Quiz 1

Question 1

What are the ion concentrations of sodium in ICF/ECF, and what is ge equilibrium potential?

Answer 1

ICF: 15 mM
ECF: 145 mM
Equilibrium potential: +60mV
Sodium enters the cell

Question 2

What are the ion concentrations of potassium in ICF/ECF and what is the equilibrium potential?

Answer 2

ICF: 150 mM
ECF: 5 mM
Equilibrium potential: -90mV
Potassium leaves the cell

Question 3

What are the ion concentrations of chlorine in ICF/ECF, and what is the equilibrium potential?

Answer 3

ICF: 108mM
ECF: 10mM
Equilibrium potential: -63mV

Question 4

Explain sodium potassium pump?

Answer 4

Sodium potassium pump hydrolyzes 1ATP for every 2 K+ it pumps in against its concentration gradient INTO the cell and for every 3 Na+ it pumps OUT the cell
Prevents gradient from being lost (loss of gradient results in loss of tension which results in loss of ability to do work)

Question 5

Why is ion movement important?

Answer 5

Ion movement permits generation and propagation of electrical signals that send information to/from brain leading to nerves and muscle function, and sensation and movement

Question 6

Explain why the electrochemical driving force on Na is higher than for K.

Answer 6

Chemical: higher concentration of sodium outside cell than inside, so it will flow down its concentration gradient. Potassium has a higher concentration inside the cell, so it will flow outside the cell( down its gradient)
Electrical: cell is more negative inside so both cells will be attracted inward