ICPP 2 Pores, Channels And Transporters Flashcards
What does primary active transport use for energy?
ATP hydrolysis
What is Na+/K+ ATPase controlled by?
ATP hydrolysis
What type of ATPase is Na+/K+ ATPase?
What does this do
P type ATPase
ATP phosphorylates aspartate»_space; phosphoenzyme intermediate
What is the B subunit on the Na+/K+ ATPase for?
For inserting into plasma membrane
What does the a subunit in the Na+/K+ ATPase have attached to it?
What happens to it?
Aspartate
Phosphorylated by ATP hydrolysis»_space; phosphoenzyme
Function of Na+/K+ ATPase
- Forms Na and K gradients - needed for electrical excitability
-
Drives 2° active transport - control pH
- cell volume regulation
- calcium conc. regulation
- nutrient uptake
Where is Na+ conc higher?
Outside cell
Where is Cl- conc. higher?
Outside cell
K+ concentration outside cell
4mM
What is responsible for resting membrane potential?
Leaky K+ channels
What cotransporters are used for calcium removal?
- Ca2+ ATPase PMCA
- Na+/Ca+ exchanger NCX
- Ca2+ entering mitochondria
- sarco(endo)plasmin reticulum Ca2+ ATPase SERCA
What happens when Ca2+ enters the mitochondria?
- Takes H2O with it
- Cell swells, bursts + dies
- replaced with adipose tissue
How does the F1/F0 ATPase produce ATP?
1- 3 protons come to a protein + bind to F0
2- conformational change > F1 moves + turns shaft
3- aB heads open up
4- ADP + Pi come together
5- process repeats
6- ADP + Pi fuses > ATP made
7- 3 more protons bind > ATP released
What are gated channels?
Channels which open/close in response to different stimuli
Control movement of molecules in and out of cell
What are ligand gated ion channels?
Channels which open or close in response to ligand binding to a receptor
