Answer/Explanation:
EGFR stands for epidermal growth factor receptor. It is a transmembrane protein acting as a tyrosine kinase receptor for epidermal growth factor ligands, which are associated with promoting cell division and proliferation. When epidermal growth factor binds to the receptor, it becomes activated and undergoes dimerization and autophosphorylation.
A mutation could occur making the receptor overactive. That is, it does not require ligand binding to become activated, meaning it is always in an "on" state. This would lead to uncontrolled proliferation, a hallmark of cancer.
The R group is what allows amino acids to form macromolecules with different properties. every amino acid has the same basic structure, the only difference is what the R group is made up of. The similarities allow the amino acids to form a chain while the differences allows them to have different functions. Hope this helped!
From a fungus called Verticillium.
Hope this helps!! :)