CHNOPS: The Six Key Elements of Life Most biological molecules are made from covalent combinations of these six elements

The backbone of the complex molecules needed for life Of these CARBON is key The backbone of the complex molecules needed for life aka organic molecules

C atoms are versatile building blocks • valence = 4 • oxidation = +/-4 therefore form 4 bonds therefore • potential to create large (macro) molecules • great variety of forms yields molecule diversity!

HYDROCARBONS : C & H atoms exclusively Non-polar: not water soluble; hydrophobic Stable: octet rule fufilled via covalent bonding Methane : CH4 Simplest hydrocarbon formula

H-C chains & rings; big and small

Shape Matters form affects function same formula, different shape defines isomers Ex: C6H14 The molecular formula C6H14 may refer to: * Dimethylbutane (disambiguation) o 2,2-Dimethylbutane o 2,3-Dimethylbutane * Hexane * Methylpentane (disambiguation) o 2-Methylpentane o 3-Methylpentane

Ex: Thalidomide • synthesized in1950’s • prescribed for morning sickness (pregnancy) • one isomer caused severe limb defects (form) (function)

Substituting other atoms or groups around the carbon changes the function as well Ex: ethane vs. ethanol H replaced by an hydroxyl group (–OH) nonpolar becomes polar gas becomes liquid

Ex: structure of male & female hormones • identical carbon skeleton • attachment of different functional groups • interact with different targets in the body • creates different effects

Organizing all this diversity • Sort chemicals into families defined by their functional groups which give organic molecules distinctive properties So What? Functional groups affect reactivity making hydrocarbons hydrophilic therefore increasing solubility in water

Functional Groups be able to recognize these! and: COOH NH2 PO4 OH CO Methyl CH3 Proteins

carboxyl methyl amino methyl carboxyl

MACROMOLECULES Bigger still Organic More complex C, H, O, N atoms CELLULOSE polypeptide polysaccharide