1. Primordial Cell Membrane

2. Overview  Structure  Function  Ingredients  Self-assembly  Challenges  Future Work  Structure  Function  Ingredients  Self-assembly  Challenges  Future Work

4. Cell Membrane  Bilayer  Amphiphilic molecules  Transport protein  Stabilizing protein, glycolipid, cholesterol  Bilayer  Amphiphilic molecules  Transport protein  Stabilizing protein, glycolipid, cholesterol

5. Function  Protection - from competing reagents - protect sensitive organic molecules from heat and radiation  what about amino acids found in meteorites?  Concentration - facilitating interaction between molecules - RNA world theory, inefficiencies of other methods  Compartmentalization / Organization  permeability  transport  Protection - from competing reagents - protect sensitive organic molecules from heat and radiation  what about amino acids found in meteorites?  Concentration - facilitating interaction between molecules - RNA world theory, inefficiencies of other methods  Compartmentalization / Organization  permeability  transport

6. Was primordial cell membrane capable of these functions ? If yes, then how important was cell membrane in the early origin of life?

7. Available ingredients  Plenty organic compounds (C, N, O, S, P) from: (10 7 kg / yr in modern day) 1.Interstellar space - from interior of stars - evidence from meteorites, cometary and asteroidal dust - concentrated and combined into more complex molecular species (eg PAH) Atmosphere Volcanoes Hydrotermal vents  Plenty organic compounds (C, N, O, S, P) from: (10 7 kg / yr in modern day) 1.Interstellar space - from interior of stars - evidence from meteorites, cometary and asteroidal dust - concentrated and combined into more complex molecular species (eg PAH) Atmosphere Volcanoes Hydrotermal vents

9. Then?  Self-assembly

10. Cell Membrane  Bilayer  Amphiphilic molecules  Transport protein  Stabilizing protein, glycolipid, cholesterol  Bilayer  Amphiphilic molecules  Transport protein  Stabilizing protein, glycolipid, cholesterol

12. Problems - Permeability ? How to get macromolecule inside - micelles, single chain - selected RNA species, also ion-conducting channel - hydration-dehydration / freeze-thaw cycles -High temperature, high concentration = high osmotic pressure -Divalent cations bind to anionic head groups = unstable -Specific pH - Permeability ? How to get macromolecule inside - micelles, single chain - selected RNA species, also ion-conducting channel - hydration-dehydration / freeze-thaw cycles -High temperature, high concentration = high osmotic pressure -Divalent cations bind to anionic head groups = unstable -Specific pH

13. Future work  Could a primordial cell membrane be formed in Earth’s early condition?  How to solve the permeability and transport problem?  Which amphiphilic molecules are the most stable?  Involvement of PAH in primordial cell membrane.  Could a primordial cell membrane be formed in Earth’s early condition?  How to solve the permeability and transport problem?  Which amphiphilic molecules are the most stable?  Involvement of PAH in primordial cell membrane.