BIOL 121 Lecture Notes - Lecture 2: Active Transport, Membrane Transport Protein, Facilitated Diffusion
Document Summary
Active transport movies substances against their concentration gradients. Areas of lower concentration to areas of higher concentration. Active transport creates a state of disequilibrium by making concentration differences more pronounced. The energy for active transport comes either directly or indirectly from the high energy phosphate bond of atp. Two types of active transport: primary (direct) active transport, and secondary (indirect) active transport. Primary (direct) active transport the energy to push molecules against their concentration gradient comes directly from atp. Secondary (indirect) active transport uses potential energy stored in the concentration gradient of one molecule to push other molecules against their concentration gradients. All secondary active transport ultimately depends on primary active transport because the concentration gradients that drive secondary transport are created using the energy from atp. Mechanism for both types of active transport appears to be similar to that fro facilitated diffusion.
