Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Complex Lipids Sections 13.4-13.8
Document related concepts
Transcript
Complex Lipids Sections 13.413.8 By: Cassie Webb and Alyssa Keifer 13.4 What are the Structures of Complex Lipids? Main components of membranes Classified into two groups Phospholipids Contain an alcohol, 2 fatty acids, and a phosphate group Two types Glycerophospholipids and sphingolipids Glycolipids Complex lipids contain carbohydrates 13.5 What Role Do Lipids Play in the Structure of Membranes? Complex lipids form membranes around body cells and small structures inside the cells (organelles) Unsaturated Fatty Acids Lipid molecules in bilayer contain at least one Prevent tight packing of hydrophobic chains Provides a liquid-like character to membranes Similar effect causes lower melting points than saturated Membranes Separate cells from external environment and provide the transportation for nutrients and waste products into and out of the cells Made of lipid bilayers Two layers of complex lipid molecules arranged tail to tail Hydrophobic Get as far from water as possible Hydrophilic On the surface Membranes cont. Lipid part acts as barrier against movement of ions or polar compounds in or out. Protein molecules located on the surface, partly, or fully in the bilayer Polar compounds transported through protein channels or active transport. Fluid Mosaic Model Allows the passage of nonpolar compounds by diffusion Mosaic: meaning topography of bilayers Fluid: meaning free lateral motion in bilayers making it liquid-like 13.6 What are Glycerophospholipids? Structure similar to fats Membrane components of cells throughout the body Alcohol in it is glycerol Glycerophospholipids Composed of 2 of 3 groups are esterified fatty acids May be any long-chain carboxylic acids with or without double bonds 3rd group is esterified by a phosphate group Esterified to another alcohol Letchin Another name A major component of egg yolk Both polar and nonpolar portions in one molecule good emulsifier Example: mayonnaise Cephalins Similar to letchins Contain different alcohols PI (phosphatidylinositol) The alcohol inositol is bonded to rest of the molecule by phosphate ester bond Fundamental structural parts of membrane In the form of PIP2 serves as a signaling molecule in chemical communication 13.7 What are Sphingolipids? They were discovered in 1874 by Johann Thudichum Named after a monster from Greek mythology the sphinx A creature who devoured all who could not provide the correct answers to the riddles. Properties Alcohol sphingosine A long-chain fatty acid connected to NH₂ Ceramide A combination of a fatty acid and a sphingosine They may use different fatty acids Sphingomyelins They are the most important lipids in the myelin sheaths of the nerve cells. Associated with diseases Example: multiple sclerosis 13.8 What are Glycolipids? Complex lipids that contain carbohydrates and ceramides Cerebrosides are one group They contain a ceramide mono- or oligosaccharide Occur primarily in the brain and nerve synapses Gangliosides are another group Have a more complex carbohydrate structure
