Membrane Transport II

Flashcards covering key concepts in membrane transport, including processes, transport mechanisms, and specific transport proteins.

Passive Diffusion

Movement of molecules across a membrane without the use of energy, following the concentration gradient.

Carrier-Mediated Transport

Transport of substances across a membrane via specific binding sites on carrier proteins, can be passive or active.

Active Transport

Movement of molecules against their concentration gradient, requiring energy, often through ATP hydrolysis.

Exocytosis

Process by which cells expel materials in vesicles that fuse with the plasma membrane.

Endocytosis

Process by which cells engulf substances from the extracellular environment into vesicles.

SGLT1

Sodium-dependent glucose transporter that uses the sodium gradient to facilitate glucose uptake into cells.

Symporter

A type of transporter that moves two or more solutes in the same direction across a membrane.

Antiporter

A type of transporter that moves two or more solutes in opposite directions across a membrane.

Fick’s Law

Formula used to describe diffusion of a substance across a membrane; JX = PX * [X] (flux is proportional to permeability and concentration gradient).

Concentration Gradient

Difference in concentration of a substance across a space or membrane, driving the movement of molecules.

Phagocytosis

Endocytic process where cells engulf solid particles, often used by immune cells to capture pathogens.

Pinocytosis

Endocytic process where cells take up liquid and soluble molecules from the extracellular fluid.

Ligand-Gated Channels

Channels that open or close in response to the binding of a specific ligand.

Voltage-Gated Channels

Channels that open or close in response to changes in membrane potential.

Conformational Change

A change in the structure of a protein, often involved in the mechanism of transporters.

Na+/K+ Pump (Na+-K+-ATPase)

An active transport mechanism that pumps sodium out and potassium into the cell against their concentration gradients.

ATP-Binding Cassette Transporters

A large family of transporters that utilize ATP hydrolysis to transport various molecules.

Solute

A substance that is dissolved in a solvent, forming a solution.

Saturation Kinetics

A situation in transport where all carriers are occupied, limiting transport rate despite increasing substrate concentration.

Electrogenic Pump

A pump that contributes to the membrane potential due to the unequal pumping of ions.