BLG 311 Lecture 7: Cell bio section 3 notes
5 Mar 2018
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Key membrane functions: plasma membrane separates and maintains the living properties of the cell: defines the cell. Internal membranes compartmentalize the eukaryotic cell forms organelles: maintains ion and chemical gradients, controls material exchange between the cell and its environment, senses and controls communication between cells, malleable: able to change shape. Note: flow of ion depends on concentration- important for exchange between interior and exterior of cell. Biologically membranes are generally composed by lipids and proteins. Note: what separates inside and outside of cell is a lipid bilayer 2 layers facing each other. Layer 1 and layer 2 can also be called leaflets (leaflet 1 and leaflet 2) Nucleus and mitochondria have a double lipid bilayers, the rest of the organelles have a single lipid bilayer. The main membrane lipids are: phospholipids, gylcerophospholipids: uses glycerol for backbone and phosphate group, sphingophospholipids: uses sphingosine for backbone, phosphate group, sterols- cholestrol, 30% plasma membrane made up of sterol, others function in hormones.
