Membrane Transport

Vocabulary flashcards summarizing key concepts related to membrane transport in cell biology.

Membrane transport

The process by which substances move across a cell membrane through various mechanisms.

Active transport

The movement of molecules against their concentration gradient, requiring energy, usually in the form of ATP.

Passive transport

The movement of molecules down their concentration gradient without the use of energy.

Transporters

Proteins that facilitate the movement of substances across cell membranes.

Concentration gradient

The difference in concentration of a substance across a space.

Ion channels

Proteins that create passageways for specific ions to move across membranes, typically via passive transport.

Aquaporins

Channel proteins that facilitate the passive transport of water.

Electrochemical gradient

The combined gradient of concentration and electrical potential that affects ion movement across a membrane.

Symporter

A transporter that moves two or more different molecules in the same direction across the membrane.

Uniporter

A transporter that moves a single molecule across the membrane.

Phosphorylation

The addition of a phosphate group to a molecule, often used in the regulation of enzymes and transporters.

Glucose transporter

A type of transporter that facilitates the movement of glucose across the plasma membrane.

Osmosis

The movement of water across a semi-permeable membrane from an area of lower solute concentration to an area of higher solute concentration.

Na+ pump

A type of active transporter that moves sodium ions out of a cell and potassium ions into a cell against their respective gradients.

Porins

Proteins that form channels in bacterial outer membranes, allowing passive diffusion of small molecules.

Membrane potential

The voltage difference across a cell membrane, created by the distribution of ions.

Contractile vacuole

An organelle that collects excess water and expels it from the cell to regulate osmotic pressure.