ORGANIC CHEMISTRY

Campbell and Reece Chapter 4

Organic Chemistry

study of carbon compounds (most also have hydrogen)

range from small molecules (methane has 4 atoms) to very large one (proteins can have thousands of atoms)

Major Elements of Life

Carbon Hydrogen Oxygen Nitrogen Sulfur Phosphorus

Carbon is very Versatile

because C can form 4 covalent bonds these 6 elements can form an almost limitless # organic molecules

VITALISM

Some credit Hippocrates Simply stated: there is a

life force outside physical & chemical laws

Jons Jakob Berzelius

Swedish chemist in early 1800’s

“Organic compounds come from living things” (only )

so inorganic compounds found only in nonliving things

Fredrich WÖhler German chemist 1828: synthesized urea in

lab (normally made in kidney)

Did not convince Vitalists because he 1 reactant he used came from animal blood

Urea

Hermann Kolbe

Student of Wohler Synthesized urea using

only inorganic reactants….. Crushed Vitalism…..sorry

Yoda

Origin of Life on Earth

Stanley Miller, 1953 Designed experiment

trying to re-create conditions on early Earth

Hypothesized : abiotic synthesis of organic compounds possible

Miller’s Experiment

Closed system Flask of water (early seas)

heated Water vapor rose to another

higher chamber containing “atmosphere”

Sparks added (lightening) “rain” formed, cooled material

collected analyzed

Miller’s Experiment

Miller’s Conclusion

Complex organic compounds could form spontaneously under conditions thought to exist on early Earth

Miller’s Results

2008: re-analyzed some samples from Miller’s experiments in the 1950’s

Additional organic compounds identified

Organic Chemistry

Definition changed to: Study of Carbon

Compounds (regardless of origin)

Bonding with Carbon

C has 4 valence e- Bonds possible:

4 single covalent bonds 2 single & 1 double covalent

bond 2 double covalent bonds 1 single & 1 triple covalent

bond

Bonding with Carbon

Carbon Skeletons

Carbon chains form the backbone of most organic molecules

These skeletons can be Straight

Branched

Carbon Skeleton Variation

In rings:

Carbon Skeleton Variation

1 important source of molecular complexity & diversity that characterizes living organisms

Hydrocarbons

C & H Major components of petroleum

products (fossil fuels) When organism dies all water

soluble compounds wash away as it decays.

Fats stay behind hydrocarbons Burn fossil fuels because they

release a large amount of energy

Fossil Fuels

Isomers Cpds with same # and types

of atoms but they are arranged differently

Different structures behave differently

3 types:1. Structural Isomers2. Cis/trans Isomers3. enantiomers

Structural Isomers

Differ in covalent arrangements of their atoms

Molecular formula same, structure different

Structural Isomers

# possibilities for different arrangements of atoms increases dramatically as carbon skeleton increases in size

Cis-trans Isomers

aka geometric isomers Carbons have covalent

bonds with same atoms but these atoms differ in their spatial relationship

Cis-trans Isomers

In cis groups are on same side of Carbon

In trans groups are across from each other

Cis-trans Isomers The difference in cis-trans

can dramatically affect the biological behavior of the molecule

Enantiomers

Isomers that are mirror images of each other

Differ in shape due to having asymmetric carbon

Enantiomers

Usually only 1 is biologically active

Other 1 may have much milder effect

Functional Groups

Portion of molecule that participates in chemical reactions in a characteristic way

7 common, & very important functional groups in organic chemistry

HYDROXYL-OH

Make alcohols Properties:1. Polar2. Can for H-Bonds with

water (help cpd dissolve in water)

CARBONYL-C=O

Makes:1. Ketones: if in middle of

molecule2. Aldehyde: if at end of

molecule Properties:1. can be isomers2. ketoses/aldoses

CARBOXYL-COOH

Makes: organic acids Properties:1. Can donate H+ COO-2. Mostly found in cells in

ionized form (charge of -1) & called a carboxylate ion

3. In amino acids

CARBOXYL

AMINO-NH2

Makes: Amines Properties:1. Acts as a base (can take H+)2. Found in cells in ionized

form with +1 charge3. in amino acids

AMINE

SULFHYDRYL-SH

Makes: thiols Properties:1. 2 –SH can react forming

disulfide bridges These bridges make

hair curly

PHOSPHATE-PO4

Structure: 2 O have (-) charge

Makes: Organic phosphates

Properties: Makes molecule polar (-1)

charge when in middle, (-2) when on end

Can react with water energy

PHOSPHATE

METHYL-CH3

Makes: Methylated compounds

Properties: When attached to DNA, affects

expression of genes Attachment to Testosterone

changes biological effect compared to Estrogen (without methyl group)

METHYL

ADENOSINE TRIPHOSPHATE

ATP Made of adenosine + 3 phosphate groups

When 3 phosphates in series, easy to remove 3rd group with water

Hydrolysis of ATP