Non-living Synthesis


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•  The first cells must have arisen from non-living material

The theory that living cells arose from non-living matter is known as abiogenesis

This process is theorised to have occurred over four key stages:

  • There was non-living synthesis of simple organic molecules (from primordial inorganic molecules)
  • These simple organic molecules became assembled into more complex polymers
  • Certain polymers formed the capacity to self-replicate (enabling inheritance)
  • These molecules became packaged into membranes with an internal chemistry different from their surroundings (protobionts)

Miller-Urey Experiment

The non-living synthesis of simple organic molecules has been demonstrated by the Miller-Urey experiment

Stanley Miller and Harold Urey recreated the postulated conditions of pre-biotic Earth using a closed system of flasks and tubes

  • Water was boiled to vapour to reflect the high temperatures common to Earth’s original conditions
  • The vapour was mixed with a variety of gases (including H2, CH4, NH3) to create a reducing atmosphere (no oxygen)
  • This mixture was then exposed to an electrical discharge (simulating the effects of lightning as an energy source for reactions)
  • The mixture was then allowed to cool (concentrating components) and left for a period of ~1 week
  • After this time, the condensed mixture was analysed and found to contain traces of simple organic molecules

Overview of the Miller-Urey Experiment