Transport Across Membranes

Flashcards covering key concepts related to transport across biological membranes, including definitions of transport methods and specific proteins involved.

Passive diffusion

Movement of molecules across a membrane without the need for energy.

Facilitated diffusion

Process where specific proteins transport solutes down their concentration gradient without energy.

Active transport

Process that requires energy to transport molecules against their concentration gradient.

Osmosis

A special form of passive diffusion involving the movement of water across a semi-permeable membrane.

Endocytosis

The process by which cells take in extracellular material via membrane-bound vesicles.

Exocytosis

The fusion of membrane-bound vesicles with the plasma membrane to secrete proteins and neurotransmitters.

Phagocytosis

A type of endocytosis where the cell engulfs large particles or cells.

Pinocytosis

A type of endocytosis where the cell takes up extracellular fluid with dissolved solutes.

Ion channels

Integral membrane proteins that form pores allowing specific ions to pass through the membrane.

Carrier proteins

Integral membrane proteins that bind specific solutes and facilitate their passage across the membrane.

Sodium-potassium ATPase

An active transport pump that maintains the electrical potential across the plasma membrane by pumping Na+ and K+ ions.

Cotransporter

Transport proteins that couple the movement of one solute down its gradient with the movement of another solute against its gradient.