Cell to Cell Transport

Cell-to-cell transport, also called short-distance transport, covers only a small area and a handful of cells at a time - moving a substance, say, from one root-hair cell to its immediate neighbour. On its own this short-range movement cannot supply a whole plant, so it acts as a feeder or tributary system into the long-distance transport carried out over much greater distances by the xylem and phloem. Just like transport in general, the driving force behind cell-to-cell transport can be either passive (diffusion and facilitated diffusion, needing no energy) or active (pumps, needing ATP), and these different mechanisms differ systematically in whether they need a membrane protein, whether they are selective for particular molecules, whether they can be saturate …