Chapter 4.Chapter 4.

The Chemistry of The Chemistry of CarbonCarbon

Why study Carbon?Why study Carbon?All living things are made of cells Cells

◦~72% H2O ◦~3% salts (Na, Cl, K…)◦~25% carbon compounds

◦carbohydrates◦ lipids◦proteins ◦nucleic acids

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Chemistry of LifeChemistry of Life

Organic chemistry is the study of carbon compounds

C atoms are versatile building blocks◦bonding properties◦4 stable covalent bonds -

pair of electrons are shared

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Complex molecules assembled like –candy & toothpicks

HydrocarbonsHydrocarbonsSimplest Carbon molecules =

hydrocarbons ◦A compound with a combination of Carbon &

Hydrogen

Simplest HC molecule = methane◦1 carbon bound to 4 H atoms◦stable◦a gas at room temperature

Hydrocarbons can growHydrocarbons can grow

adding C-C bonds◦straight line

ethane hexane

◦branching isohexane

◦ring cyclohexane

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ethane

hexane

cyclohexaneisohexane

methane

Diversity of organic moleculesDiversity of organic molecules

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IsomersIsomersMolecules with same molecular formula

but different structures ◦different chemical properties – C6H14

Various kinds of isomersVarious kinds of isomersMolecules differ in structural

arrangement of atoms

Around a double bond – alkenes

Isomers of ethene

Three of the four classes of macromolecules form chainlike molecules called polymers.◦Polymers consist of many similar or identical

building blocks linked by covalent bonds.

The repeated units are small molecules called monomers. (like links of a chain)

Most macromolecules are polymersMost macromolecules are polymers

4 MAIN MACROMOLECULES4 MAIN MACROMOLECULES

MOLECULE MONOMER USESProteins (amino acids) support/motionLipids (glycerol & fatty acids) energy storage/insulation

Carbohydrates (monosaccharides) quick energyNucleic acids (nucleotides) store information

• They all contain CARBON and are called ORGANIC molecules (Also hydrogen, oxygen are in all of them)

Diversity of moleculesDiversity of moleculesSubstitute other atoms or groups

around the C◦ethane vs. ethanol

H replaced by an hydroxyl group (–OH)

ethanolethane

What element is the blue one above? How many bonds does it form?

HydroxylHydroxyl

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

ethanol

More on More on Functional GroupsFunctional Groups

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Types of functional groupsTypes of functional groups

6 functional groups most important to chemistry of life:◦hydroxyl amino◦carbonyl sulfhydryl◦carboxyl phosphate

Affect reactivity◦hydrophilic ◦increase solubility in water◦Change all kinds of properties

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Carboxyl Carboxyl

–COOH ◦C double bonded to O & single bonded to OH

group compounds with COOH = acids

◦fatty acids◦amino acids

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AminoAmino

-NH2 ◦N attached to 2 H

compounds with NH2 = amines◦amnio acids

NH2 acts as base ◦ammonia picks up H+ from solution

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Viva la difference!Viva la difference!Basic structure of male & female

hormones is identical◦identical C skeleton ◦attachment of different functional groups◦interact with different targets in the body

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