What feature of voltage gated Na channels helps attract Na ions faster than just the concentration gradient?

The feature of voltage-gated sodium (Na) channels that attracts Na ions faster than what would be expected from the concentration gradient is the presence of negative charge.

Voltage-gated Na channels contain specific amino acids in their structure that carry negative charges. These negatively charged regions in the channel create an electrostatic attraction for positively charged sodium ions. As Na ions approach the channel, they are drawn in more efficiently due to this attractive force created by the negative charges, thereby increasing the rate at which sodium ions enter the cell when the channel is open. This charged environment enhances the movement of Na ions across the membrane beyond what the concentration gradient alone would facilitate, allowing for rapid depolarization of the cell during action potentials.

The other choices do not contribute to the rapid attraction of sodium ions. Large pore size relates to the ability of molecules to pass through but does not specifically enhance the attraction of Na ions. A rapid closing mechanism pertains to the overall functionality and timing of the channel's opening and closing, rather than ion attraction. Low permeability indicates how easily a substance can pass through the channel, but high permeability, not low, is what allows for the swift influx of sodium ions when the channels are activated.