Someone explain co-transport, active transport??Watch
*do channel proteins only allow water soluble substances through?
facilitated diffusion is the movement of solutes down a concentraion gradient using transport proteins
Active transport is the movement of solutes against a concentration gradient using carrier proteins ONLY and ATP
Co-transport is the movement of 1 solute against its concetration gradient by transporting another solute down its own concentration gradient. We only need to know the co-transport of Na+ and glucose, but here's a brief summary:
- NA+ is actively transported from epithelial cells into the blood
- there's a lower concentration gradient in the cells than the lumen, so Na+ moves from the lumen into the epithelial cells by facilitated diffusion
- As Na+ is being transported down its concentration gradient, glucose is moved against its own concentration gradient
- There's a higher concentration of glucose in epithelial cells than the blood, so glucose moves by facilitated diffusion.
If there's anything in prarticular you don't understand, feel free to ask.