Day 18: Operon System

Today we reviewed the Operon system.

Here are the notes for the operon system:

• It ties in nicely with protein synthesis
• These are used because we don't always want to use our energy to constantly make proteins and mRNA.

There are two types of operon systems one is a repressible system and one is a inducible system.

The repressible one is a switch from on to off. When a system is on that means that RNA polymearse is working and the DNA is getting transcribed and translated and proteins are being created. At the beginning of this system there is a promotor and there is an operator. This operator in a repressible operon system is at first is unlocked. Because it is unlocked and mRNA and proteins are created polypeptides called tryptophan is made and then this makes the inactive repressor switch to active which goes into the operator and blocks and locks it so there is no more tryptophan or proteins or mRNA being created.

The inducible system is a switch from off to on and the operator is already blocked and locked. The system therefore can't let RNA polymearse pass thru to do protein synthesis. There is an active repressor working to block the RNA. However, when something like lactose becomes present then it will travel to the repressor and "bug" it and turn the repressor into a shape that doesn't fit into the lock box and therefore it is booted out of the operator and the RNA polymearse can once again function. The DNA once again can be transcribed and translated and enzymes can be produced such as lactase the enzyme that eats up lactose. Once lactase digests the lactose then the repressor becomes active again.

It really depends on what our bodies want to produce and what we need.