Origin Of life

Origin of life studies

Keywords: - PROCESS - NATURAL - ORIGIN- EVIDENCE.

Scientists cannot directly address how life on Earth arose, they can formulate and test hypotheses about natural processes that could account for various intermediate steps, consistent with the geological evidence.  Alexander Oparin and J. B. S. Haldane independently proposed nearly identical hypotheses for how life originated on Earth. 

 Miller - Urey experiment:

Keywords: AMINO ACIDS - MOLECULES - ORGANIC - PRODUCED - CELLS LIVING.

Stanley Miller and Harold Urey tested the first step of the Oparin-Haldane hypothesis, as a result, the following emerged chimical reactions that produced a variety of organic molecules, some of which are the basic building blocks of life, such as amino acids.

Organic molecules form meteors:

Keywords: METEORITES - ORGANIC - MOLECULES - LIFE - EARTH.

Meteors that have landed on Earth have revealed that they contain many organic molecules. The organic matter contributed significantly to the organic molecules available at the time that life on Earth began.

Enzymatic activity and hereditary information in the one polymer: The RNA world hypothesis :

Keywords: ARN - HEREDITARY - ORIGIN - INFORMATION - GENETIC.

The discovery by Thomas Cech  catalytic RNA molecules, a single molecule or familyof similar molecules could potentially store genetic information and replicate themselves, with no proteins needed initially.

Protocells: Self- replicating and metabolic enzymes in a bag: 

Keywords: GRADIENTS - ENERGY - METABOLISM - SELF REPLICATING - RNA.

Cells also maintain large differences in concentration (gradients) to drive transport processes and cellular energy metabolism.