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Biochemistry
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Compounds Compounds are made up of atoms of two more elements in fixed proportions Held together by chemical bonds Covalent Ionic
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Covalent Bond Forms when two atoms share one or more pairs of electrons Example: Carbon Dioxide (CO 2 )
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Ionic Bonds One atom loses electrons while the other atom gains electrons Example: Sodium Chloride (NaCl)
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Oxidation Reduction Reactions Oxidation Reactions- A reactants loses one or more electrons, becomes positive Undergoes oxidation Reduction Reaction- reactant gains one or more electrons, becomes negative Undergoes reduction **Always occur together!
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Importance of Water
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Water One of the most important compounds in living organisms Means of transport Water makes up 70% of most organisms The world is 70% water
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Polarity Water is a polar compound Charges are unevenly distributed Oxygen pulls slightly on the electrons giving it a slightly negative charge Meanwhile, the hydrogen atoms are slightly positive
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Hydrogen Bonding Hydrogen bond- force of attraction between a hydrogen molecule of a partial positive charge and another atom with a negative charge Allows water to easily bond with itself Form, break and reform easily with each other
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Adhesion and Cohesion Adhesion Attractive force between water and a different substance Allows water to stick to other surfaces Capillary action- water can rise up a tube against the force of gravity Cohesion Attractive force between water molecules Allows water molecules to stick to other water molecules Surface tension- molecules of the surface pull downward Acts like a “skin”
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Carbon Compounds
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Organic compounds are made primarily from carbon Bonds readily because Has 4 valance electrons Bonds easily with other carbon Forms straight chains, branched chains, or rings Enormous variety of compounds
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Carbon Compounds Functional groups influence the characteristics of molecules Cluster of atoms at one end Table 3.1 on page 52 highlights these groups
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Carbon Molecules Monomers- single unit of a carbon compound Polymers- repeated, linked monomers bonded together Macromolecules- made up of many large polymers
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Condensation and Hydrolysis Reactions Condensation Linking monomers to create polymers Each time you add a monomer water is released Hydrolysis Breaking down of polymers to monomers Water is used to break the bond
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Molecules of Life
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Carbohydrates Composed of carbon, hydrogen and oxygen 1:2:1 ratio Source of energy Exist as monosaccharides, disaccharides, and polysaccharides
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Monosaccharides Monomer of carbohydrate Also called a simple sugar Most common Glucose Fructose Galactose
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Monosaccharides Glucose, fructose and galactose all have same molecular formula C 6 H 12 O 6 Have different structures These different structures give each slightly different properties Called isomers
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Disaccharides Two monosaccharides combine Also called a double sugar Example: sucrose
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Polysaccharides Complex molecule composed of three or more monosaccharides Storage of energy Animals store in the form of glycogen (highly branched chain) Plants store in the form of starch (branched chains and unbranched chains)
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Proteins Composed mainly of carbon, hydrogen, oxygen and nitrogen Formed by linking of monomers called amino acids
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Amino Acids 20 different amino acids Same basic structure Single hydrogen atom Carboxyl group (COOH) Amino group (NH 2 ) R group (difference) Allows for very different shapes of proteins
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Dipeptides and Polypeptides Two amino acids can form a dipeptide through a peptide bond Most often long chains of amino acids bond to form a polypeptide
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Enzymes Act as a catalyst for reactions Most are proteins Very specific to environments If environment changes slightly, enzyme probably won’t work
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Lipids Non-polar Do not dissolve in water Higher ratio of carbon and hydrogen atoms to oxygen atoms Store more energy Include Fatty acids Triglycerides Phospholipids Steroids waxes
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Lipids Fatty Acids Unbranched carbon chains Long carbon chain with a COOH attached at one end One end is polar and one end in non-polar Hydrophillic- “water loving” Hydrophobic- “water fearing” Triglycerides Composed of three molecules of fatty acid joined to one molecule of alcohol glycerol
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Lipids Phospholipids Two fatty acid molecules attached to one molecule of glycerol Have an attached phosphate group Makes up the cell membrane Waxes Long fatty acid chain joined to a long alcohol chain Water-proof Form protective coatings Steroids Four fused carbon rings with different functional groups attached Hormones
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Nucleic Acids Store and transfer important information for the cell Deoxyribonucleic Acid DNA Contains characteristics of the organism and directs cell activities Ribonucleic Acid RNA Stores and transfers information needed to make proteins
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