2.2 - ATP-dependent Pumps And Ion Exchangers

Question 0

Describe the Plasma Membrane Ca2+ ATPase (PMCA)

Answer 0

High affinity
Low capacity
Important in maintaining low intracellular [Ca2+]

Question 1

Why is the sodium-potassium pump important?

Answer 1

Forms Na+ and K+ gradients that are needed for electrical excitability
Drives secondary active transport

Question 2

Describe the SarcoEndoplasmic Reticulum Ca2+ ATPase

Answer 2

Drives Ca2+ against concentration gradient into ER stores
High affinity
Low capacity

Question 3

Describe the Sodium-Calcium exchanger

Answer 3

Electrogenic
Secondary active transporter
Reverses when cell membrane is depolarised
Reverses during ischaemia to maintain the [Na+] gradient

Question 4

Describe the Anion Exchanger

Answer 4

Transports Cl- in and HCO3- out

Can be reversed

Question 5

What channels are involved in the control of resting intracellular [Ca2+]?

Answer 5

PMCA
SERCA
NCX
Mitochondrial Ca2+ uniports

Question 6

What channels are involved in pH regulation?

Answer 6

NHE
Na+ dependent Cl-/HCO3- exchanger
NBC - brings in Na+ and HCO3- ions and expels Cl- ions
Anion exchanger

Question 7

How is cell volume regulated?

Answer 7

Through the transport of osmotically active ions
If the cell is shrinking ions are brought in
If the cell is swelling ions are extruded