Pick the correct statement regarding a voltagegated sodium c

Pick the correct statement regarding a voltage-gated sodium channel:

A. It has four intracellular loops composed of negatively charged amino acids that serve as the voltage sensor

B. It is made up of four separate subunits, encoded by different genes

C. It contains a \'ball and chain\' region that serves as the ion selectivity filter of the channel

D. It contains transmembrane regions with positively charged amino acids that serve as the voltage sensor

Solution

.D. It contains transmembrane regions with positively charged amino acids that serve as the voltage sensor.

Sodium channels consist of large subunits that associate with proteins, such as subunits.The -subunit has four repeat domains, labeled I through IV, each containing six membrane-spanning segments, labeled S1 through S6. The highly conserved S4 segment acts as the channel\'s voltage sensor. The voltage sensitivity of this channel is due to positive amino acids located at every third position.When stimulated by a change in transmembrane voltage, this segment moves toward the extracellular side of the cell membrane, allowing the channel to become permeable to ions.