ion pumps and generation of ion gradients

Question 1

When is a membrane potential/an electrical potential difference created?

Answer 1

A membrane potential (an electrical potential difference) is created when there is a difference in electrical charge on the two sides of the membrane.

Question 2

For a solute carrying a net charge, the ____________ __________ and the ____________ ____________ _____________ combine to form the __________________ ____________ that determines the transport of the solute.

Answer 2

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

Question 3

Ion pumps, such as the sodium-potassium pump, uses energy from ____________ of __________ to establish and maintain ___ _______.

Answer 3

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

Question 4

The sodium-potassium pump transports _____ against a _____ concentration _________ using energy directly from _____ _____________.

Answer 4

The sodium-potassium pump transports ions against a steep concentration gradient using energy directly from ATP hydrolysis

Question 5

It actively transports sodium ions _____ of the cell and potassium ions into the _____

Answer 5

It actively transports sodium ions out of the cell and potassium ions into the cell

Question 6

Describe the process of the Sodium Potassium Pump

Answer 6

• The pump has high affinity for sodium ions inside the cell
• binding occurs
  phosphorylation by ATP
• conformation changes
  affinity for sodium ions decreases
• sodium ions released outside of the cell
• potassium ions bind outside the cell
• dephosphorylation
• conformation changes
• potassium ions taken into cell
• affinity returns to the start

Question 7

For each ATP hydrolysed, _________ ____ are transported out of the cell and ____ ___________ ____ are transported into the cell.
This established both ___________ gradient and an ___________ gradient.

Answer 7

For each ATP hydrolysed, three sodium ions are transported out of the cell and two potassium ions are transported into the cell.
This establishes both concentration gradients and an electrical gradient.

Question 8

Where is the sodium-potassium pump found?

Answer 8

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