Question

TTX irreversibly blocks the voltage-gated sodium channels so that sodium ions cannot enter. It blocks the action potential from R1 to R2. What is the effect of TTX on the voltage-gated sodium channels?

1) It increases the flow of sodium ions through the channels
2) It decreases the flow of sodium ions through the channels
3) It has no effect on the flow of sodium ions through the channels
4) It reverses the flow of sodium ions through the channels

Answer 1

TTX irreversibly blocks the voltage-gated sodium channels, decreasing the flow of sodium ions through the channels.

Step-by-step explanation:

TTX irreversibly blocks the voltage-gated sodium channels, preventing sodium ions from entering. This action of TTX decreases the flow of sodium ions through the channels. By blocking the sodium channels, TTX prevents the generation of action potentials from R1 to R2. Therefore, the correct answer is 2) It decreases the flow of sodium ions through the channels.