Title
Process
Introduction to
Biological Molecules
GCSE Prior Knowledge Pop Quiz
Carbohydrates
Glucose Isomers
Reactions
Lesson Assessment
Wipeout
Outcomes
Identify/State…
some biological polymers, and the
monomer from which they are made
Describe/Explain/ Apply…..
• what a monomers and polymers are
Benefits
Develop ideas about the
importance of
biological molecules
• the concept of condensation and
hydrolysis reactions in
forming/breaking down polymers
Trust . Respect . Forgiveness . Compassion . Peace
Prior Knowledge
Life Based on Carbon
Carbon atoms readily form bonds with other carbon
atoms. This allows a sequence of carbon atoms of different
lengths to be built up. These form a ‘backbone’ along
which other atoms can be attached.
Know your prefixes!
Prefix
Number
Mono
1
Di
2
Tri
Tetra
3
Penta
5
Hexa
6
Poly
Many
4
Monomers and Polymers
Monomer – one of many small molecules that combine to form a
larger one (a polymer)
Polymer – large molecule made up of small repeating units
(monomers)
Biological molecule
Carbohydrate
Proteins
Nucleic acids
Monomer
Monosaccharide
Polymer
Polysaccharide
Amino Acids
Proteins and Polypeptides
Nucleotide
DNA
Carbohydrates
In carbohydrates, the basic monomer is sugar – otherwise known as
a saccharide.
What would a single monomer be called?
What would a pair of monomers be called?
What would a large chain of monomers be called?
Monosaccharides
Monosaccharides are sweet-tasting, soluble substances
with the general formula (CH20)n where ‘n’ can be any
number between one and seven.
Examples – glucose, galactose and fructose
Glucose is a hexose sugar – what does this mean?
What would the formula be for a
pentose sugar?
Glucose
Isomers are molecules with the same molecular formula as
each other, but with the atoms connected to each other in
a different way.
Drawing α-glucose
1. Draw a hexagon with 5 carbon atoms and 1 oxygen atom
2. Add a H20 at each C
3. Add the remaining CH2
Drawing β-glucose
Β-glucose has the same formula as α-glucose, but there is
one difference between the two…
Glucose Isomers
Disaccharides
When combined in pairs, monosaccharides form
disaccharides.
Condensation
Reaction
Glycosidic
Bond
Monosaccharides
Disaccahride
Glucose + Glucose
Glucose + Fructose
Maltose
Sucrose
Glucose + Galactose
Lactose
Condensation Reactions
When combined in pairs, monosaccharides form
disaccharides.
Condensation
Reaction
Glycosidic
Bond
Hydrolysis Reactions
Polymers and disacchairdes can be broken down into
monomers by hydrolysis reaction (breaking the chemical
bond using a water molecule)
Hydrolysis
Reaction
Biological Molecules
Keywords
•
•
•
•
•
•
Glucose
Maltose
Hydrolysis
Condensation
Gylcosidic
Monosaccharide
Biological Molecules
Research the biochemical tests for reducing
sugars, non-reducing sugars and starch.
α- glucose
Carbon atoms
have four
bonds
A condensation
reaction joins two
molecules and a
molecule of water
is released
Glucose +
Fructose 
Sucrose
A condensation
reaction breaks
the chemical
bond using water
The prefix for
‘8’ is poly
α- glucose
Glucose +
Galactose 
Lactose
DNA is a
monomer for
nucleic acid
Fructose is a
monosaccharide
α-glucose and
β-glucose are
isomers of each
other
Glucose +
Glucose 
Sucrose
Introduction to Biological Molecules
Amino acids
are examples
of monomers
The general
formula for a
monosaccharide
is (CH20)n
Monosaccharides
are sweet-tasting
Maltose is a
disaccharide
Values
1
10
2
20
3
30
4
40
5
50
6
60
7
70
8
80
9
90
10
100
11
110
Next
Fish – Dog - Elephant
Glucose(C6H12O6)combines with
fructose(C6H12O6)to form sucrose.
What is the formula of sucrose?
What is the biochemical test
for starch? What does a
positive result look like?
What is reduction?
Title
Process
Testing for Reducing and
Non-reducing Sugars
Fish – Dog – Elephant
Hands Up
Risk Assessment
Benedict’s Test
Analysis
Outcomes
Describe/Explain/ Apply…..
