1.2 Summary of Section 1

• To survive and adapt, cells need to both sense their environment and communicate with each other.
• An important mechanism of cellular communication is the detection of extrinsic signals by specific receptors expressed on cell membranes. This mechanism of cellular communication is used by both prokaryotic and eukaryotic cells.
• Receptors trigger transduction events that relay information within cells. How a cell will respond to an extrinsic stimulus depends on the type of cell, the particular receptors it expresses on its cell membrane and its status.
• Quorum sensing is an ancient form of cellular communication that enables bacteria to coordinate their activities and live in a biofilm niche where they can proliferate.