Functional Groups
Functional Groups
 Functional groups are
groups of organic
molecules that react in
predictable ways
 We use them to
understand biochemical
reactions between
carbohydrates, fatty
acids, proteins and
nucleic acids
Condensation reactions dehydration synthesis
 Take a look at the
reaction drawn here
 Name the functional
groups involved
 This is a reaction that
bonds two glucose
molecules together
and produces maltose
and water
Dehydration synthesis between
two hydroxyl groups
 Hydroxyl groups
characterize alcohols and
sugars
 They are polar and
participate in the the
synthesis reactions that
build starches from
simple sugars
 This diagram continues
where the previous one
left off - the synthesis of
maltose from two
glucose molecules
Dehydration synthesis of
sucrose
 In this example, one
glucose is replaced
with fructose
 The reaction is the
same though,
because the
functional groups are
both hydroxyl - like
the 2 glucose
molecules
Carbonyl groups
 Carbonyl groups are also
polar
 They can be found at the
end of the carbon chain,
or in the middle
 They are characteristic
groups in ketones and
aldehydes
 Simple sugars contain
polar carbonyl groups they are either ketose
sugars (fructose) or
aldose sugars (glucose)
Carboxyl Groups
 These polar groups are
characteristic of organic
acids
 They are particularly
important to fatty acids the long carbon chains
are unreactive and nonpolar, but dehydration
synthesis reactions can
occur at the functional
group end
Amino Groups
 Amino groups are
basic and polar and
characterize amino
acids, the building
blocks of protein
 What is the second
functional group that
characterizes amino
acids?
Amino acids and peptide
bonds
 These two groups are
critically important
in the formation of
proteins
 Peptide bonds form
between the two
functional groups another example of
dehydration synthesis
Phosphate groups and
sulfhydryl groups
 Phosphate groups are
responsible for
bonding with
hydroxyl groups in
the backbone of
DNA molecules
 Sulfhydryl groups
react with each other,
forming covalent
bonds in proteins