Carlson 1 Electrical Components of the PM Flashcards
(21 cards)
Integral membrane proteins
Proteins inserted w/ in membrane
Transmembrane proteins
Integral membrane proteins that pass entirely through membranes
Movement of ions
o Binding to molecule
o Cary across membrane
o Release to other side
Peripheral membrane proteins
o Proteins associated w/ membrane but not invested
Net charge
o Counting the number of (+) to (-) ions along a membrane
Dipoles
o Pare of (+) and (-) across a membrane that produce a net charge
Attractive force
o Holds together the dipoles and the charge between the membrane
o Allows the charge to be stored across the plasma membrane (capacitor)
Capacitor
o An electrical component that stores charge
o Lipid bilayer is a membrane capacitor
Voltage (V)
o Concentration of charge
Current (I)
o Movement of charge
Charge (Q)
o Q=C*V
o Q = units of columns , C = Capacitance Farads or culums/volt
Transmembrane Ion Channel
o Is a conduit for the flow of (+) and (-) ions between inside and outside
Transmembrane Ion Current
o Amount of (+) and (-) charges that flow across per unit time
Resistance
o Ion Channels
o ↑ Wider channels = ↑ more ions flow = ↑ more current = ↓ less resistance
o Regulated by:
density of charge w/ in the channel
Gating regions
o Ion channel resistance is infinite in close state (no ions can pass)
Gating regions
o conformation of protein channel that regulate resistance and ion flow
Voltage = Current x total transmembrane resistance
o V = I x R
Total membrane resistance
o Number of transmembrane channels in an OPEN state
Plasma membrane
o Electrical current & capacitor is parallel to a resistor (transmembrane ion channel)
Voltage gates ion channels
o Activated by charge ( in a voltage across the plasma membrane)
Ligand gated channel
Activated by interaction w/ ligand (specific extracellular molecule)
Second messenger channel
o Intercellular 2nd messengers or ions
