Answer:
An amino acid activates the repressor so that the repressor binds to the operator and prevents transcription.
Explanation:
In an operon, promoter is followed by operator which is finally followed by the structural genes to be transcribed. RNA Polymerase binds to the promoter and initiates transcription. A repressor can negatively control the transcription process by binding to the operator so that the RNA Polymerase is not able to move forward and transcription is halted.
For example: in trp operon, tryptophan amino acid binds to the repressor molecule which leads to change in repressor's shape. The repressor is now able to bind to the operator and prevent transcription.
It helps break down waste and consume it as well as by eating dead organisms
Hope this helps :))
The B-pleated sheet is held together by hydrogen bonds between adjacent segments.
In an a-helix the side chains are located on the outside of the helix
The secondary level of protein structure refers to the spatial arrangements of short segments of the protein
While there is no graph provided and I cannot find the graph online, I will base my answer through theory.
In theory, the most common blood type is O+, followed by A+, then B+, then AB+. Rh negative blood is deemed to be rare. While the most common blood type is O+, the same blood type is also called the "universal donor" as a type O+ blood has no antigens attached in red blood cells therefore the probability of adverse reactions (i.e. hemolytic reactions) when transfused to other blood types are close to nil. In an emergency situation, wherein there is not enough time to do proper crossmatching, blood type O+ can be used therefore supplies of blood type O+ are easily depleted.
