Membrane Transport and Cell Biology

Vocabulary flashcards based on lecture notes covering membrane transport mechanisms, carrier proteins, directional transport types, diffusion, and active transport.

Polarity

A spectrum of molecular charge distribution; nonpolar molecules sometimes cross the cell membrane freely.

Size (Membrane Permeability)

A factor determining membrane passage where small molecules sometimes cross freely.

Carrier

A membrane transport mechanism where a molecule must fit the right shape to function as a ligand.

Uniport

A transporter that moves one molecule or ion across the membrane.

Symport

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

Antiport

A transporter that moves two molecules in opposite directions across the membrane.

Diffusion

A passive, unrestricted mode of transport across a membrane.

Active Transport

A type of transport that requires energy to move substances from low concentration to high concentration.

Energy (in Active Transport)

Energy derived from chemical bonds, specifically phosphate bonds in molecules like ATP.