Final answer:
True, the insulin receptor dimerizes following the binding of insulin. This dimerization is an essential step in the activation of the receptor's tyrosine kinase activity and subsequent insulin signaling inside the cell.
Step-by-step explanation:
The direct answer to the given question is a. True :
The insulin receptor does indeed dimerize in response to the binding of insulin, which is a single ligand-binding event.
Dimerization is a critical step in the activation of many receptor tyrosine kinases, including the insulin receptor. Upon insulin binding, the receptor undergoes conformational changes which allow two receptor molecules to come together, forming a dimer. This dimerization brings the intracellular domains of the receptors into close proximity, facilitating the tyrosine kinase activity where one receptor phosphorylates the tyrosine residues on the other. This phosphorylation serves as a signaling event that leads to further downstream effects like GDP being exchanged for GTP on signaling molecules and initiation of a cascade of cellular responses.
The insulin molecule after binding is eventually internalized in the cytoplasm during the process of endocytosis — a method by which cells absorb molecules from the outside environment — as part of the hormone signaling response.