FINAL EXAM Chapter 2 Be able to explain the relationship of the orbitals to the potential energy of electrons and the significance of unfilled shells When atoms have filled shells are more stable and less reactive o Noble gases Electrons with least amount of PE are located in K shell closest to the nucleus electrons with MORE PE are located in shells farther from the nucleus At higher energy levels more electrons are contained o May contain more orbitals however outer shells have a max of four orbitals and eight electrons Be able to distinguish between covalent and ionic bonds Covalent bond pairs of electrons shared by two atoms o Depends on electronegativity Ionic bond when two atoms differ considerably in their electronegativity o NaCl o One of atoms will lose electron to the other atom Positively charged ion cation and negatively charged ion anion Stronger than covalent bonds Be able to distinguish polar and non polar bonds Non polar covalent bond electrons are shared equally o CH4 Polar covalent bond electrons are shared unequally o Partial charges created in the molecule o H2O Weak bonds do not involve exchange or sharing of electrons o Hydrogen bond Chapter 3 Be able to describe the four properties of water that make it useful for life Cohesive behavior Ability to moderate temperature o Water absorbs heat from warmer air and releases stored heat to cooler air High specific heat can absorb or release a large amount of heat with only a slight change in its own temperature Heat absorbed when hydrogen bonds break and released when hydrogen bonds form Expansion upon freezing point Minimizes temp fluctuations o Hydrogen bonds in ice are more ordered making ice less dense Versatility as a solvent o Due to its polarity which allows it to form hydrogen bonds easily o When an ionic compound is dissolved in water each ion is surrounded by a sphere of water called a hydration shell o Most reactions occur in water Chemical reactions depend on collisions of molecules and therefore on concentration of solutes in an aqueous solution Be able to explain how the polar structure of water molecules results in hydrogen bonds Water has two covalent bonds o O with 2 H s partial negative charge o Molecules held together by hydrogen bonds o Responsible for 4 characteristics Water is a polar molecule o Opposite ends have opposite charges o Polarity allows water molecules to form hydrogen bonds with each other Be able to explain the relationships between molecular mass Avogadro s number and molarity and be able calculate molarity from mass and the reverse M m v Molecular mass sum of all masses of all atoms in a molecule o 1 mole 6 02e23 molecules Avogadro s number 6 02e23 Daltons 1 g Chapter 4 Be able to identify the major functional groups found in organic molecules Functional groups components of organic molecules that are most commonly involved in chemical reactions o Number and arrangement of functional groups give each molecule its unique properties Hydroxyl o OH o Alcohols names usually end in ol Carbonyl Carboxyl o Ketones if the carbonyl group is within a carbon skeleton o Aldehydes if the carbonyl group is at the end of the carbon skeleton o C O o Carboxylic acids or organic acids o Act as acid OH C O Amino o Amines o Act as base N H Sulfhydrl o Thiols o SH o Stabilizes protein structure Phosphate Methyl o Potential to react with water releasing energy o Contributes negative charge to the molecule of which it is a part o C 3 H s o Affects expression of genes o Sex hormones Be able to distinguish between mechanism and vitalism and the relevance of these to Stanley Miller s experiments Vitalism idea that organic compounds are distinct from other chemical compounds and could only arise from within a living organism Mechanism all natural phenomena are governed by physical and chemical laws Stanley Miller experiment can organic molecules be formed without a living organism o Abiotic synthesis o Took molecules that were believed to be major components of early earth s atmosphere and put in closed system Methane ammonia hydrogen water Ran electric current through system After one week 15 of carbon was now in form of organic compounds o SUPPORTED MECHANISM o Showed that organic compounds such as amino acids which are essential to cellular life could be made easily under conditions that were present on early earth Chapter 5 Know that the four major types of biological molecules are carbohydrates lipids proteins and nucleic acids Be able to distinguish between hydrolysis and dehydration reactions and explain their roles in forming polymers Polymer long molecule consisting of many similar building blocks o Small building blocks called monomers o Polymers Polysaccharides proteins nucleic acids o Non polymer lipids Dehydration reactions occurs when two monomers bond together through the loss of a water molecule o Synthesizes polymers Hydrolysis Polymers disassembled to monomers o Reverse of dehydration reaction Be able to distinguish among lipids carbohydrates and proteins based on chemical structure e g proteins are chains of amino acids etc Polypeptides unbranched polymers built from same set of 20 amino acids Lipids o Protein consists of one or more polypeptides o Amino acids Organic molecules with carboxyl and amino groups 20 different ones Make up proteins R Groups Differ in properties due to differing side chains o DO NOT form polymers o Little or no affinity for water o Hydrophobic because consist of mostly hydrocarbons FATS PHOSPHOLIPIDS AND STEROIDS o Fats Glycerol and fatty acid Glycerol three carbon alcohol with hydroxyl group attached to each carbon Fatty acid carboxyl group attached to long carbon skeleton Joined by ester linkage Saturated fatty acid max number of hydrogen atoms possible and no double bonds Unsaturated fatty acids one or more double bonds Solid at room temp Liquid at room temp Phospholipid Two fatty acids and a phosphate group attached to a glycerol Fatty acid tails hydrophobic Phosphate group hydrophilic Carbohydrates o Include sugars and the polymers of sugars o Monosaccharide s simple sugars Monomers Classified by location of carbonyl group and number of carbons Polymers formed by joining together monomers in a chain on carbon skeleton o Polysaccharides Glycosidic linkage Starch o Sugars glucose o Polymers with alpha glucose are helical Amylose and glycogen o Polymers with beta glucose are straight Cellulose Microfibrils strong building materials for plants Chitin
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