Final answer:
Voltage-gated channels rely on changes in electrical potential across the cell membrane to open or close, which is crucial for processes like neurotransmission and muscle contraction.
Step-by-step explanation:
In voltage-gated channels, the conformational state of the channel depends on the difference in ionic charge on the two sides of the membrane. These channels open when the transmembrane voltage changes, which can be triggered by a change in the electrical potential across the cell membrane. Particular amino acids within the structure of the protein are sensitive to changes in charge, prompting the pore to open to the selected ion. Voltage-gated channels are essential in cells involved in the transmission of electrical impulses, such as nerve and muscle cells, leading to critical functions like neurotransmission and muscle contraction.