BIOM1050 Lecture Notes - Lecture 8: Cholesterol, Viscosity, Tonicity
Document Summary
Module 1 - a study of life and. The fluid mosaic model - membrane is fluid with a mosaic of proteins embedded in it. Cholesterol helps with the viscosity of the membrane. Lipid bi layers are impermeable to most essential molecules and ions. Some permeability to water molecules and a few other small, uncharged, molecules like oxygen and carbon dioxide. Ions such as k+, na+, ca2+, cl-, hco3- Passive transpost is diffusion of a substance across a. Diffusion with time- due to random motion molecules become equally distributed i. e. to eliminate concentration gradients - provided molecules can cross the membrane. Diffusion across a biological membrane is passive transport (no atp requires) Diffusion of water through a selectively permeable membrane into another aqueous compartment containing solute at a higher concentration. What are osmotica (things that are osmotically active) Tonicity is the ability od a solution to cause a cell to gain or lose water.
