Chemistry
Functional Groups
Organic Chemistry
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The study of carbon-containing compounds
Carbon atoms are the most versatile building blocks of
molecules
With a total of 6 electrons, a carbon atom has 2 in the
first shell and 4 in the second shell
Carbon usually completes its valence shell by sharing
electrons with other atoms in four covalent bonds
This tetravalence by carbon makes large, complex
molecules possible
Carbon Chains
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form the skeletons of most organic molecules
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the skeletons may vary in length and may be straight,
branched, or arranged in closed rings
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the carbon skeletons may also include double bonds
Isomers
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Structural isomers
Geometric isomers
Enantiomers
Structural Isomers
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Variation in covalent partners
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Pentane has a straight skeleton and isopentane
has a branched skeleton
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Same molecular formula C5H12
Geometric Isomers
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Variation in arrangement about a double bond
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Example: rhodopsin (in the retina) from one
geometric isomer to another
Enantiomers
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Variation in spatial arrangement, mirror images
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enantiomers are possible if there are four different
atoms or groups of atoms bonded to a carbon
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they are like left-handed and right-handed versions
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usually one is
biologically active,
the other inactive
Functional Group
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A specific configuration of atoms commonly
attached to the carbon skeletons of organic
molecules and usually involved in chemical
reactions
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Hydroxyl
-OH
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Carbonyl
CO
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Carboxyl
-COOH
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Amino
-NH2
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Sulfhydryl
-SH
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Phosphate
-PO4-2 (-OPO3-2)
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Methyl
-CH3
1.Hydroxyl Group (-OH)
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a hydrogen atom forms a polar
covalent bond with an oxygen which
forms a polar covalent bond to the
carbon skeleton
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Organic compounds with hydroxyl
groups are alcohols and their names
typically end in –ol
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example ethanol
2.Carbonyl Group ( CO)
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consists of an oxygen atom joined
to the carbon skeleton by a
double bond
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ketone - if not at the end
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example: acetone
aldehyde -if the carbonyl group
is on the end of the skeleton
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example: propanal
3.Carboxyl Group (-COOH)
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carbon atom with a double bond with
an oxygen atom and a single bond to
a hydroxyl group.
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carboxylic acids – compounds with
carboxyl groups
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Acidic properties - because the
combined electro negativities of
the two adjacent oxygen atoms
increase the dissociation of
hydrogen as an ion (H+)
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Example: acetic acid (vinegar)
4. Amino Group (-NH2)
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Nitrogen atom attached to two
hydrogen atoms and the carbon skeleton.
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Amines - Organic compounds with amino groups.
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Basic properties - because ammonia can pick up a
hydrogen ion (H+) from the solution
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Example: amino acids
5. Sulfhydryl Group (-SH)
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sulfur atom bonded to a
hydrogen atom and to the
backbone
thiols - organic molecules
with sulfhydryl
Sulfhydryl groups help stabilize
the structure of proteins
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Example: amino acid Cysteine
6. Phosphate Group
(-OPO3-2)
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Phosphorus bound to four oxygen atoms (three with
single bonds and one with a double bond).
Phosphate groups are anions with two negative charges
as two protons have dissociated from the oxygen
atoms.
One function of phosphate groups is to transfer energy
between organic molecules.
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Example ATP
7. Methyl Group (-CH3)
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Carbon bonded to 3 hydrogen
atoms. The methyl group may be
attached to a or a different atom.
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Addition of methyl to molecule
changes its shape and function
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Example: 5-Methyl cytidine
Activity
Identify the functional groups
H
C-N
H
H
Methylamine
H
H
H
H
O
Alanine
N-C-C
OH
H
CH3
Activity
Identify the functional groups
ATP (adenosine triphosphate)
The End