Final answer:
None of the options listed (hormones, neurotransmitters, cytokines, and growth factors) are incorrect; they all can be specific ligands for cell surface receptors.
Step-by-step explanation:
The question is asking which of the following is NOT a typical ligand for specific cell surface receptors: a. Hormones, b. Neurotransmitters, c. Cytokines, d. Growth factors, e. None of the above. The answer is e. None of the above, because all of the listed options (hormones, neurotransmitters, cytokines, and growth factors) are indeed typical ligands for specific cell surface receptors.
Hormones, like insulin, often bind to receptor tyrosine kinases, leading to a series of steps including the phosphorylation of tyrosine residues.
Neurotransmitters, such as dopamine, typically bind to G-protein-linked receptors, which often results in the increase of certain second messengers like cAMP. Cytokines and growth factors also bind to specific receptors and trigger various signaling pathways inside cells.