Building Blocks of Life Chemistry of Carbon Building Blocks of Life

Why do we study carbon? ~72% H2O ~25% carbon compounds ~3% salts All of life is built on carbon Cells… ~72% H2O ~25% carbon compounds carbohydrates lipids proteins nucleic acids ~3% salts Na, Cl, K… What is the main source of carbon? CO2

1. Bond formation and Shapes Carbon can form 4 covalent bonds -Single, double and triple Most Carbon based molecules form: Tetrahedral and flat shapes

Molecular Formula Structural Formula Ball-and-Stick Model Figure 3.2 Molecular Formula Structural Formula Ball-and-Stick Model Space-Filling Model Name Methane Ethane Figure 3.2 The shapes of three simple organic molecules Ethene (ethylene) 4

2. Hydrocarbon Skeletons Combinations of C & H non-polar not soluble in H2O hydrophobic stable very little attraction between molecules methane (simplest HC)

(c) Double bond position Figure 3.4 (a) Length (c) Double bond position Ethane Propane 1-Butene 2-Butene (b) Branching (d) Presence of rings Figure 3.4 Four ways that carbon skeletons can vary Butane 2-Methylpropane (isobutane) Cyclohexane Benzene 6

Numbered carbons C 6' C O 5' C C 4' 1' C C 3' 2'

Form affects function *Structural differences create important functional significance Thalidomide prescribed to pregnant women in 50s & 60s reduced morning sickness, but… stereoisomer caused severe birth defects

3. Chemical Groups Number and arrangement of groups give a molecule unique properties and affect chemical reactivity

Small Changes=Big difference! Basic structure of male & female hormones is identical identical carbon skeleton attachment of different functional groups interact with different targets in the body different effects For example the male and female hormones, testosterone and estradiol, differ from each other only by the attachment of different functional groups to an identical carbon skeleton.

4. Macromolecules Smaller carbon based molecules join together to form larger molecules macromolecules 4 major classes of macromolecules: carbohydrates lipids proteins nucleic acids

Monomers A single unit

A chain of covalently bonded monomers polymers A chain of covalently bonded monomers

Reactants PRODUCTS Ch4 + 2o2 Co2 + 2h20 Chemical Reactions Reactants PRODUCTS Ch4 + 2o2 Co2 + 2h20

Dehydration Synthesis Chemical reaction that covalently bonds two monomers together *Water is lost in the process H2O

Hydrolysis Chemical reaction that breaks the bonds between two monomers by adding water H2O