Bios 208 1st Edition Lecture 9 Outline of Last Lecture I. AminoII. SulfhydrylIII. PhosphateIV. Phosphate group significanceV. MethylVI. Biological PolymersVII. CarbohydratesOutline of Current Lecture I. Glycosidic linkagesII. Cellulose digestionIII. ChitinIV. LipidsV. Fats and OilsVI. The structure of a phospholipidCurrent LectureI. Glycosidic linkagesA. Only the ring form can make glycosidic linkages with other monosaccharides.B. Hydroxyl groups attached to specific carbons form these linkages.C. Glycosidic linkages covalently join monosaccharides to make disaccharides (an example of dehydration synthesis).e.g. Sucrose sugar is formed from fructose and glucose.D. Sucrose…a great carbohydrate.II. Cellulose digestionA. Cellulose is a major structural component of plant cell walls (wood, paper). Provides strength. It contains a lot of energy (can be burned), but is not used of energy storage in cells because it is very difficult to degrade.B. Flat ribbons are held together by H-bonds; bundles are micro fibrils.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.C. Enzymes capable of degrading cellulose are rare in nature. These enzymes occur in microorganisms that live in the guts of cows and termites, allowing these organisms to get energy from cellulose.D. Carbohydrate polymers:a) Monosaccharides are added one-at-a-time; joined by glycosidic linkages.b) They can have 1000’s of subunits.c) They can be branched.d) They can be made from one type or several types of monosaccharide.e) “Starch” is used for energy storage (amylose and amylopectin occur in plant chloroplasts; glycogen is found in animal liver cells).A. Starch:a) Contains only glucose.b) Joined by 1, 4 linkages.c) Can be branched or unbranched.d) Coiled and hydrated in aqueous solution.III. Chitin B. Chitin, another structural polysaccharide, is found in the exoskeleton of arthropods.C. Chitin also provides structural support for the cell walls of many fungi.D. It is used to make dissolving surgical thread.E.IV. LipidsA. Contain many C-C and C-H bonds.B. Hydrophobic.C. Store lots of energy in these bonds.D. Large molecules, but NOT polymers.E. There are many types.a) Triglycerides: fats and oils (energy storage).b) Phospholipids: bilayer membranes.c) Steroids: membranes; hormones.V. Fats and OilsA. Fat synthesis involves a dehydration reaction. A fatty acid (chain of 16-20 C’s) is joined byits carboxyl group to glycerol.B. The bond formed is an ester linkage.C. Fat molecule (triacylglycerol, triglyceride, or TG). Three fatty acids are attached to one glycerol by ester linkages.D. Hard fats from animals (butter, lard, bacon grease) are solid at room temperature (~25ºC) due to tight packing of saturated fatty acids.E. Oils from plants (olive oil, corn oil) are liquid at RT due to cis.F. Double bonds in unsaturated fatty acids, such bonds cause bends or kinks, which prevents solidification.VI. The structure of a phospholipidA. Phospholipid molecule:a) 2 fatty acid tails;b) glycerol;B. Hydrophilic head group: –a) chg. phosphate and a +b) chg. Group. c) Molecules are amphipathic, i.e., one end is hydrophobic and the other is hydrophilic.C. In water, phospholipids spontaneously assemble into lipid bilayers. Hydrophilic heads interact with water. Hydrophobic tails avoid water and interact with each other. Lipid bilayers are the basis of all biological
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