Chapter 3 Lecture 6 - Membrane Transport

Question 1

Sodium-Potassium ATPase

Answer 1

Carrier protein, anti-porter, Moves Na+ and K+ up their concentration gradients

Question 2

Steps to Sodium-Potassium ATPase

Answer 2

1. 3 Na+ ions load into pump
2. ATP delivers one of its three phosphates to the pump, becomes ADP
3. Pump changes conformation, releases Na+ on the outside, changes shape of places where Na+ was
4. 2 K+ ions load into pump, phosphate released
5. Pump returns to original conformation
6. Pump releases K+ on the inside

Question 3

What is the relationship between Sodium-Potassium ATPase and the leaky plasma membrane

Answer 3

Sodium-Potassium compensates for it, maintains low levels of K outside, low Na inside

Question 4

How does Sodium-Potassium ATPase maintain the negative membrane potential

Answer 4

Pumps out 1 more positive ion than it pumps in