How many potassium ions pass through if the ion channel opens for 1.0 {\rm ms}?

In summary, the biochemistry inside cells relies on ions like sodium, potassium, and calcium, which enter through ion channels formed by specialized proteins. A 0.30-nm-diameter potassium ion channel has been found to carry a current of 1.8 picoamperes. Using the equation Delta Q = I * delta t, it can be calculated that 11,250 potassium ions pass through the channel when it is open for 1.0 millisecond. When rounding to two significant figures, the answer is 11,000.
  • #1
deborahcurrie
6
0

Homework Statement


The biochemistry that takes place inside cells depends on various elements, such as sodium, potassium, and calcium, that are dissolved in water as ions. These ions enter cells through narrow pores in the cell membrane known as ion channels. Each ion channel, which is formed from a specialized protein molecule, is selective for one type of ion. Measurements with microelectrodes have shown that a 0.30-nm-diameter potassium ion ({\rm{{\rm K}}}^{\rm{ + }} ) channel carries a current of 1.8 {\rm pA}.

How many potassium ions pass through if the ion channel opens for 1.0 {\rm ms}?

Homework Equations



Delta charge (Q)=Current (I) * delta time
1 ion = 1.6E-19 C



The Attempt at a Solution


Delta Q=1.8E-12*1E-3=1.8E-15C

1.8E-15C/1.6E-19=11,250

Mastering physics wants 2 sig figs, so entered "11,000" which is wrong.
 
Physics news on Phys.org
  • #2
deborahcurrie said:
1.8E-15C/1.6E-19=11,250

Mastering physics wants 2 sig figs, so entered "11,000" which is wrong.

It looks right to me. Is it possible to enter "1.1e4"?
 
  • #3
That did it. Thanks for thinking of the tip!
 

1. How is the number of potassium ions passing through an ion channel calculated?

The number of potassium ions passing through an ion channel can be calculated by multiplying the conductance of the channel (in siemens) by the driving force (in volts). This gives the current, which can then be multiplied by the duration of time the channel is open (in seconds) to get the total number of ions that passed through.

2. What is the typical conductance of a potassium ion channel?

The conductance of a potassium ion channel can vary depending on the specific channel type and conditions, but it is typically between 10-100 pS (picosiemens).

3. How does the duration of the channel opening affect the number of potassium ions passing through?

The longer the channel is open, the more potassium ions will pass through. This is because the longer the channel is open, the more time there is for ions to flow through it. However, the rate of ion flow may decrease over time due to factors such as ion depletion or channel inactivation.

4. Can the number of potassium ions passing through an ion channel be affected by external factors?

Yes, the number of potassium ions passing through an ion channel can be affected by external factors such as the concentration of potassium ions in the surrounding environment, the presence of other ions that may compete for the channel, and the electrical potential across the membrane.

5. How does the number of potassium ions passing through an ion channel contribute to cellular functions?

Potassium ion channels play important roles in various cellular functions such as maintaining the resting membrane potential, regulating cell volume, and facilitating nerve and muscle cell communication. The number of ions passing through these channels can impact these processes and ultimately, influence the overall function of the cell.

Similar threads

Action Potential Through Ion Channel, Total Number of Ions Through
    • Introductory Physics Homework Help
Replies
13
Views
4K
What is the current density in the ion channel?
    • Introductory Physics Homework Help
Replies
2
Views
2K
How Many Potassium Ions Pass Through a 0.30-nm Channel in 1.0 ms?
    • Introductory Physics Homework Help
Replies
2
Views
6K

Hot Threads

Recent Insights

Back
Top