Passive and Active Transport

The transport of materials across the cell membrane from an area of high concentration to an area of low concentration without the use of energy is called passive transport.

Sometimes proteins are used to carry large molecules across a cell membrane. This process is called facilitated diffusion.

Some substances move across the cell membrane from an area of low concentration to an area of high concentration with the use of energy. The transport of materials through proteins in the cell membrane using energy is called active transport.

An example of active transport is when plant root cells take in minerals from the surrounding soil. Because plant root cells typically have more minerals inside of them than the soil surrounding the roots, they use active transport to take in minerals from the soil.