Building Blocks of Life

2007-2008

Organic Chemistry

Why study Carbon?All of life is built on carbon Cells

~72% H2O ~25% carbon compounds

carbohydrateslipidsproteins nucleic acids

~3% salts Na, Cl, K…

Chemistry of LifeOrganic chemistry is the study of carbon

compoundsC atoms are versatile building blocks

bonding properties4 stable covalent bonds

Bonds with CHNOPS – the elements that make up livingthings

HHC

H

H

Complex molecules assembled like TinkerToys

HydrocarbonsCombinations of C & H

non-polar Sharing electrons equallynot soluble in H2Ohydrophobic

stablevery little attraction between moleculesa gas at room temperature

methane(simplest HC)

Hydrocarbons can grow

IsomersMolecules with same molecular formula but

different structures (shapes) different chemical propertiesdifferent biological functions

6 carbons

6 carbons

6 carbons

Diversity of moleculesSubstitute other atoms or groups around

the carbonethane vs. ethanol

H replaced by an hydroxyl group (–OH)

nonpolar vs. polarShare e- equally vs. do not share e- equally

gas vs. liquidbiological effects!

ethane (C2H6) ethanol (C2H5OH)

Functional groupsParts of organic molecules that are involved

in chemical reactionsgive organic molecules distinctive properties

hydroxyl amino carbonyl sulfhydryl carboxyl phosphate

Affect reactivitymakes hydrocarbons polar and hydrophilic increase solubility in water

Viva la difference!Basic structure of male & female

hormones is identicalidentical carbon skeleton attachment of different functional groupsinteract with different targets in the body

different effects

Hydroxyl–OH

organic compounds with OH = alcohols names typically end in -ol

ethanol

CarbonylC=O

O double bonded to Cif C=O at end molecule = aldehydeif C=O in middle of molecule = ketone

Carboxyl –COOH

C double bonded to O & single bonded to OH groupcompounds with COOH = acids

fatty acidsamino acids

Amino-NH2

N attached to 2 Hcompounds with NH2 = amines

amino acids

NH2 acts as base

ammonia picks up H+ from solution

Sulfhydryl –SH

S bonded to Hcompounds with SH = thiolsSH groups stabilize the structure of

proteins

Phosphate –PO4

P bound to 4 O connects to C through an Olots of O = lots of negative charge

highly reactive

transfers energy between organic molecules ATP, ADP, etc.

MacromoleculesSmaller organic molecules join together to

form larger moleculesmacromolecules

4 major classes of macromolecules:carbohydrateslipidsproteinsnucleic acids

H2O

HO

HO H

H HHO

PolymersLong molecules built by linking repeating

building blocks in a chain monomers

building blocksrepeated small units

covalent bonds

Dehydration synthesisDehydration synthesis

H2O

HO

HO H

H HHO

How to build a polymerSynthesis

joins monomers by “taking” H2O outone monomer donates OH–

other monomer donates H+ together these form H2O

requires energy & enzymes

enzymeDehydration synthesisDehydration synthesis

Condensation reactionCondensation reaction

H2O

HO H

HO H HO H

How to break down a polymerHydrolysis (digestion)

use H2O to breakdown polymers reverse of dehydration synthesiscleave off one monomer at a timeH2O is split into H+ and OH–

H+ & OH– attach to endsrequires enzymesreleases energy

HydrolysisHydrolysis

DigestionDigestion

enzyme