Action Potential with Nerve Cell and Finding Power

  • #1
191
0

Homework Statement



During an action potential, Na + ions move into the cell at a rate of about 3 x 10^-7 mol / m^2 s. How much power must be produced by the "active Na+ pumping" system to produce this flow against a + 30 mv potential difference? Assume that the axon is 40cm long and 30 mu m in diameter.

Homework Equations



P = IV
maybe R = ρL / A

The Attempt at a Solution



I understand I need to use P=IV but I don't understand how to incorporate the measurements of the axon without knowing the resistivity of the liquid. Should I assume water?

P = (3.7 * 10^-7 mol/m^2 s)(0.03 V)
P ≈ 9.09 * 10^-9 W
 

Answers and Replies

  • #2
gneill
Mentor
20,925
2,866
The diffusion rate is given in terms of moles per unit area per second. Use the axon dimensions to estimate area. You'll also have to convert the moles of charges into actual charge units (what's the unit charge of an Na+ ion in coulombs?).
 

Related Threads on Action Potential with Nerve Cell and Finding Power

Replies
1
Views
976
  • Last Post
Replies
5
Views
779
Replies
8
Views
128
  • Last Post
Replies
4
Views
1K
  • Last Post
Replies
1
Views
3K
  • Last Post
Replies
2
Views
1K
  • Last Post
Replies
1
Views
784
  • Last Post
Replies
1
Views
8K
Replies
2
Views
12K
Replies
10
Views
494
C
Top