The polysaccharide cellulose is a major component of

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The polysaccharide cellulose is a major component of the toughwall of plant cellsb.Like starch, cellulose is a polymer of glucose, but the glycosidiclinkages differc.The difference is based on two ring forms for glucose: alpha (α)and beta (β)d.Structure function relationships1.Polymers withαglucose are helical2.Polymers withβglucose are straighte.In straight structures, cellulose, H atoms on one strand can bondwith OH groups on other strandsf.Parallel cellulose molecules held together this way are groupedinto microfibrils, which form strong building materials for plantsg.Enzymes that digest starch by hydrolyzingαlinkages can’thydrolyzeβlinkages in celluloseh.Cellulose in human food passes through the digestive tract asinsoluble fiberi.Some microbes use enzymes to digest cellulose
Biological Science ITue/Thr 11:00-12:15pm, Fisher Lecture HallBSC 2010Dr. Charrel-Dennis18j.Many herbivores, from cows to termites, have symbioticrelationships with these microbesb.Chitina.Chitin, another structural polysaccharide, is found in theexoskeleton of arthropodsb.Chitin also provides structural support for the cell walls of manyfungic.Used to make “dissolving stitches”LIPIDSShare one important trait: mix poorly with waterAre not true polymeric macromoleculesSome polar parts, but generally hydrocarbons (non-polar)We will focus on Fats, Phospholipids and Steroids1.Fatsa.Fats are constructed from two types of smaller molecules: glycerol and fatty acidsi.Fatty acids1.Think about the name fatty acid (Hydrocarbon + Carboxyllic acid)2.A fatty acid consists of a carboxyl group attached to a long carbonskeletonii.Glycerol1.three-carbon alcohol with a hydroxyl group attached to each carboniii.Three fatty acids are joined to glycerol by an ester linkage, creating atriacylglycerol, or triglycerideiv.Fatty acids vary in1.length (number of carbons)2.number and locations of double bondsa.Saturated fatty acidsi.have the maximum number of hydrogen atoms possible andno double bonds (They are saturated with hydrogens)ii.solids at room temperatureiii.animal fats (except for fish)b.Unsaturated fatty acidsi.have one or more double bondsii.liquids at room temperatureiii.plant and fish fatsb.Some points on hydrogenationi.A diet rich in saturated fats may contribute to cardiovascular disease throughplaque depositsii.Hydrogenation is the process of converting unsaturated fats to saturated fatsby adding hydrogen
Biological Science ITue/Thr 11:00-12:15pm, Fisher Lecture HallBSC 2010Dr. Charrel-Dennis19iii.Hydrogenating vegetable oils also creates unsaturated fats with trans doublebondsiv.These trans fats may contribute more than saturated fats to cardiovasculardiseasec.Functions in biologyi.The major function of fats is energy storage1.A gram of fat stores twice as much energy as a gram of carbohydrate(Remember my gasoline analogy last Thursday??)2.Plants don’t have to move so they can store carbohydrates,animalsmove so need a more efficient energy storage solution.ii.

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Term
Spring
Professor
Pf
Tags
Biology, DNA, Atom, Chemical bond, Dr Charrel Dennis

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