Question

How do membrane receptors function in contact signaling?

a) By releasing neurotransmitters into the synapse.
b) By transmitting electrical signals along axons.
c) By binding with signaling molecules from neighboring cells.
d) By initiating apoptosis in response to external stimuli.

Answer 1

In contact signaling, membrane receptors function by binding with signaling molecules from neighboring cells, initiating a signaling cascade which results in various cellular responses.

Step-by-step explanation:

Membrane receptors function in contact signaling primarily by binding with signaling molecules from neighboring cells. This interaction initiates a signaling cascade within the cell, which translates the extracellular signal into an intracellular action, potentially leading to a vast array of cellular responses. For instance, receptors integrate with the extracellular matrix to initiate a signaling pathway inside the cell. However, if a cell detaches from the extracellular matrix, the absence of signaling can lead to apoptosis as part of a mechanism to prevent cells from proliferating inappropriately, which is common in metastatic cancer cells.