bio 224 lab Revisions

bio 224 lab Revisions Plasma Membrane and Osmosis Plasma Membrane • Plasma membrane separates cell interior from the outside environment. • Consists of phospholipid bilayer with embedded proteins. • Regulates passage of molecules and ions in and out of the cell. Aquaporin • Integral membrane proteins facilitating water transport across cell membranes. • Control water balance and osmotic pressure. • Found in tissues like kidneys, lungs, and salivary glands. Osmosis • Passive movement of solvent molecules through a semipermeable membrane. • From lower to higher solute concentration regions. • Equalizes solute concentration on both sides of the membrane. Osmotic Solutions • Isotonic: Equal solute concentration inside and outside the cell. • Hypotonic: Lower solute concentration outside the cell, causing cell swelling. • Hypertonic: Higher solute concentration outside the cell, leading to cell shrinkage. Osmoregulation • Physiological process regulating solute and water concentration for homeostasis. • Involves controlling water intake, excretion, and ion concentrations. • Water moves into the cell due to lower osmolality outside. • Cell may swell or burst if water uptake exceeds regulation capacity. Isotonic Extracellular Fluid • No net movement of water, maintaining normal cell shape and size. • Water moves in and out of the cell at equal rates. Hypertonic Extracellular Fluid • Water moves out of the cell due to higher osmolality outside. • Cell shrinks or shrivels to counteract water loss. Physiology of Plasma Membrane in Osmosis Phospholipid Bilayer • Selective permeable barrier allowing water passage. • Restricts movement of larger or charged molecules. Integral Proteins • Includes aquaporins facilitating rapid water movement