Cell Membrane Transport Mechanisms and Functions

Cell Membrane

Barrier preventing polar molecules from crossing.

Transporters

Membrane proteins facilitating polar molecule transport.

Polar Interior

Region within transporters binding to and transporting polar molecules.

Non-Polar Exterior

Outer part of transporters compatible with membrane core.

Potassium Channel

Transporter specific for K+ ions in cells.

Active Transporters

Proteins using energy to move substances against gradients.

Passive Transporters

Proteins allowing molecules to flow down concentration gradients.

Gated Transporters

Transporters that open/close in response to signals.

Glucose Transporter

Passive transporter regulating glucose flow in liver cells.

Action Potentials

Electrical signals propagated by neurons using transporters.

Sodium Channels

Gated channels allowing Na+ influx during action potentials.

Voltage-Gated Channels

Channels opening in response to membrane voltage changes.

Potassium Channels

Transporters allowing K+ efflux to restore membrane potential.

Primary Active Transporters

Use ATP directly for substance transport.

Secondary Active Transporters

Use gradients from primary transporters for energy.

Na+/K+ Pump

Transports 3 Na+ out and 2 K+ in per ATP.

Sodium Gradient

Higher Na+ concentration outside the cell.

Potassium Gradient

Higher K+ concentration inside the cell.

Na+/Phosphate Pump

Transports phosphate into cells using Na+ gradient.

Concentration Gradient

Difference in concentration across a membrane.

Ligand-Gated Channels

Channels opened by binding of signaling molecules.

Electrical Current

Movement of charge due to ion flow.

Neurotransmitter

Molecule triggering action potentials in neurons.

Membrane Potential

Voltage difference across a cell membrane.

Transport Specificity

Transporters selectively bind specific polar substances.