Membrane Proteins (b) Ion Transport Pumps and Generation of Ion Gradients

Question 1

EPD

For a solute carrying a net charge, ________ and the ____ combine to form the electrochemical gradient that determines the transport of the solute

Answer 1

The concentration gradient and the electrical potential difference

Question 2

A membrane potential (an electric potential difference) is created when…

Answer 2

There is a difference in electrical charge on the two sides of the membrane

Question 3

Ion pumps, such as the sodium-potassium pump uses the energy from the hydrolysis of ATP to…

Answer 3

Establish and maintain ion gradients

Question 4

The sodium-potassium pump transports ions against a…

Answer 4

Steep concentration gradient using energy directly from ATP hydrolysis.

Question 5

Sodium-potassium pump actively transports sodium ions out of the cell and potassium ions into the cell

Question 6

Steps of sodium-potassium pump

Answer 6

1. The pump has a high affinity for sodium ions inside the cell
2. Binding occurs
3. phosphorylation occurs by ATP
4. Conformation changes
5. Affinity for sodium ions decreases
6. Sodium ions released outside of the cell
7. Potassium ions bind outside of the cell
8. Dephosphorylation
9. Conformation changes
10. Potassium ions taken into the cell
11. Affinity returns to start

Question 7

Fo each ATP hydrolysed…

Answer 7

Three sodium ions are transported out of the cell and two potassium ions are transported into the cell

Question 8

This transport of ions establishes both…

Answer 8

Concentration gradients and an electrical gradient

Question 9

The sodium-potassium pump is mostly found in animals, accounting for a high proportion of the…

Answer 9

Basal metabolic rate in many organisms

Question 10

In the small intestine, the active transport of glucose is driven by..

Answer 10

The sodium gradient created by the sodium-potassium pump

Question 11

In intestinal epithelial cells the sodium-potassium pump generates a…

Answer 11

Sodium-ion gradient across the plasma membrane

Answer 12

Sodium ions enter the cell down their concentration gradient; the simultaneous transpoort of glucose pumps glucose into the cells against its concentration gradient

Question 13

The glucose transporter responsible for the glucose symport transports…

Answer 13

Sodium ions and glucose at the same time and in the same direction