1. What’s the question?
1.Polymer
2.Monosaccharide
3.Red
Here's the answers,
all you have to do is
write the questions!

2. Carbohydrates-
Polysaccharides
Objective: To understand how
monosaccharides form
polysaccharides.
Outcomes:
~ Describe what a disaccharide is and
name examples.
~ Explain how monosaccharides are
linked to form polysaccharides.
~ Explain how to carry out a test for
non-reducing sugars and for starch.
Sunday, 28 September 2014
Keywords
Disaccharide
Polysaccharide
Condensation
reaction
Glycosidic bond
Hydrolysis

3. Disaccharides
Monosaccharide +
monosaccharide =
disaccharide
Monosaccharide Monosaccharide Disaccharide
Glucose Glucose Maltose
Glucose Fructose Sucrose
Glucose Galactose Lactose

4. How?
glucose + glucose maltose + water
Glycosidic bond
Condensation reaction

5. Test for non-reducing sugars (Sucrose)
1.Confirm that the sample you’re testing
is not a reducing sugar.
2.Add 2cm3 of food sample (liquid form)
to 2cm3 of dilute hydrochloric acid and
place in a gently boiling water bath for
5mins.
3.Slowly add sodium hydrogen
carbonate solution. Check the solution
is then neutral.
4.Re-test this solution now again with
Benedict’s.

6. Test for non-reducing sugars (Sucrose)
Hydrochloric acid is added to the sample because…
Sodium hydrogencarbonate is added because…
If a non-reducing sugar is present, the Benedict’s
reagent will now turn red because…

7. Polysaccharides
Polymers.
Large molecules yet
compact.
Insoluble.
e.g. Starch
Hydrolysed
into glucose.
Starch granules in
plant cells

8. e.g. Cellulose
Provides structural
support in plant
cells.

9. Test for starch
1.Add two drops of
sample onto a
spotting tile.
2.Add two drops of
potassium iodide.
3.Starch indicated by
blue-black result.

10. 2.3 Carbohydrates-disaccharides and
polysaccharides
Forming and breaking glycosidic bonds
Complete the diagrams below to show how
glycosidic bonds can be formed and broken.
This type of reaction is called a…
The molecule formed is…
This type of reaction is called a…
The molecules formed are…