1.3 The Sodium Potassium Pump

Question 1

The sodium potassium pump transports Ions against a steep concentration gradient. Where does it get this energy from? And what does it use it for?

Answer 1

From the hydrolysis of ATP
To establish and maintain ion gradients

Question 2

The sodium potassium pump actively transports sodium ions…

Answer 2

Out of the cell

Question 3

The sodium potassium pump actively transports potassium ions..

Answer 3

Into the cell

Question 4

Step 1
The pump has a high affinity for sodium ions inside the cell. How many bind to the pump?

Answer 4

3

Question 5

Step 2
Binding occurs AND the pump is phosphorylated by ATP… this causes … and the result of this is ….

Answer 5

The conformation of the protein to change
This causes the affinity for sodium ions to decrease
So sodium ions are released outside of the cell

Question 6

Step 3
Potassium ions bind outside the cell. Dephosphorylation occurs and so the conformation of the protein changes again. This means that…

Answer 6

The potassium ions are taken into the cell
The affinity then returns to the start

Question 7

Explain fully how the sodium potassium pump works

Answer 7

The sodium potassium pump actively transports sodium ions out of the cell and potassium ions into the cell.
The pump has a high affinity for sodium ions inside the cell. 3 bind to the pump.
Binding occurs and the pump is phosphorylated by ATP
The conformation of the protein changes and the affinity for sodium ions decreases
This means sodium ions are released outside of the cell
2 Potassium ions bind outside of the cell
Dephosphorylation occurs and the conformation of the protein changes
Potassium ions are taken into the cell and the affinity returns to start.

Question 8

How many potassium ions bind

Answer 8

2

Question 9

The sodium potassium pump accounts for a huge proportion of …… in many organisms

Answer 9

Basal metabolic rate

Question 10

In the small intestines the glucose transporter responsible for glucose symposium transports…

Answer 10

Sodium ions and glucose at the same time and in the same direction
Sodium enters the cell down their concentration gradient
Glucose enters the cell against their concentration gradient

Question 11

In intestinal epithelial cells the sodium potassium pump creates ….

Answer 11

A sodium ion gradient across the plasma membrane