BIOL 2P05 Lecture Notes - Lecture 19: Polyphyly, Comparative Genomics, Carl Woese
1 Mar 2018
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Document Summary
1980s researchers discovered rna can act as enzymes. Many present-day protein-based enzymes need rna co-factors to work. Catalytic site of the ribosome (translation of rna to protein) is formed entirely from rna. Dna are constructed by first synthesizing a ribonucleotide intermediate then removing a hydroxyl. Another experiment illustrated rna"s ability to mutate sequence. Similar experimental setup as spiegleman, but added a chemical that binds to rna to inhibit replication. After a few hours, variants arose, capable of replication. Paul and joyce demonstrated rna can catalyze reactions involved in its own assembly. T ligates a & b to form an rna identical to itself. Can take pieces of rna to make more of itself. Shift from rna to dna for genetic transmission. Roles of hgt in the origin of life. Carl woese proposed that during early cell evolution horizontal gene transfer was apowerful forse, leading to more complex cellular organisms.
