes  from Dr.H.R.Khorana [1968]  who has synthesized  a DNA molecule ,consisting of 77nuccleotides ,in a test tube  .For this synthesis ,Dr.Khorana's synthesis of DNA molecule suggest that  during the course of origin of life ,nucleic acids  would have  formed  by linking  together of nucleotides  in the primitive  ocean.