Cation-exchange chromatography is used when the molecule of interest is positively charged, the stationary phase is negatively charged and positively charged molecules are loaded to be attracted to it. So, the amino acids with negative charge will elute the first. Glutamate, leucin, arginine is the order of elution because of their pI values ~3, ~6 ~10.
They are located in the liver the wall of the sinusoids.
Microscopes
Before the development of microscopes, the existence of cellular life was unknown. By examining a piece of cork, Robert Hooke first saw and named cells. Antony van Leeuwenhoek was the first person to see living cells.
C. Positive Feedback
This is because a response to a stimulus( low blood pressure) acts in the same direction as the stimulus ( even lower blood pressure).
This is opposed to negative feedback where the response would go in the operate direction of the stimulus ( I.e. blood pressure increasing in response to low blood pressure)
