BIOL201 Lecture Notes - Lecture 10: Plasmolysis, Electric Field, Gas Constant
22 Jan 2016
School
Department
Course
Professor
Document Summary
The lipid bilayer membrane acts as a barrier that keep cellular contents and organelle contents separate from surrounding medium. But cells need a constant flux of appropriate compounds into the cytoplasm and out of the cytoplasm to maintain structure and generate energy. Therefore, cell have evolved mechanisms for selectively allowing specific kinds of molecules to pass through specific membranes. At the end you have a negative delta g (free energy). Active transport: go up the electrochemical gradient: delta g is +. It will saturate (limit on how much things can pass, the carrier has a limiting capacity). You can target any of the mechanisms with many drugs and toxins: block the protein, block the process. All live cells have a voltage membrane potential across the membrane. No charged molecules, then this won"t sense an electric field. Log of the inverse of a fraction is the negative of the log of the fraction itself (sign change).
