BIO 121 Lecture Notes - Lecture 9: Archaea, Phospholipid, Lipid Bilayer
8 Dec 2020
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Document Summary
Large molecules like dna/rna cannot pass through lipid bilayer. Nucleic acid replicator first seems plausible except. Primordial soup experiments: never produced rna polymer. Gunter wachtershauser: 1st catalysis by pyrite (iron disulfide) and not proteins/rna. Rna can form complex structure and catalytic activities. Protein synthesis is carried about by rna structure (ribosomes) Retroviruses can synthesize dna copies of rna molecules by reverse transcriptase. Reverse transciption (by the enzyme reverse transcriptase) Mrna can reverse transcribe to dna and inserted into genome. Sometimes called processed pseudogenese :no introns if inserted next to a functional transcriptional promoter sequence, they can be expressed. Cell membranes are needed to enclose and protect the molecular components: conserve macromolecules; Enclosed membranes can form spontaneously by phospholipids in aq: protocells. Early earth timeline later: earth cooled, liquid form a comet impacted; brought n2 and heat; Pre life: hot, vapor water; plenty of uv. Stomatolites: structures formed by cyanobacteria like organisms. Marine photosynthetic bacteria dominated earth 1-2 billion years.
