Which statement about signal transduction is true?

Signal transduction involves the process by which cells communicate with each other and respond to external signals. This communication is crucial for various cellular processes, such as growth, differentiation, and response to environmental changes.

When a signal, like a hormone or neurotransmitter, binds to a receptor on a target cell, it triggers a series of biochemical events that can lead to a response. This process can occur through direct cell-to-cell interactions or via signaling molecules that travel through the extracellular space. Thus, the involvement of communication between cells is a fundamental aspect of signal transduction.

The notion that signal transduction only involves membrane-bound receptors isn't entirely accurate because some signals can also affect intracellular receptors. Additionally, while signal transduction pathways often feature secondary messengers, they do not always require them; there's a diversity of pathways depending on the signal and the receptor's nature. The assertion that this process only occurs in prokaryotic cells is incorrect, as it is a critical mechanism in both prokaryotic and eukaryotic organisms, with many well-known pathways found in multicellular organisms.