BIOL 1001 : Bio Exam 1 Notes
Document Summary
Fossil bacteria in rocks 3. 5 billion years old come from preexisting cells: half-life- very reliable way to date things. Dna can only reproduce itself with the help of large, complex protein enzymes the instruction for building these enzymes are located in dna itself. It is likely that the current dna-based system of information storage evolved from an earlier system: rna is the prime candidate for the first self-replicating informational molecule. In an experiment formed by cech & sidney in the 1980s, they discovered that a cellular reaction was catalyzed by rna, not a protein enzyme which was thought to be the only way for reactions to catalyze. In conclusion, prior to the dna-era, rna served as both the information- carrying genetic molecule and the catalyst for its own replication. Information flow: dna-rna-protein: dna transcribed into rna; rna is translated to a protein.
