PCB 4674 Lecture Notes - Lecture 29: Ribosome, Racemic Mixture, Hydrogen Cyanide
21 Dec 2016
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First living thing: primordial form (darwin, 1859) or ida (initial darwinian ancestor: presumably begat a diversity of descendant lineages- most are extinct. One was the last common ancestor of all extant organisms- cenanscestor or luca (last universal common ancestor); history of these descendents constitutes tree of life. What was the first living thing: 1980s: two teams discovered small enzymes that could break and reform the chemical bonds that link nucleic acids together in chains; altman and cech; ribozymes. All known enzymes were made of proteins- this was rna. Proteins can perform all kinds of complicated biological processes, but cant store or transmit the information needed to replicate. Dna can store and transmit all of the information, but cannot perform any biological work. Rna can possess both a genotype and a phenotype. Ribozymes can have a folded state that can have an active site to enable the rna to catalyze a chemical reaction on a substrate, just like a protein enzyme.
