Biochemistry – Carbohydrates
and Proteins
Contemporary Biology
Monkemeier
Four Classes of Macromolecules
Carbohydrates (Sugars)
 Proteins
 Lipids (Fats)
 Nucleic Acids


All are put together using dehydration
synthesis and broken down using
hydrolysis.
Carbohydrates (sugars)
Carbohydrates contain Carbon (C),
Hydrogen (H), and Oxygen (O) in a
special ratio of 1:2:1.
 The smallest carbohydrates are known
as Monosaccharides.
 Monosaccharides are the subunits
(monomers) that get linked together to
build larger carbohydrates (polymers)

Carbohydrates – The
Monosaccharides
The smallest carbohydrates are called
monosaccharides.
 Monosaccharides contain chemical
energy that organisms use as a source
of quick energy.
 Examples of Monosaccharides are
Glucose, Galactose and Fructose.

Monosaccharides
Disaccharides
Disaccharides are carbohydrates
composed of TWO monosaccharides.
 Disaccharides include: Sucrose, Lactose
and Maltose.
 Sucrose is table sugar and lactose is
found in milk and dairy products.
 People who are lactose intolerant have
trouble breaking the bond between the
two monosaccharides.

Building Disaccharides!

Dehydration Synthesis (aka
Condensation) is used to link two
monosaccharides together.
Polysaccharides
Polysaccharides are composed of many
monosaccharides linked together.
 Examples of polysaccharides include
starch, glycogen, cellulose and chitin.
 Each polysaccharide has its own
function (job).
 Polysaccharides are built using
dehydration synthesis (aka
condensation)

Four Important Polysaccharides
Starch = Plants store glucose as starch
 Glycogen = Fungi and animals store
glucose as glycogen
 Cellulose = Composes plant cell walls
 Chitin = composes the exoskeleton of
arthropods (insects, lobsters, crabs, etc.)

Polysaccharides
Starch vs. Cellulose
Proteins
Proteins have many roles in organisms.
 Proteins

are molecules for structure and support
 can be enzymes which are biological
catalysts
 can act as transport molecules
 are part of structures that help organisms
move

Proteins
Are made of carbon (C), hydrogen (H),
oxygen (O), and nitrogen (N).
 The subunits (monomers) of proteins are
amino acids.
 Amino acids are linked together by
covalent bonds known as peptide bonds
when proteins are made.

Proteins
Proteins are built by using the chemical
reaction known as dehydration
synthesis.
 Amino acids are linked together to build
proteins.
 Amino acids are the monomers
(subunits) of proteins.

Amino Acids = Monomers of
Proteins!
There are 20 different amino acids that
can be used to build a protein.
 Each amino acid has the same basic
structure:

Building Proteins= Forming Peptide
bonds between amino acids!
Enzymes = Special Proteins
Enzymes are proteins that act as
biological catalysts.
 Catalysts speed up chemical reactions
by lowering the amount of energy it takes
for the reaction to start (aka activation
energy)
 Each Enzyme has a specific substance
(substrate) that it acts upon.

Enzymes and Substrates
Each enzyme recognizes its substrate by
its shape.
 The enzyme and substrate fit together
like a “lock and key”.
 If the shape of the enzyme is changed it
will not fit or recognize its substrate and
it will not be able to catalyze the
chemical reaction.

Enzymes and Substrates!
Enzymes and Activation Energy!
Enzymes and Chemical Reactions
Remember that Enzymes speed up
chemical reactions by lowering the
activation energy.
 Each enzyme is specific for its substrate
due to its shape.
 If the shape of the enzyme is affected,
the enzyme will not speed up the
chemical reaction.

Endothermic or Exothermic?
Endergonic or Exergonic?
Endothermic or Exothermic?
Endergonic or Exergonic?
Quiz tomorrow relating to
Carbohydrates and Proteins.