PHGY 209 Lecture Notes - Lecture 19: Active Transport, Phagosome, Caveolae
3 May 2016
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Facilitated diffusion particles always diffuse along their concentration gradient (from higher concentration to lower) Primary active transport : carrier-mediated, requires supply of chemical energy (usually derived form enzymatic hydrolysis of atp, 3. Can transport solute against its concentration gradient (i. e. , uphill transport ) Cells: (sodium- potassium pump) sodium/ potassium pump looks like : Active transport in which energy released during transmembrane movement of one substance from higher to lower concentration is transferred to the simultaneous movement of another substance from lower to higher concentration. The above process is called cotransport because na+ moves in the same direction as the solute (x). A solute can also be transported in the opposite direction to na+ movement; this is called countertransport. Endocytosis the cell membrane invaginates, forming a channel, the end of which pinches off to form a vesicle. Exocytosis an intracellular vesicle fuses with the cell membrane, and its contents are released into the ecf.
