Diffusion in the Cell

Diffusion in the Cell

The video below describes diffusion as movement of particles from high to low concentration.

Cells have membranes that are selectively permeable, which allow solutes to pass through to reach balanced concentrations. While small, uncharged molecules can pass through the hydrophobic inside of cell membranes, large or charged molecules need transport or channel proteins in order to cross a membrane barrier.

Diffusion does not require energy and is therefore referred to as passive transport. Passive transport can be either simple or facilitated diffusion.

1. Simple Diffusion - movement of molecules down a concentration gradient, without the assistance of channel or transporter proteins

2. Facilitated Diffusion - movement of molecules down a concentration gradient across a membrane, with the assistance of channel or transporter proteins

Reference:

Study.com