1. 1. Sufferers of bowel cancer sometimes have to
have part of their small intestines removed to
prevent the cancer from spreading.
Suggest one symptom a person may experience
from this. Give a reason for your answer.
2. Antacids can be taken to treat indigestion.
Antacids work by neutralising excess stomach
acid. Suggest how taking antacids may have an
effect on digestion.

2. Carbohydrates-
Monosaccharides
Objective: To understand how
carbohydrates are made up of simple
units know as monosaccharides.
Outcomes:
~ Describe what a monosaccharide is
and name examples.
~ Explain how to carry out a test for
reducing sugars.
Sunday, 28
September 2014
Keywords
Monomer
Polymer
Monosaccharide
Reducing sugar
Benedict’s

3. Main function in the
body?
Energy
Named examples?
Starch, glucose, glycogen
Carbohydrates?
What enzymes help
to digest them?
Carbohydrases e.g.
amylase
Chemical
elements?
Carbon
Hydrogen
Oxygen

4. Monomers and polymers
Carbohydrates are polymers.
An individual molecule is a
monomer in this case a sugar,
monosaccharide.
Polysaccharide

5. Monosaccharides ~ Sweet tasting,
soluble substances.
~ e.g. Glucose,
C6H12O6
~ Fructose and
galactose
~ respiration

6. Biochemical test
• All monosaccharides and some disaccharides are
reducing sugars.
Reduction reaction involves electrons being gained.
The reducing sugars donate electrons to another
chemical, copper (II) sulphate or Benedict’s
solution.
 Forming red
precipitate of copper (I)
oxide

7. Test for reducing sugars
1. Add 2cm³ of
food sample (in
liquid form) to a
test tube.
2. Then add 2cm³ of
Benedict’s Reagent.
3. Heat mixture in
gentle boiling
water bath for
5mins.
Benedict’s Test
[Reducing
sugar]
Results
Colour of
solution and
precipitate
None Blue
Very low Green
Low Yellow
Medium Brown
High Red

8. Useful Link
www.biochemistry.org
Downloadable biochemistry booklets