Final answer:
The complex formed when insulin binds to its receptor and is internalized by the cell is an example of receptor-mediated endocytosis. This is a specific type of endocytosis essential for hormone signaling, leading to subsequent degradation of the hormone within the cell.
Therefore the correct answer is option is c) Endocytosis
Step-by-step explanation:
When insulin binds to its receptor, the complex is endocytosed into the cell. This process is an example of receptor-mediated endocytosis, which is a highly selective form of endocytosis where cells internalize molecules based on the specific binding of a ligand to cell-surface receptors. This is critical for hormone signaling as it allows for the controlled uptake and degradation of the hormone, thereby regulating its activity and its levels in the bloodstream.
In the case of insulin, once it has docked onto its receptor and exerted its action on the cell, such as changing the permeability of the cell membrane to glucose, the insulin-receptor complex can be taken into the cell. Here it is often degraded by lysosomes or by specific enzymes like the insulin degrading enzyme, typically in liver cells. The degradation process ensures that insulin's effects are not prolonged beyond their necessary duration, with the typical insulin molecule being degraded around 71 minutes after its release into circulation.