KP222 Lecture 3: KP222 Lecture 3
18 Jan 2019
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Caused by unequal distribution of anions and cations across the cell membrane. At rest, the inside of a cell is more negative than outside. Direction of force depends on two factors. Body is neutral (cation=anions) by not so for icf and ecf. Icf has more anions (-ve) and ecf has more cations (+ve) Magnitude of force depends on two factors. Sum of chemical and electrical forces=total force. If they act in the same direction. Magnitude=sum of the chemical force and the electrical force. Question: if a chemical gradient existed, under which conditions would a particle not be transported across a membrane even if it is permeable to that particle. Answer: when the electrical force is equal to, but opposite in direction to , the chemical force. To determine which force is larger, we need an ions equilibrium potential. Electrical force and chemical force act in opposite directions.
