The Origin of Life Option D1 D1.1-D1.4 Chapter 26 Campbell

D1.1: Describe four processes needed for the spontaneous origin of life on Earth  Think back to the cell theory Cells come from pre-existing cells But what were the first cells?  For these cells to have arisen from non-living material, four requirements would have had to be met …

Requirements  1. Simple organic molecules would need to be available  2. The simple molecules would need to have been assembled into polymers

Requirements  3. These abiotically produced molecules would need to have been packaged into membrane bound structures with a different internal chemistry from their surroundings  4. A mechanism that makes inheritance possible

Where did those organic molecules come from?  The experiments of Stanley Miller and Harold Urey Illustrated that simple organic molecules (like amino acids) can be produced in abiotic conditions 1953 University of Chicago (Yea!!) e_chem/Exobiology/miller.html e_chem/Exobiology/miller.html

Miller and Urey’s Apparatus  182/Urey-Miller.htm 182/Urey-Miller.htm  Stanley Miller!!

What they did …  Steam is passed through a mixture of methane, hydrogen, and ammonia At the time of their experiment, this mixture was thought to be representative of early Earth  Electrical discharges were used to simulate lightening

And they found …  In the “liquid trap” they collected amino acids, adenine and ribose Ran for about a week

D.1.3: State that comets may have delivered organic compounds to Earth  Comets and meteorites have been found to contain organic material Amino acids 1970  A meteorite; 7 amino acids, 2 of which are not found in living things on Earth  Originate in space

Other locations …  Deep sea vents volcanoes Gushing hot water Carry inorganic chemicals, like iron sulfide Represent readily accessible supplies of energy and raw materials  monomer organic compounds  Extraterrestrial