Question

Patch-Clamp instruments allow researchers to measure the opening and closing of a single channel in a membrane. A typical acetylcholine receptor channel passes about 5 pA (picoamperers) of ionic current over a period of 5 msec at -60mV. Given that an electric current of 1 A is about 6.2x10^18 electrical charges per second, how many ions (potassium or sodium) pass through the channel during the time that it is open?

Answer 1

Each potasium or sodium ion is a +1 charge particle. Its mean that every ion is a single charged particle.

                   Time=t=510^-3 sec                               milli=10^-3 sec

                   V=-60mV

                          It is given that the current of 1A is about 2.610¹⁸ q. Here q represent charges.

                       we also know that every ion is a single charge particle. Its mean that number of charges are same to the number of ions.

                                    number of ions = n= (2.610¹⁸ q)(510^-12A) / 1A

                                                           =n=13000000q

                                We know that number of charge q= number of ions

                                                       n=13000000ions      pass through the channel in the given time