BIOL 121 Lecture Notes - Lecture 7: Purple Bacteria, Stromatolite, Reducing Atmosphere
Document Summary
-earth formed 4. 6 billon years ago (1st atmosphere he and h2); earth"s gravity not strong enough to hold these light gases. 1st half billion years: too hot to allow water to accumulate on surface; hot. Abiotic synthesis: formation (slow) of organic molecules prebiotic soup. 2nd atmosphere: h2), co2, so2, co, s2, c12, n2, h2, nh3 and ch4. -earth cooled; h2o vapour condensed ocean formed. Reducing atmosphere prior to oxygen, when there i s no oxygen, redox reaction, different chemical reactions without oxygen. Origin of life on earth: living cells are complex collections of molecules and macromolecules. Dna stores the information for the amino acid sequences of proteins. Rna acts as the intermediary in the process of protein synthesis. Proteins form the foundation for the structure and activities of living cells: life requires the interplay between dna< rna and proteins for its existence and perpetuation.
