1.3b Ion transport and generation of ion gradients NEED TO GO OVER

Question 1

Solute carrying a net charge

Answer 1

For a solute carrying a net charge, the concentration gradient and the electrical potential difference (voltage) combine to form the electrochemical gradient that determines the transport of solute.

Question 2

How do ions pumps get energy?

Answer 2

Ion pumps such as the sodium-potassium pump uses energy from the hydrolysis of ATP to establish and maintain ion gradients.

Question 3

Sodium potassium pump

Answer 3

The sodium-potassium pump transports ions against a steep concentration gradient using energy directly from ATP hydrolysis.
It actively transports sodium ions out of the cell and potassium ions into the cell.

The pump is found in most animal cells, accounting for a high proportion of the basal metabolic rate in many organisms.

Question 4

The process of sodium potassium pump

Answer 4

The pump has high affinity for sodium ions inside the cells.
Binding occurs and the pump is phosphorylated by ATP.
The conformation of the protein changes and the affinity for sodium ions decreases. This means the sodium ions are released outside of the cell.
Potassium ions bind outside 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 5

Small intestine

Answer 5

In the small intestine the sodium gradient created by the sodium potassium pump drives the active transport of gluclose.

Question 6

Glucose transporter

Answer 6

The glucose transporter responsible for this glucose symport transports sodium ions and glucose at the same time and in the same direction.

Question 7

Why is the sodium-potassium pump important?

Answer 7

Generation and maintenance of ion gradients for resting potential in neurons.

Glucose transport in small intestine.