BSC 109 1nd Edition Lecture 4Outline of Last Lecture I. Key properties of waterII. IonsIII. The building block of organic moleculesIV. Macromolecules are synthesized and broken down within the cellV. Macromolecules of lifeOutline of Current Lecture I. Polysaccharides store energyII. Lipids: insoluble in waterIII. ProteinsCurrent LectureI. Polysaccharides store energyA. Polysaccharides are thousands of monosaccharides joined in chains and branches1. Starch: made in plants, stores energy (ex: potatoes, rice, corn, pasta)2. Glycogen: made in animals; stores energy, long chains of glucose3. Cellulose: indigestible polysaccharide made in plans for structural supportin cell wallsB. The difference between starch and cellulose1. Different covalent bonds between glucose units2. Starch is digestible, cellulose is notII. Lipids: insoluble in waterA. 3 types1. Triglycerides: energy storage molecules2. Phospholipids: cell membrane structurea) StructureThese 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.(1) Glycerol + 2 fatty acids and a phosphate(2) Hydrophilic head(3) Hydrophobic tailb) Function: primary component of cell membranes3. Steroids: carbon-based ring structuresa) Composed of 4 carbon ringsb) Ex: cholesterol, hormones (estrogen, testosterone)c) Some steroids (anabolic) are highly controversial(1) Abused by some athletes(2) Can be helpful for children seeking HGH effects(3) Side effects: acne, enlarged sex organs impotency, deepened voice, unusual hair growth/loss, psychological disturbances, enlarged breasts in malesB. Composed of glycerol and 3 fatty acids1. Saturated in fats (solid at room temperature)2. Unsaturated in oils (liquid at room temperature)3. Stored in adipose tissue4. Shape and length of tail can vary5. Saturated have maximum number of hydrogen bonds6. Unsaturated has a double bondC. Trans fats1. Hydrogenation of unsaturated oils2. Converts to saturated fat3. Intended to be healthier and prolong shelf life: detrimental to healthIII. ProteinsA. Long chains (polymers) of amino acids1. 20 different types2. Joined by peptide bonds3. Produced by dehydration synthesisB. Structure determines function1. Primary structure: sequence of amino acids (looks like beads on a string)2. Secondary structure: chains of amino acids (know beta sheet (looks like a fan) and alpha helix (looks like coils))3. Tertiary structure: random 3D shapes4. Quaternary structure: varies in number of polypeptide chains and their associations5. Denaturization: permanent disruption of protein structure (like a cooked egg)a) Loss of biological function (ex: sickle cell)b) Prions: infections proteins that can become improperly folded(1) Same amino acid form as normal sequences(2) Shapes are radically different(3) Change in shape means change in function(4) Ex: Mad cow disease, Scrapie, Creutzfeldt Jakob disease(5) All are fatalC. Enzymes1. Biological catalysts: speed up chemical reactions but are not altered or consumed2. Help maintain homeostasis3. Functional shape of an enzyme is dependent on environment4. Malnutrition: lacking in some key nutrient, usually
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