Diffusion (AQA A-Level Biology): Flashcards

Passive transport: net movement down concentration gradient, no ATP needed

Energy from particle motion, not from cellular sources

Net movement from high to low concentration until even spread

Difference in concentration between two areas

Small, non-polar molecules like $O_2$ and $CO_2$

Passive transport using proteins for polar/charged molecules

Water-filled pathways selective for specific ions

Proteins that change shape to transport molecules across membrane

Simple: no proteins; Facilitated: requires membrane proteins

Steeper gradient, higher temp, larger area, smaller molecules