Final answer:
Gated ion channels allow the passage of multiple ions, not just one at a time, following a specific stimulus. The closing and opening of these gates are crucial for physiological functions like neuron signaling and muscle contractions.
Step-by-step explanation:
The statement that a gated ion channel opens its gate, lets one ion across, and then closes is false. Gated ion channels in cell membranes control the movement of ions, but when they open, they can allow many ions to pass through rather than just a single ion. Following a specific stimulus, such as a chemical or electrical signal, the gate opens, and ions flow through the channel until the gate closes again. This process is critical in various physiological functions, including neurotransmission, muscle contractions, and maintaining the resting potential of cells.
Example of Gated Ion Channels in Action
In the case of nerve cells, the activation gate of the sodium gated channels opens when the membrane potential exceeds a certain threshold, allowing sodium ions (Na+) to flow into the cell. Subsequently, the inactivation gate closes after a very short period, halting the influx of sodium ions. This sequence of opening and closing facilitates the creation of an action potential, a crucial step in neuronal communication.