Class 23

        Today in class we reviewed Unit 3 and learned about the Operon System and Biotechnology. We first took a short quiz and then cleaned out the PGLO bacteria with bleach. We then talked about frameshift when adding or subtracting bases to change the protein. There is nonsense, no effect and missense. We then learned about repressible(on-off) and inducible(off-on) operon systems and the effect of aribonose or lactose has on the system. The operon system is a control system (controlling genes) making only useful proteins and conserving energy. In a repressible operon system, the repressor is inactive and the operator is on, so the RNA polymerase can come into the promoter, read the regulatory gene and makes tryptophan. When there is enough tryptophan, it goes into repressor and then changes it to become active. Then it goes it lock and blocks the RNA polymerase from reading the gene, shutting system off. The inducible operon system, the repressor is active and the operator is off, blocking the RNA polymerase from going through the gene. Lactose or arabinose can then come in and  sit in the protein repressor, changing its shape. Lactase or arabinase is then made and digests lactose or arabinose, unlocking operator and letting RNA polymerase through. We then related the operon system to the PGLO lab that has an inducible operon system. Biotechnology discusses restriction enzymes that cut DNA and RNA. We can isolate them and move them around.