Ion Channels I Flashcards
What are ion channels?
Ion channels are pore-forming membrane proteins that allow ions to pass through the channel pore.
What is used to describe the cell membrane?
Impenetrable as charged molecules can’t get through the lipid bilayer.
What does the plasma membrane contain?
Two layer of tightly packed lipid molecules which are NOT permeable to polar molecules of charged particles.
What are the 3 main specialised transport proteins?
Ion Channel / Ion Carrier / Ion Pump
What is digoxin?
Used to treat heart failure.
What are bumentanide and furosemide known as?
Diuretics = helps the body get rid of salt and water.
What is the mechanism which allows the ion pores to be open?
A gating mechanism is required in order to open the pore : This means that the channel needs to be activated.
Is ATP required for ion channels?
NO = they rely on an electrochemical gradient.
What is the movement of ions like?
The movement is very quick = high transfer rate.
What are the 3 main types of gating mechanisms?
Voltage / Ligand / Mechanical
Explain the 3 main ligand gated channels.
Neurotransmitter Receptor = Ligand binds onto a neurotransmitter.
Ca2+ / K+ activated channel = Calcium channel is activated by an intracellular molecule, Calcium.
Cyclic nucleotide gated channel = Binding of cyclic nucleotides.
It is very sensitive to changes in Ca2+ levels -> hyper-polarisation and depolarisation can occur.
What is cyclic nucleotide gated channels important for?
Important in olfactory and visual receptors.
What are the 4 main voltage - gated channels?
Na+
Ca2+
K+
Cl-
What is the mechanism of voltage - gated channels?
Ion flow occurs when membranes potentials change.
A gated mechanism is present and therefore, pore only opens when the channel is activated.
What determines the movement of ions?
Electropotential gradient
