Transcript Carbon and the Molecular Diversity of Life

The Carbon Atom
Isomers
Functional Groups
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Organic compounds are carbon compounds.
Organic chemistry is carbon chemistry.
Carbon has little tendency to gain or lose electrons.
It has a valence number of 4 and forms four covalent bonds.
Each carbon atom in a carbon compound is an intersection
point and so a molecule can branch off in four directions. This
makes it TETRAVALENT.
Single covalent bonds form a tetrahedron like methane.
Four single bonds form 2 tetrahedrons joined at the apex like
ethane.
When 2 carbon atoms are joined by a double bond, all bonds
around those carbons are in the same plane, like ethane.
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Isomers vary in structure while having the same molecular
formula. Because they have different structures they often
have different properties.
1.STRUCTURAL ISOMERS differ in covalent partners.
Ex: Butane and Isobutane Page 56
2. GEOMETRIC ISOMERS differ in arrangement about a
double bond.
Illustration Page 56
3. ENANTIOMERS differ in spatial arrangement around
an asymmetric carbon resulting in molecules that are mirror
images.
Illustration Page 56 Ex: Thalidomide
 Functional
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Groups
Certain groups of atoms called
functional groups attached to carbon
skeletons impart specific properties to
carbon compounds.
 We will be examining about 7 of these
groups.
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( See handout or page 58 in your text)
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 Alcohols-hydroxyl
group-end in –ol
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Hydroxyl group is polar-water
dissolves organic compounds with
multiple hydroxyl groups like sugars.
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 Carbonyl
Group – COH with a double
bond between the carbon and oxygen.
• if it occurs at the end of a carbon skeleton it is
called an aldehyde (ex: Propanal)
• if it occurs anywhere else it is a ketone (ex:
acetone)
 Carboxyl
Group- COOH- carbon attached
to an oxygen with a
 Double bond and an OH with a single
bond. If it loses a hydrogen ion it
becomes COO (onized form) For this
reason these compounds are often called
carboxylic acids. (EX: acetic acid or
vinegar)
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 Amino
Group-NH2 (ionized) or NH3Amines or amino acids
 Like glycine.
 Sulfhydryl
Group- SH- Thiols
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 Phosphate
Group-PO3-organic
phosphates-DNA ATP
 Phospholipids
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 7. Methyl
Group- CH3- fatty acids, oils
and waxes