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Chapter 4. Carbon and the Molecular Diversity of Life. Figure 4.1. Carbon Chemistry. Carbon is the backbone of biological m olecules (macromolecules) All living organisms are made up of chemicals based mostly on the element carbon. Carbon Chemistry.
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Chapter 4 Carbon and the Molecular Diversity of Life
Figure 4.1 Carbon Chemistry • Carbon is the backbone of biological molecules (macromolecules) • All living organisms are made up of chemicals based mostly on the element carbon
Carbon Chemistry • Organic chemistry is the study of carbon compounds • Carbon atoms can form diverse molecules by bonding to four other atoms • Carbon compounds range from simple molecules to complex ones • Carbon has four valence electrons and may form single, double, or triple.
Ball-and-Stick Model Name and Comments Space-Filling Model Molecular Formula Structural Formula H (a) Methane CH4 C H H H H H (b) Ethane C2H6 C H C H H H H H (c) Ethene (ethylene) C C C2H4 H H Figure 4.3 A-C • The bonding versatility of carbon allows it to form many diverse molecules, including carbon skeletons
Carbon (bonds = 4) Nitrogen (bonds = 3) Hydrogen (bonds = 1) Oxygen (bonds = 2) O H N C Figure 4.4 • The electron configuration of carbon gives it covalent compatibility with many different elements
H H C C C C H H C H H H H H H C H H H H H H H H H H H H C C C C C C C H H H H H H H H H H H H (a) Length H Ethane Propane H H H H H H H H H H H C C C C C C C C H H H H (b) Branching n-Butane isobutane H H H H C H (c) Double bonds H H C C C H H C C H H C C 1-Butene 2-Butene H H C C C (d) Rings Figure 4.5 A-D Cyclohexane Benzene • Carbon may bond to itself forming carbon chains • Carbon chains form the skeletons of most organic molecules • Carbon chains vary in length and shape
Fat droplets (stained red) 100 µm (b) Mammalian adipose cells (a) A fat molecule Figure 4.6 A, B Hydrocarbons • Hydrocarbons are molecules consisting of only carbon and hydrogen • Hydrocarbons Are found in many of a cell’s organic molecules
H H H C H H C H H H H H H H (a) Structural isomers H C C C C C H H C H C C H H H H H H H H H X X X C C C C (b) Geometric isomers X H H H CO2H CO2H C C (c) Enantiomers H H NH2 NH2 CH3 CH3 Figure 4.7 A-C Isomers • Isomers are molecules with the same molecular formula but different structures and properties • Three types of isomers are • Structural • Geometric • Enantiomers
L-Dopa (effective against Parkinson’s disease) D-Dopa (biologically inactive) Figure 4.8 • Enantiomers Are important in the pharmaceutical industry
OH CH3 Estradiol HO Female lion OH CH3 CH3 O Testosterone Male lion Figure 4.9 Functional Groups • Functional groups are the parts of molecules involved in chemical reactions • They are the chemically reactive groups of atoms within an organic molecule • They giveorganic molecules distinctive chemical properties
Seven functional groups are important in the chemistry of life • Hydroxyl • Carboxyl • Amino • Phosphate • Carbonyl • Methyl • Sulfhydryl
FUNCTIONAL GROUP HYDROXYL CARBONYL CARBOXYL O O OH C C OH (may be written HO ) In a hydroxyl group (—OH), a hydrogen atom is bonded to an oxygen atom, which in turn is bonded to the carbon skeleton of the organic molecule. (Do not confuse this functional group with the hydroxide ion, OH–.) STRUCTURE The carbonyl group( CO) consists of a carbon atom joined to an oxygen atom by a double bond. When an oxygen atom is double-bonded to a carbon atom that is also bonded to a hydroxyl group, the entire assembly of atoms is called a carboxyl group (—COOH). Figure 4.10 Some important functional groups of organic compounds
Ketones if the carbonyl group is within a carbon skeleton Aldehydes if the carbonyl group is at the end of the carbon skeleton NAME OF COMPOUNDS Alcohols (their specific names usually end in -ol) Carboxylic acids, or organic acids EXAMPLE H H H H O O C C H OH C C H C H C H OH H H H H C Ethanol, the alcohol present in alcoholic beverages H H Acetic acid, which gives vinegar its sour tatste Acetone, the simplest ketone H H O H C C C H H H Propanal, an aldehyde Figure 4.10 Some important functional groups of organic compounds