Functions of Channels and Transporters Flashcards
what is the electrochemical gradient
a gradient consisting of a chemical gradient and an electrical gradient. the difference can be interpreted as a type of PE available to do work in the cell
what is membrane potential
the difference in electric potential between the interior and the exterior of a biological cell
what are the functions of membrane potential
- gives the cell the power to operate a variety of molecular devices embedded in the membrane
- transmitting signals
what is the nernst equation used for
calculating the membrane potential based on internal and external concentrations of ion
what is the specific inhibitor for K+ in the Na+ K+ pump
ouabain
describe how a NT synapse works
a NT is released from the presynaptic neuron and binds to a receptor on the post synaptic neuron to activate an electrical response or second messenger pathway
describe how an electrical synapse works
presynaptic and postsynaptic cell membranes are connected by a gap junction that pass electric current
how are ion channels different from aqueous pores
they show ion selectivity and not continuously open
give the location and function of K+ leak channels
located in plasma membrane
function: maintain resting membrane potential
give the location and function of voltage gated Na+ channels
location: plasma membrane of nerve cell axon
function: to generate APs
give the location and function of voltage gated K+ channels
location: plasma membrane of nerve cell axon
function: to return membrane to resting potential after AP initiation
give the located and function of voltage gates Ca2+ channels
location: plasma membrane of nerve terminal
function: to stimulate NT release
give the location and function of acetylcholine receptors
location: plasma membrane of muscle cell
function: excitatory synaptic signaling
give the location and function of GABA receptors
location: plasma membrane of many neurons function inhibitory synaptic signaling
give the location and function of stress activated cation channel
location: auditory hair cell in inner ear
function: detection of sound vibratiosn
what are the major classes of channels
voltage gated, ligand gated extracellular, ligand gated intracellular, and stress activated
what are ABC transporters
integral membrane proteins responsible for ATP powered translocation of many molecules
how many domains are on an ABC transporter and what are they
4 domains, 2 hydrophobic, 2 ATP binding
explain receptor mediated endocytosis of LDL
LDL binds to its receptor, it is transported through the cell by a clatharin coated vesicle where it binds to an endosome that then transfers to a lysosome and LDL is degraded into free cholesterol and the receptor buds off the endosome in a vesicle that is then recycled back to the plasma membrane
