Absorbing minerals
Plants can only absorb soluble minerals (those that can dissolve in water). They absorb minerals dissolved in solution from the soil through their A specialised cell that increases the surface area of the root epidermis to improve the uptake of water and minerals.. However, the concentration of minerals in the soil is very low.
Active transport – Higher tier only
Minerals cannot be absorbed by osmosis because this is the movement of water only. They cannot be absorbed by The movement of molecules from an area of higher concentration to an area of lower concentration., because the minerals are in very low concentration. Instead, active transport is used.
The root hair cells have carrier proteins in their cell membranes. These pick up the mineral ions and move them across the membrane into the cell against the The difference in concentration between two solutions, between different cells or between cells and a surrounding solution..
Because active transport moves ions against the concentration gradient into the root hair cells, energy is needed. The energy is supplied in the form of ATP (adenosine triphosphate).