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4.5 Synthesis of molecules for cell membranes of all creatures

　 [Chemical reaction by collision between H+ of solar wind and CO² in the early atmosphere]

Fig.13　The cell membrane of the first creature was that was produced by the collision of solar wind with CO₂ in the atmosphere of primitive Earth.

　Yuri-Miller had been carried out the experiment for origin of life by using CH⁴, H² and NH³. By the subsequent studies after Yuri-Miller’s experiment, it become to think that the atmosphere when the first life was born was oxidizing gases such as CO₂ and NOx. But CH₄, NH₃ and H₂ were generated by the collision of solar wind and atmospheric molecules on the Earth.

[Hydrocarbons in liquid state floating on the sea surface of early Earth]

　High-speed H⁺ had reacted with CO₂ in the primitive atmosphere to produce water to hydrocarbons. Hydrocarbon molecules with a small number of carbons evaporate on the Earth's surface and stay in the sky, but hydrocarbon molecules with a higher number of carbon atoms with a lower melting point and a higher boiling point than the surface temperature are present on the Earth's surface as a liquid.
　As shown in Table 1, hexadecan and octadecane were present in a liquid state in the primitive global environment. The molecules spread on the surface of the water because those are hydrophobic molecules and the specific gravity was less than 1. Linear chained molecules of C₁₆H₃₄ and C₁₆H₃₄ were gathered on the surface of the water by hydrophobic bonding. Most organisms' cell membranes consisted of hydrocarbons with 16 or 18 pices of carbon atoms.　Table.2 shows the data on chain of hydrocarbons (C_nH_2n+2) (Here, n=14～20).

　　　　　Table. 2 The chain hydrocarbon (C_nH_2n+2) (Here, n=14～20)

	Molecule	Melting point [℃]	Boiling point [℃]	Specific gravity [20℃]
Tetradecane	C14H30	4 to 6	253～257	0.76
Hexadecane	C16H34	18	287	0.773～0.776
Octadecane	C18H38	28～30	317	0.777
Icosane	C20H42	36～38	343.1	0.7886

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