Substances (or particles) must move into and out of animal and plant cells for an organism to function. These substances are moved by diffusion, osmosis and active transport.
The properties of these forms of transport, both active and passive, are shown in the table below.
|Description||The movement of substances from a region of high concentration to a region of low concentration.|
Or in other words, the movement of substances down a concentration gradient.
|The movement of water molecules down a concentration gradient and across a partially permeable membrane.||The movement of substances from a region of low concentration to a region of high concentration.|
Or in other words, the movement of substances against a concentration gradient.
|With the concentration gradient||✔️||✔️||❌|
|Against the concentration gradient||❌||❌||✔️|
|Examples of substances moved||Oxygen, carbon dioxide, nutrients (e.g. glucose), waste products (e.g. urea).||Water||Glucose moving from the lumen to the intestinal cells, and mineral ions moving into plant roots.|