To initiate a signal transduction pathway, a signal binds to a receptor protein usually located in the
A) nucleus.
B) plasma membrane.
C) ER.
D) cytoplasm.

Question

Quizplus · Accepted Answer

Signal transduction pathways usually start with a signal molecule binding to a receptor protein on the plasma membrane. This can lead to the activation of intracellular signaling molecules and ultimately lead to changes in gene expression or other cellular responses. Receptor proteins located in the nucleus or cytoplasm are involved in other cellular processes, such as gene regulation and protein degradation, but not typically for initiating signal transduction pathways. The ER is involved in protein folding, modification, and transport, but does not play a direct role in signal transduction.

To Initiate a Signal Transduction Pathway, a Signal Binds to a Receptor