BIOLOGY 1A03 Lecture Notes - Lecture 1: Lipid Bilayer, Respiratory Tract, Bacterial Capsule

• School: McMaster University
• Department: Biology
• Course: BIOLOGY 1A03
• Professor: Rosa Da Silva

Document Summary

Therefore, bilayers form closed structure with closed inner space: note: organization explains why membranes are self healing. Large polar and charged molecules: require protein channels (integral: slide 26-36: transport of substance across membrane membrane proteins, passive or simple diffusion: Involves movement of small molecules in direction of concentration gradient. Isotonic environment: water concentration is same inside/outside cell, there is no net movement of water and the cell can retain its shape and optimal cellular activities. Beneficial for both animal and plant cell: e. g. red blood cells in isotonic solution retain their concave , disk-like shapes, hypotonic environment: low concentration of solute outside cell and high concentration of solute inside. Excessive movement of water inside cell down concentration gradient leads to cell swelling or bursting ghost cells. Bad for both animals and plant: e. g. red blood cells in hypertonic solution have lower solute conc. than solution and will shrink due water loss, active transport, movement of molecules against concentration gradient.