BIOL 3402 Lecture Notes - Lecture 5: Fluid Mosaic Model, Lipid Bilayer, Fluid Compartments
Document Summary
Cell is simplest structure and functional unit. Cells come from pre-existing cells: mitosis/miosis. Human cells are bigger than bacterial cells: bacteria out number human cells in the body. Cell membrane (around cell: proteins and lipids. Cytoplasm: intracellular fluid (icf, organelles, cytoskeleten actin fillaments. Structure and movement: extracellular fluid (ecf) Cell membrane cont : defines cell boundaries, governs interaction with other cells, controls materials in & out of cell. Selectively permeable membrane, semipermeable: phospholipid bilayer. Hydrophilic phosphate (head) & hyprophobic fatty (2 tail) Amphipatic (bilayer: chemical/electrical gradient, fluid mosaic model, cholesterol gives structure. Membrane proteins: penetrate membrane, transmembrane proteins pass totally through, some drift, some anchored to cytoskeleton, types: Moving molecules across membranes automatically: example: oxygen, based on concentration gradient. Ions don"t passively cross lipid bilayer due to charge: low permeability. Glucose slightly passes bilayer, but not through usually due to large size: low permeability. Water passes easily due to small size: high permeability.
