In biochemistry, aligand is a substance that forms a complex with a biomolecule to serve abiological purpose. In protein-ligandbinding, the ligand is usually a molecule which produces a signal by binding to a site on a target protein.
Receptor mediated endocytosis is an endocytotic mechanism in which specific molecules are ingested into the cell. The specificity results from a receptor-ligand interaction. Receptors on the plasma membrane of the target tissue will specifically bind to ligands on the outside of the cell. An endocytotic process occurs and the ligand is ingested.
A very well studied example of receptor mediated endocytosis involves the metabolism of cholesterol.
The reduced the change of that matter
This is an example of negative feedback.
After a big meal, glucose levels in the bloodstream increases. The body recognises this change and goes through homeostasis, or the regulation of bodily state or internal environment.
The pancreas secretes insulin, which then binds to insulin receptors. This will result in the uptake of excess glucose from the bloodstream into cells and converted into glycogen to be stored in cells as energy storage molecules.
Since there is the counter effect of body (i.e. when blood-glucose concentration increases, the body sends a signal to decrease the blood-glucose concentration, this is called a negative feedback (instead of a positive feedback, which occurs if for e.g. the body signals cells to increase blood-glucose concentration even after blood-glucose concentration increased after a heavy meal).
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