Biology 1202B Lecture Notes - Lecture 3: Phosphatase, Phagocytosis, Cell Membrane
20 Apr 2016
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Document Summary
Passive transport is limited to movement down a concentration gradient. Many cellular processes require molecules to be present at a high concentration: active transport can move molecules against a concentration gradient (low to high, this action requires the input of energy. 25% of a cells atp resources used in actively transporting molecules. 3 main functions: lower in cells outside the cells: primary active transport. Movement of ions, glucose, amino acids against gradient. Atp hydrolysis alters conformation of transport protein (directly use atp) Membrane potential- movement of ions across the membrane creates an electrical potential difference (charge inside is negative vs. the outside) Inside cell vs. outside of cell o: electrochemical gradient- na+/k+ pump, secondary active transport. Electrochemical gradient from primary used to drive secondary. The transfer of the solute across the membrane is always coupled with the transfer of an ion supplying the driving force. Sometimes molecules are too big to move through a trans membrane protein (use exo/endocytosis)
