Diffusion Across the Plasma Membrane

Definition

This is a process where molecules move from an area of high concentration to an area of low concentration across a cell's plasma membrane. It's a type of passive transport, meaning it doesn't require energy.

Related terms

Osmosis:

This is a specific type of diffusion involving water molecules. Water moves from areas of low solute concentration to areas of high solute concentration across a semi-permeable membrane.

Active Transport:

Unlike diffusion, this process requires energy because substances are moved against their concentration gradient – from an area of low concentration to one of high concentration.

Semi-Permeable Membrane: A barrier that allows certain substances to pass through while blocking others. The plasma membrane is semi-permeable, allowing for processes like diffusion and osmosis.