ch03macromolecules2010

8/8/2019 Ch03macromolecules2010

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AP Biology 2007-2008

Chemistry of Carbon

Building Blocks of Life


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AP Biology

Why study Carbon?All of life is built on carbon

Cells~72% H

2O

~25% carbon compoundscarbohydrateslipidsproteinsnucleic acids

~3% saltsNa, Cl, K


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AP Biology

Chemistry of LifeOrganic chemistry is the study of carbon compoundsC atoms are versatile building blocks

bonding properties4 stable covalent bonds

HH C

H

H


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AP Biology

Complex molecules assembled like TinkerToys


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AP Biology

HydrocarbonsCombinations of C & H

non-polar not soluble in H 2Ohydrophobic

stablevery little attractionbetween molecules

methane(simplest HC)


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AP Biology

Hydrocarbon Shapes


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AP Biology

IsomersMolecules with same molecular formulabut different structures (shapes)

different chemical properties

different biological functions

6 carbons

6 carbons

6 carbons


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AP Biology

Form affects functionStructural differences create importantfunctional significance

amino acid alanine

L-alanine used in proteinsbut not D-alanine

Medicines L-DopaL-version activebut not D-version

sometimes withtragic results

stereoisomersstereoisomers


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AP Biology

Form affects functionThalidomide

prescribed to pregnant women in 50s & 60sreduced morning sickness, but

stereoisomer caused severe birth defects


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AP Biology

Trans fats are a type of isomer Fatty acid tails are hydrocarbons.Unsaturated fats have double bondsbetween carbons.

Form follows function!

Trans fats are straight and solidify atroom temperature.

Cis (olive oil)

Trans (partially hydrogenatedvegetable oil)


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AP Biology

Diversity of moleculesSubstitute other atoms or groupsaround the carbon

ethane vs. ethanolH replaced by an hydroxyl group (OH)nonpolar vs. polar

gas vs. liquid

biological effects!

ethane (C 2H6) ethanol (C 2H5OH)


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AP Biology

Functional groupsParts of organic molecules that areinvolved in chemical reactions

give organic molecules distinctive

propertieshydroxyl aminocarbonyl sulfhydrylcarboxyl phosphate

Affect reactivitymakes hydrocarbons hydrophilicincrease solubility in water


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AP Biology

Viva la difference!Basic structure of male & femalehormones is identical

identical carbon skeleton

attachment of different functional groupsinteract with different targets in the bodydifferent effects


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AP Biology

Hydroxyl OH

organic compounds with OH = alcoholsnames typically end in ol

ethanolIncreases polarity of a molecule


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AP Biology

CarbonylC=O

O double bonded to Cif C=O at end molecule = aldehyde

if C=O in middle of molecule = ketone


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AP Biology

Carboxyl COOH

C double bonded to O & single bondedto OH group

compounds with COOH = acidsfatty acidsamino acids


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AP Biology

Amino-NH 2

N attached to 2 Hcompounds with NH 2 = amines

amino acidsNH2 acts as base

ammonia picks up H + from solution


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AP Biology

Sulfhydryl SH

S bonded to Hcompounds with SH = thiols

SH groups stabilize the structure of proteins


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AP Biology

Phosphate PO 4

P bound to 4 Oconnects to C through an O

lots of O = lots of negative chargehighly reactive

transfers energy between organic molecules

ATP, GTP, etc.


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Macromolecules

Building Blocksof Life


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AP Biology

MacromoleculesSmaller organic molecules join together to form larger molecules

macromolecules

4 major classes of macromolecules:

carbohydrates

lipidsproteinsnucleic acids


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AP Biology

H2O

HO

HO H

H HHO

PolymersLong molecules built by linking repeatingbuilding blocks in a chain

monomers

building blocksrepeated small units

covalent bonds

Dehydration synthesisDehydration synthesis


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AP Biology

H2O

HO

HO H

H HHO

How to build a polymer Synthesis

joins monomers by taking H 2O outone monomer donates OH

other monomer donates H +together these form H 2O

requires energy & enzymes

enzymeDehydration synthesisDehydration synthesis

Condensation reactionCondensation reaction

You gottabe open tobonding!


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AP Biology

H2O

HO H

HO H HO H

How to break down a polymer

Digestionuse H2O to breakdown polymers

reverse of dehydration synthesis

cleave off one monomer at a time

H2O is split into H + and OH

H+ & OH attach to ends

requires enzymesreleases energy

Br eaking upis ha r d to do!

HydrolysisHydrolysis

DigestionDigestion

enzyme


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