HUMB1000 Lecture Notes - Lecture 5: Weak Solution, Semipermeable Membrane, Osmotic Concentration
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All molecules are in a state of random motion (kinetic energy) Solute: dissolved substances in a solution (glucose, sucrose, ions [molecule with a charge]na, Solution: mixture formed when solute dissolved in solvent. Diffusion: process where molecules move from an area of higher concentration to an area of lower concentration, continues until the molecules have evenly distributed themselves throughout the solution. 1. certain specific non-lipid soluble molecules or irons diffuse through membrane channels: other non-lipid soluble molecules, for which membrane channels are not present, can"t enter the cell, lipid soluble molecules diffuse directly though the plasma membrane. Facilitated diffusion: move large, water soluble molecules or electrically charged molecules across the plasma membrane, amino acids and glucose in, manufactured proteins out, passive (no energy required) Osmosis: osmolarity is the water pulling power, osmosis is the diffusion of water across a selectively permeable membrane, a spm lets water pass through.