Overview Carbon Compounds and Life Unit One Chapter 3 Carbon and the Molecular Diversity of Life water is the universal medium for Earthly life living organisms made of chemicals based mostly on element CARBON Carbon unparalleled in ability to form large complex varied molecules accounts for variety of biological molecules H O N S P are common ingredients of these compounds Organic Compound a compound containing carbon Almost all organic compounds associated w life contain hydrogen atoms in addition to carbon atoms different species and different individuals within those species are distinguished by their variations in large organic compounds Critically important large molecules of all living things fall into four main classes Carbohydrates Proteins Lipids Nucleic Acids Macromolecules large molecule containing a large of atoms Carbohydrates Proteins Nucleic Acids are Macromolecules 1 key to an atoms chemical characteristics is its electron configuration Concept 3 1 Carbon Atoms can Form Diverse Molecules by Bonding to Four Other Atoms Formation of Bonds with Carbon determines kinds and of bonds atom will form w other atoms Carbon 6 electrons 2 in 1st shell 4 in 2nd shell needs 4 more to fill 2nd shell completes valence by sharing its 4 electrons w other atoms so 8 electrons are present each pair of shared electrons constitutes as a covalent bond usually forms single or double covalent bonds in organic molecules acts as intersection point which a molecule can branch off in as many as 4 directions this versatility of carbon make large complex molecules possible every grouping of a carbon bonded to four other has a tetrahedral shape structural formula representing the molecules as if they re two dimensional shape of molecules determines its function Carbon Dioxide molecule O C O each line represents pair of shared electron CO2 sometimes considered inorganic bc it lacks hydrogen 2 Molecular Diversity Arising from Variation in Carbon Skeletons Carbon chains form skeletons of most organic molecules vary in length straight branched or arranged in close rings some have double bonds which vary in and location atoms of other elements can be bonded to the skeletons at available sites Hyrdrocarbons organic molecules consisting of only carbon and hydrogen H atoms attached to Carbon skeleton wherever electrons are available for covalent bonding Major components of petroleum called fossil fuel bc it consists of partially decomposed organisms Hydrocarbons not present in most living organisms many cells organic molecules have regions consisting of only hydrogen and carbon ex fats have long hydrocarbon tails attached to a nonhydrocarbon component petroleum fat hydrophobic don t dissolve in water bc bonds are nonpolar undergo reactions that release a large amount of energy Petroleum gas car fuel Fats animals stored energy 3 The Chemical Groups Most Important to Life distinctive properties of organic molecule depend arrangement of carbon skeleton and chemical groups attached to the skeleton in some cases chemical groups contribute to function primarily by affecting the molecules shape True for sex hormones estradiol and testosterone Functional Groups chemical groups that affect molecular function by being directly involved in chemical reactions each participates in chemical reactions in a characteristic way 7 chem groups most important in biological processes Hydroxyl Carbonyl Carboxyl Amino Sulfhydryl Phosphate and Methyl groups The first six groups excluding the methyl groups also act as functional groups and are except for Sulfhydryl hydrophilic thus increase the solubility of organic compounds in water 4 ATP An Important Source of Energy for Cellular Processes ATP Adenosine Triphosphate consists of an organic molecule called adenosine attached to a string of 3 phosphate groups thought of as storing energy but more accurately storing potential to react with water When 3 phosphates are present ex ATP one phosphate may be split off as a result of a reaction with water losing a phosphate ATP ADP Adenosine Diphosphate Concept 3 2 Macromolecules are Polymers built from the Monomers Polymer long molecule consisting of many similar or identical building blocks linked by covalent 1 bonds its building blocks are monomers 2 Macromolecules in classes organic compounds carbohydrates proteins and nucleic acids are polymers The Synthesis and Breakdown of Polymers Chemical mechanisms by which cells make break down polymers are basically the same in all cases Enzymes specialized macromolecules usually proteins that speed up chemical reactions Dehydration reaction reaction in which 2 molecules are covalently bonded to each other with the loss of a water molecule how monomers are connected to form polymers when bonds form between two monomers each monomer contributes part of the water molecule that is released during the reaction One monomer provide a hydroxyl group OH the other provides a hydrogen H process repeated adding one monomer after the other to form a polymer Polymers Monomers through Hydrolysis a process that is the reverse of dehydration reaction Hydrolysis means breakage using water bond between the monomers is broken by the addition of a water molecule with a hydrogen from the water attaching to one monomer and the hydroxyl group 3 The Diversity of Polymers Molecular difference between human siblings reflect small variations in polymers Molecular differences between unrelated individuals are more extensive and those between species are greater constructed from 40 50 common monomers and some that occur rarely proteins built from 20 kinds of amino acids chain of aminos up to 100 Small molecules common to all organisms are ordered into unique macromolecules Function can still be grouped roughly by class 3 3 Carbohydrates serve as a fuel and building material Carbohydrates include both sugars and polymers of sugars simplest carbohydrates are monosaccharides aka simple sugars monomers form which more are complex carbs are constructed Carbs include macromolecules called polysaccharides polymers composed of many sugar building blocks joined together by dehydration reactions 1 2 Sugars Monosaccharides generally have molecular formulas that are some multiple of the unit CH2O Glucose is the most common monosaccharide Carbonyl group can be on the end of the linear sugar molecule ex glucose or attached to an interior carbon ex fructose Hexoses sugars that have 6 carbons i e Glucose Fructose Trioses 3 carbon