Page 19 - 02 Cells Biology Notes
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The importance of active transport: energy-consuming process by which
substances are transported against a concentration gradient, e.g. ion uptake
by root hairs and glucose uptake by epithelial cells of villi.
Two big differences between diffusion and active transport:
• direction of movement (down or up a gradient)
• use of energy for movement
The active transport is carried out by ‘carrier proteins’ in the membrane,
which bind to the solute molecule, change shape and carry the molecule
across the membrane.
