Carbohydrates
Biochemistry,
Organic Molecules
I. Introduction
A.Organic
molecules in living things can
be classified into 4 groups:
1. Carbohydrates
2. Lipids
3. Proteins
4. Nucleic Acids
Carbohydrates
1.
2.
3.
Often called sugars and starches.
Functions – energy, structural support
Carbs are made of:
C atoms
 H atoms
 O atoms

NOTE! All carbs contain 2 H atoms for each
O atom. 2 H:1 O
Monosaccharide
 Means
“single sugar”
 They are the monomers (building
blocks) of a carbohydrate molecule.
 They are the major nutrient for
cells.
 Cells use energy stored in these
molecules during cellular
respiration.
Examples of Monosaccharides
1.
2.
3.
Glucose: Sugar produced by
green plants (C6H12O6)
Galactose: Found in milk
Fructose: Sweetest of the 3;
found in fruit.
Examples of Monosaccharides
 The
functional group of a
monosaccharide is (--OH).
 It
is called a Hydroxyl Group.
NOTE! Do not confuse the hydroxyl group (-OH)
with the hydroxide ion (OH-) found in bases!
Functional Groups
 groups
of atoms attached to
carbon skeletons of organic
molecules that are most
commonly involved in
chemical reactions.
Sugars Contain a
Great Deal of Energy.
 Energy is stored in the
chemical bonds.
 Energy is released when the
bonds are broken.
Dehydration Synthesis
 The
chemical reaction that joins
monomers together by removing a
molecule of water.
 Dehydration
= “loss of water”
 Synthesis = “putting together”
Dehydration Synthesis
 Disaccharide
= A molecule
formed by the joining of two
single sugars. Ex. Table sugar
(sucrose)
 Polysaccharide = “Many sugars”
Living things store excess sugar
in this form. Ex. Cellulose – plants,
Glycogen - Animals
Disaccharides
Hydrolysis (Condensation)
 The
exact opposite of
Dehydration Synthesis.
 A molecule of water is added
to break a bond.
Review
Recap!
 starts with two separate
things, ends with one, removes
water
 Hydrolysis  starts with one
thing, ends with two, adds water
 D.S.