Final answer:
In response to a hormone, neurotransmitter, or paracrine messenger, a cell must have specific receptors for recognition and response. Hormones interact with cell surface receptors, initiating cell-signaling pathways that lead to cellular changes.
Step-by-step explanation:
In order to be stimulated by a hormone, neurotransmitter, or paracrine messenger, a cell must possess the specific receptors for the neurotransmitter on the postsynaptic cell.
These receptors are necessary for the cell to recognize and respond to the signaling molecule. Hormones must interact with cell membrane receptors, which are usually associated with a G protein, leading to a signaling cascade and eventual cellular response.
Hormone receptors can induce cell-signaling pathways and mediate changes in target cells in the presence of hormones.
For hormones that cannot enter cells directly, they convey information to the cytoplasm, triggering a variety of cellular responses. In short, a hormone is released in response to a stimulus, travels through the body, and then binds to receptors on the target cell to elicit a response.