Final answer:
Ion channel-linked receptors bind specific ligands and open channels through the cell membrane for ions to pass through, changing the cell's membrane potential, essential for signal transduction especially in neural communication.
Step-by-step explanation:
Ion Channel Coupled Receptors
Ion channel-linked receptors, also known as ionotropic receptors or ligand-gated channels, are a type of cell-surface receptor crucial for signal transduction in cells. These receptors bind to a specific ligand and undergo a conformational change that opens a channel through the cell membrane. This channel allows specific ions such as sodium (Na+), calcium (Ca2+), magnesium (Mg2+), and hydrogen (H+) to pass through, leading to changes in the cell's membrane potential.
These receptors have extensive membrane-spanning regions with hydrophobic amino acids that allow them to interact with the hydrophobic interior of the phospholipid bilayer. The inside of the channel is lined with hydrophilic amino acids which facilitate the passage of polar molecules like water and ions. Ion channel-linked receptors play a vital role in neural communication, as seen when neurotransmitters bind to these receptors on neurons, triggering the influx of sodium ions and causing a signal transmission.
Mechanosensitive ion channels are another type of gated ion channels that respond to mechanical stress or deformation of the plasma membrane. For instance, stereocilia in the human ear are connected to mechanosensitive ion channels that transduce sound into neural signals.