Active transport

Question 1

Sodium potassium pump

Answer 1

In the cytosol sodium binds to the Na+/K+ ATPase.
One molecule of ATP is phosphorylated and a phosphate binds to the pump with high energy linkage.
Phosphorylation triggers conformation change and Na+ is ejected.
K+ binds and the pump dephosphorylates.
The pump returns to its original conformation and K+ is ejected.

Question 2

What is significant about the Na+ K+ ATPase

Answer 2

Both molecules are pumped against concentration gradients

Question 3

What are the 3 conformations for gated ion channels?

Answer 3

Closed- no movement of ions
Open - free diffusion of ions
Inactive (refractory - closed and cannot be opened

Question 4

What are transporters?

Answer 4

Enzymes that catalyse movement in a uni- or bi-directional way