In negative control, Repressor molecule is expected to be bound to the operator is there is no transcription.
Repressor molecule is a small protein which binds with the operator gene and prevents it from starting the synthesis of proteins called operon. The repressor molecule controls the amount of enzyme synthesis by reducing its rate of formation. Thelac repressor is a protein that represses (inhibits) transcription of the lac operon. In negative control, repressor molecule binds with the DNA molecule and blocks transcription process. A negative control is an experimental control that does not give a response to the test. The system of regulation in lactose andtryptophan operons outlined above is essentially a negative control.
You can use refraction which is the bending of light through a transparent material. Also the freezing and boiling points of water. One last one is the Cartesian five experiment, this shows the density of water. Hope this helped.
