CARBOHYDRATES (MONOMERS)
Monosaccharides are the monomers from which larger
carbohydrates are made. Glucose, galactose and fructose are
common monosaccharides.
A condensation reaction between two monosaccharides forms a
glycosidic bond.
Disaccharides are formed by the condensation of two
monosaccharides:
•• maltose is a disaccharide formed by condensation of two glucose
molecules
•• sucrose is a disaccharide formed by condensation of a glucose
molecule and a fructose molecule
•• lactose is a disaccharide formed by condensation of a glucose
molecule and a galactose molecule.
Mono-saccharrides and Di-saccharides
Quick recall test:
1-10 in back of notes

Carbohydrates are a large
group of molecules. They are
named Saccharides.
Task: Sort these Saccharides
into whether you think they are
monomers, dimers, or polymers
Outcomes:
- Define the terms
monosaccharides and
disaccharides
- Give examples of monoand disaccharides with
chemical formula
- Describe the reactions
that form different
disaccharides using word
equations.
- Use structural formula
to show the reactions
between monomers to
form dimers.
Starch
Sucrose
Glucose
Cellulose
Maltose
Galactose
Glycogen
Lactose
Fructose
Starch
Sucrose
Glucose
Cellulose
Maltose
Galactose
Glycogen
Lactose
Fructose
Forming disaccharides
You cant make a polymer like starch by magic.
You start with the monomers.

Glucose + Glucose → Maltose + Water

Glucose + Fructose → Sucrose + Water

Glucose + Galactose → Lactose + Water
Q: Which are the monomers in these reactions?
Q: Which are the dimers?
Q: What kind of reaction is shown here? How
can you tell?
Outcomes:
- Define the terms
monosaccharides
and disaccharides
- Give examples of
mono- and
disaccharides with
chemical formula
- Describe the
reactions that
form different
disaccharides using
word equations.
- Use structural
formula to show
the reactions
between monomers
to form dimers.
Structural Formula of α- glucose (monomer)

Chemical formula of glucose is:
_________
Outcomes:
- Define the terms
monosaccharides and
disaccharides
- Give examples of monoand disaccharides with
chemical formula
- Describe the reactions
that form different
disaccharides using word
equations.
- Use structural formula
to show the reactions
between monomers to
form dimers.
Forming Maltose - Condensation
+H2O
When Maltose is made, the 2 glucose molecules react.
This happens at the 1C and the 4C.
A H and an OH are removed and the glucose molecules join.
The bond they form is called the glycosidic bond.
The H and OH removed make H2O.
Whiteboards - Plenary

1.
2.
3.
4.
5.
6.
7.
8.
Answer these questions 1 at a time on the whiteboards:
What does the term Saccharide mean?
Example of a monosaccharide, disaccharide,
polysaccharide
What type of reaction joins 2 monosaccharides
together to make a disaccharide?
Chemical formula of glucose
Word equations for formation of Maltose and fructose
and lactose
What is a glycosidic bond?
Structural formula of α- glucose (numbered)
Add on to the diagram to show how maltose is formed.

1.
2.
3.
4.
5.
You have in your notes the structural
formula of α-glucose and the
structural formula showing the
forming reaction to make maltose.
Draw the structural formula of
fructose
Draw the structural formula of
galactose
Draw the structural formula of the
reaction between glucose and
fructose to make sucrose (Show the
condensation reaction happening and
the glycosidic bond)
Draw the structural formula of the
reaction between glucose and
galactose to make sucrose (Show the
condensation reaction happening and
the glycosidic bond)
Draw the hydrolysis reaction of
maltose back into 2 glucose units.
Homework
Due Friday
Outcomes:
- Define the terms
monosaccharides and
disaccharides
- Give examples of monoand disaccharides with
chemical formula
- Describe the reactions
that form different
disaccharides using word
equations.
- Use structural formula
to show the reactions
between monomers to
form dimers.