lecture 3-4

lecture 3-4 - 17:46 What's a good way to study for exams? I...

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17:46 What’s a good way to study for exams? I learned a lot of the concepts ahead of time because I studied over winter break up till chapter 13. I was thinking about doing the problems after each chapter, but are they useful? Mastering biology: card in back of book Lecture quizzes on blackboard this Friday, due on Wednesday 6 am Carbohydrates Monosaccharides, particularly glucose = major fuel for cellular work Also raw material for synthesis of other monomers: amino acids, fatty acids Almost always cyclize to form rings Anomeric carbon = always a carbon atom involved in bonds Two possible ring structures for glucose: Alpha, beta These differ in orientation of the hydroxyl group attached to C1. Alpha more stable than beta Disaccharides: glycosidic linkage, formed by dehydration: anomeric carbon + OH group Maltose (malt sugar, a homodimer) is formed by joining 2 glucose molecules Sucrose (table sugar, a heterodimer) is formed by joining glucose and fructose, 2 anomeric carbons stuck together Polysaccharide Starch: in plants, polysaccharide of α-glucose monomers = storage
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α1-4, α1-6 Glycogen: in animals, store excess energy, looks a lot like amylopectin, but is more heavily branched Cellulose: in plants, uses β-glycosidic linkages Different from α-glycosidic linkages Few animals can digest and get energy from it Cows Fungi Lipids Strongly hydrophobic because of large numbers of non-polar C-H bonds. There are few C-O bonds to impart polarity Fuels – efficient source of energy for cells. Breaking down lipids twice as much energy as an equivalent mass of carbs Broken down slowly, energy in C-H bonds is transferred to other smaller molecules for use in the cell Energy stores: animals can store energy lipids in special cells (adipocytes) Structural: special types of lipids (phospholipids, steroids) are integral components of cell membranes Monomers: Macromolecules (polymers) Glycerol and fatty acids = triglycerides Ester linkage, glycerol, 3 fatty acids Adypocytes Triacylglycerol 3 Hydrocarbon chain, each bound at one end to glycerol Almost perfectly insoluble in water Can’t go through bloodstream
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Ester linkages Saturated fat Stearic acid Every carbon has hydrogen atoms Solid at room temperature butter Unsaturated fat Oleic acid Oil Double bonds cause bending Liquid at room temperature No trans-double bonds in animals Bad for us! Bacteria make trans-fats to kill organisms that eat it Cis-double bonds Phospholipids Phosphotidylcholine—major component in cell membranes in all biological organisms Hydrophilic head—loves water :D Choline (positive charge, very polar) Phosphate Glycerol
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Hydrophobic tail—hate water! >_< Fatty acids amphoteric—having both hydrophilic and hydrophobic characters Cholesterol, a steroid Most common, found in all animal membranes (not in plants) Sex hormones Estradiol (female) Testosterone (male) In Burmese pythons, heart size increases after feeding as a result of increases in:
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This note was uploaded on 03/14/2012 for the course BISC 13141 taught by Professor Williammcclure during the Spring '10 term at USC.

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lecture 3-4 - 17:46 What's a good way to study for exams? I...

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