Final answer:
Extrinsic receptors, likely referring to hormone receptors like tyrosine kinase receptors and G-protein-linked receptors, are involved in transmitting signals from hormones and other ligands across the cell membrane to initiate various cellular responses.
Step-by-step explanation:
The question 'Why do we have Extrinsic Ub receptors? How do they work?' pertains to the role of specific hormone receptors within the human body. To address this inquiry, it is important to clarify that 'Extrinsic Ub receptors' might be a typographical error or a misunderstanding. Commonly discussed hormone receptors related to extracellular signaling include tyrosine kinase receptors and G-protein-linked receptors.
Tyrosine kinase receptors are crucial for the function of hormones and growth factors. They contain an extracellular binding site for ligands such as insulin. Once the ligand binds, the intracellular side of the receptor is activated to phosphorylate other proteins, which initiates a cellular response. This system relies on the equilibrium constant, k, to govern the likelihood of ligand-receptor binding.
G-protein-linked receptors, on the other hand, activate a membrane protein called a G-protein upon ligand binding. The G-protein then affects other membrane components, such as ion channels or enzymes, to carry out a cellular response. These receptors are identified by their transmembrane domains and specific extracellular ligand-binding domains.
Both types of receptors help relay external signals into the cell, thereby regulating various physiological processes, including the excretory system.