Examples of active transport

Sometimes a cell has to work and use some energy to maintain a proper balance of proteins or calcium. They are worked against a concentration gradient.

Diagram showing a cell maintaining a balance of protein using energy working against concentration gradients

In plants, root hair cells use active transport (requiring energy) to absorb minerals from the soil, even though there are lower concentrations of mineral in the soil than there are in the root hair cell.

Movement of minerals from a high concentration outside to low concentration inside of a root hair cell