NUTRIENT UPTAKE

Nutrient from soil solution, active uptake against a concentration gradient into root cells; Distribution through the phloem;

Uptake of ions across membranes is accomplished by 3 mechanisms: Simple diffusion – normal diffusion between cells; Facilitated diffusion – ions combine with a membrane protein which then facilitates its uptake across the cell membrane; (In both of the above, the partials move down a concentration gradient); Active transport requiring energy to be exerted (respiration): Where the mineral needs to move up a concentration gradient, the ion will combine with a membrane protein referred to as a carrier. The carrier will transport the partial across the membrane. (Most of this activity takes place via the root hairs).

Minerals: Ions – once dissolved in the plant cell sap (water) are transported through the plant in the xylem (up the plant).

Distribution Through the Phloem: Minerals ions once dissolved in the plant cell sap (water) are transported through the plant in the phloem (around the plant); See hand out. `

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