Carbon and the Molecular Diversity of Life Chapter 4 Carbon and the Molecular Diversity of Life

Overview: Carbon: The Backbone of Life Although cells are 70–95% water, the rest consists mostly of carbon-based compounds Carbon has is unparalleled in its ability to form large, complex, and diverse molecules Carbon compounds are found in: Proteins DNA Carbohydrates, Other molecules that distinguish living matter Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Concept 4.1: Organic chemistry is the study of carbon compounds Organic Chemistry is the study of compounds that contain carbon Organic compounds range from simple molecules to colossal (huge) ones Most organic compounds contain: Hydrogen atoms Carbon atoms Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Why can Carbon form large complex and divers molecules? It has 4 Valence Electrons It can form 4 Covalent Bonds Bonds can be Single Double Triple Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Why can Carbon form large complex and divers molecules? It can form large molecules Molecules can be: Chains Ring-Shaped Branched Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Formation of Bonds with Carbon - Shapes Carbon has 4 Valence Electrons (tetravalent) When carbon forms: 4 single bonds  Tetrahedral Shape A double bond  Flat Shape Name Molecular Formula Structural Formula Ball-and-Stick Model Space-Filling (a) Methane (b) Ethane (c) Ethene (ethylene) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Most common carbon covalent bonds in living organisms: Hydrogen Oxygen Nitrogen “Building code” that governs the architecture of living molecules Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Example: Carbon dioxide: CO2 O = C = O Urea: CO(NH2)2 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Molecular Diversity Arising from Carbon Skeleton Variation Carbon chains form the skeletons of most organic molecules Carbon chains vary in length and shape Ethane Propane 1-Butene 2-Butene (c) Double bonds (d) Rings Cyclohexane Benzene Butane 2-Methylpropane (commonly called isobutane) (b) Branching (a) Length Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Many organic molecules, such as fats, have hydrocarbon components Hydrocarbons Hydrocarbons are organic molecules consisting of only carbon and hydrogen Many organic molecules, such as fats, have hydrocarbon components Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Structure predicts function: Draw Diagram of hydrocarbon tail in cell membrane & explain how it makes cell membrane selective

Hydrocarbons Hydrocarbons can undergo reactions that release a large amount of energy Eg. Diesel Fuel - Nonane Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Isomers Isomers are compounds with the same molecular formula but different structures and properties Structural isomers have different covalent arrangements of their atoms Example: C5H12 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Isomers Geometric isomers have the same covalent arrangements but differ in spatial arrangements Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Isomers Enantiomers are isomers that are mirror images of each other Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Enantiomers are important in the pharmaceutical industry: Two enantiomers of a drug may have different effects Example: Thalidomide for pregnant women Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Effective Enantiomer Ineffective Enantiomer Drug Condition Pain; inflammation Ibuprofen S-Ibuprofen R-Ibuprofen Figure 4.8 The pharmacological importance of enantiomers Albuterol Asthma R-Albuterol S-Albuterol

Differing effects of enantiomers demonstrate that organisms are sensitive to even subtle variations in molecules Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Distinctive properties of organic molecules depend on: Concept 4.3: A small number of chemical groups are key to the functioning of biological molecules Distinctive properties of organic molecules depend on: The Carbon skeleton Molecular components attached to it (aka functional groups) A number of characteristic groups are often attached to skeletons of organic molecules Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Chemical Groups Most Important in the Processes of Life Functional groups are the components of organic molecules that are most commonly involved in chemical reactions The number and arrangement of functional groups give each molecule its unique properties Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Estradiol Testosterone Fig. 4-9 Figure 4.9 A comparison of chemical groups of female (estradiol) and male (testosterone) sex hormones

The seven functional groups that are most important in the chemistry of life: Hydroxyl group Carbonyl group Carboxyl group Amino group Sulfhydryl group Phosphate group Methyl group Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Group Structure Hydroxyl -OH Alcohols & helps dissolve molecules such as sugar Carbonyl -CO Ketones & Aldehydes such as sugars Carboxyl -COOH Fatty Acids & Sugars Amino -NH2 Amino Acids Sulfhydryl -SH Proteins Phosphate PO3 ATP, DNA, Phospholipids Methyl CH3 DNA

ATP: An Important Source of Energy for Cellular Processes Adenosine triphosphate (ATP): Is the primary energy-transferring molecule in the cell Organic molecule called adenosine Three phosphate groups Adenosine Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Reacts with H2O Energy ATP Inorganic phosphate ADP Adenosine Adenosine Fig. 4-UN4 Reacts with H2O P P P Adenosine P i P P Adenosine Energy ATP Inorganic phosphate ADP

You should now be able to: Explain how carbon’s electron configuration explains its ability to form large, complex, diverse organic molecules Describe how carbon skeletons may vary and explain how this variation contributes to the diversity and complexity of organic molecules Distinguish among the three types of isomers: structural, geometric, and enantiomer Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Name the major functional groups found in organic molecules; describe the basic structure of each functional group and outline the chemical properties of the organic molecules in which they occur Explain how ATP functions as the primary energy transfer molecule in living cells Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings