BIO 111 Lecture Notes - Lecture 7: Enthalpy, Electronegativity, Exocytosis
Document Summary
Atp used to move substances against their gradient. Diffusion - net movement of molecules down concentration gradient. Most substances want to spread out. (to be less crowded) Some substances diffuse more readily than others. Relatively constant internal environment different from their external environment. Both an electrical gradient and chemical gradient. Movement of water across a selectively permeable membrane. Water can cross, but solute can not. Net water movement: toward lower water concentration (higher solute concentration) Based on relative solute and water concentrations. Side a is __hypertonic compared_____ to side b . The inside of the fish is _hypertonic____ to the surrounding lake water. Turgor pressure pushes plasma membrane against cell wall. Plasmolysis plants wilt, water leaves cells. Bacteria release toxin that cause chloride and sodium ions to be released into the gut. Remember, not everything diffuses through the plasma membrane . Passage for the direct diffusion across the membrane. Couples conformational changes to an energy source.
