Question

When the extracellular signals, like hormones, are transduced into intracellular signals, what are the intracellular signals called ___________.

Answer 1

Intracellular signals generated as a result of hormone-receptor binding on the extracellular surface are called second messengers, which play a crucial role in the signal transduction process leading to cellular responses.

Step-by-step explanation:

Extracellular signals such as hormones interact with cells through a process known as signal transduction, activating intracellular responses. Hormones that cannot cross the cell membrane bind to external receptors, initiating a chain of events inside the cell. The hormone that binds on the surface of the cell is known as a first messenger, which triggers a second messenger inside the cytoplasm. This second messenger carries out the action initiated by the first messenger, often resulting in a phosphorylation cascade. Such signaling can lead to a change in the cell's activities, including the production of proteins and enzymes, changes in membrane permeability, or the regulation of gene transcription within the nucleus. The second messenger acts downstream in the signaling pathway to ensure the proper cellular response to the external hormone signal.

In summary, when hormones bind to cell surface receptors, they activate second messengers that are pivotal for propagating the signal within the cell, leading to the appropriate cellular response without the hormone itself entering the cell.