Cell Transport: The Basics
Your cells are constantly moving substances around, and simple diffusion is the most basic way this happens. Think of it like a crowded room where people naturally spread out - molecules move from areas of high concentration to low concentration without any energy needed.
This passive process relies on the natural kinetic energy of molecules bouncing around. The rate gets faster with higher temperatures, thinner surfaces, and larger surface areas - just like how heat makes molecules move more quickly.
Facilitated diffusion works similarly but uses special proteins as helpers. Channel proteins act like selective doorways for ions, whilst carrier proteins change shape to transport larger molecules across the cell membrane.
Key Point: Both simple and facilitated diffusion are passive - they don't require energy from the cell!
