In plants, water and mineral salts absorbed by the roots reach all parts through the xylem, and food made by the leaves is carried through the phloem. The bulk movement of substances through the vascular tissue is called Translocation. In animals, the circulatory system – blood and lymph, the heart and blood vessels – transports nutrients, salts, oxygen, hormones and waste products.
1. Means of Transport in Plants
| Process | What happens | Energy |
|---|---|---|
| Diffusion | Molecules move from higher to lower concentration | Not used – passive |
| Active transport | Molecules pumped against a concentration gradient ('uphill' transport) by membrane bound proteins called pumps | Used |
| Osmosis | Solvent or water molecules move from higher to lower concentration through a semi-permeable membrane until equilibrium | Passive |