• How to test for reducing sugars,
non-reducing sugars and starch
CPAC – 1a,3a,3b and 4a
Benefits
Develop ideas about the
importance of
biological molecules
Atf – use qualitative reagents to
identify biological molecules
Trust . Respect . Forgiveness . Compassion . Peace
Hands Up
What is the general name for a small unit from which
larger molecules are made?
Glucose
Polymer
Monomer
Starch
Hands Up
What is the name of the monomer which is used
to form proteins?
Amino Acid
Monosaccharide
Nucleotide
Glucose
Hands Up
What is the name of the monomer which is used
to form DNA and RNA?
Amino Acid
Monosaccharide
Nucleotide
Glucose
Hands Up
What kind of reaction joins smaller molecules to
make larger molecules?
Hydrolysis
Condensation
Glycolysis
Hands Up
What kind of reaction involves the addition of
water?
Hydrolysis
Condensation
Glycolysis
Hands Up
What kind of reaction breaks a chemical bond?
Hydrolysis
Condensation
Glycolysis
Hands Up
What kind of reaction involves the elimination of
water?
Hydrolysis
Condensation
Glycolysis
Hands Up
What kind of reaction breaks larger molecules into
smaller molecules?
Hydrolysis
Condensation
Glycolysis
The Benedict’s Test
All sugars can be classified as reducing or non-reducing.
All monosaccharides and some disaccharides are reducing
sugars.
A reducing sugar is a sugar
that can donate electrons to
(or reduce) another
chemical, in this case,
Benedict’s reagent.
Benedict’s reagent is an alkaline solution of copper (II) sulphate.
When a reducing sugar is heated with Benedict’s reagent it forms an
insoluble red precipitate of copper (I) oxide.
The Benedict’s Test
CPAC STATEMENT ASSESSED
1
3
Follows written
procedures
Safely uses a range of
practical equipment
and materials
a. Correctly follows instructions to carry out experimental
techniques or procedures.
a. Identifies hazards and assesses risks associated with
these hazards, making safety adjustments as
necessary, when carrying out experimental
techniques and procedures in the lab or field.
b. Uses appropriate safety equipment and approaches to
minimise risks with minimal prompting.
4
Makes and records
observations
a. Makes accurate observations relevant to the
experimental or investigative procedure.
The Benedict’s Test
Complete a risk assessment for this biochemical test
Hazard
Benedict’s Solution
(low hazard)
Food – Biohazard
Spillages
Burns
Risk
Control Measures
Actions
The Benedict’s Test
Complete a risk assessment for this biochemical test
Hazard
Risk
Control Measures
Actions
Benedict’s Solution
(low hazard)
Low
• Wear PPE
• Use a water bath to
prevent spitting
• Clear up spillages
with a damp cloth
Food – Biohazard
Low
• Do not taste foods in • Seek medical
laboratories; avoid
advice
using products
containing peanuts
etc if there is a known
allergy
Burns
Low
• Use a water bath to
prevent spitting.
• Wear PPE
• Cool any burnt
skin with gentlyrunning tap water
for 10 minutes.
The Benedict’s Test
Order: Biochemical Tests for Carbohydrates
Student Sheet
Take pictures for lab books
Biochemical Tests
Keywords
•
•
•
•
•
Benedict’s
Glucose
Qualitative
Quantitative
Reducing
Fish – Dog - Elephant
Suggest a way, other than comparing colour
changes, in which different concentrations
of reducing sugar could be estimated
Which monosaccharides make up
lactose?
Define osmosis
Title
Process
Quantitative Tests for
Reducing Sugars
Fish – Dog – Elephant
Practical – Quantitative
Benedict’s Test
Bingo
Outcomes
Find the concentration of an
unknown glucose solution
using the Benedict’s test
CPAC – 3b,4a,4b and 5a
ATf – use qualitative reagents to
identify biological molecules
ATc – serial dilutions
Benefits
Develop ideas about the
importance of
biological molecules
Trust . Respect . Forgiveness . Compassion . Peace
The Benedict’s Test
CPAC STATEMENT ASSESSED
3
Safely uses a range of
practical equipment
and materials
b. Uses appropriate safety equipment and approaches to
minimise risks with minimal prompting.
a. Makes accurate observations relevant to the
experimental or investigative procedure.
4
5
Makes and records
observations
b. Obtains accurate, precise and sufficient data for
experimental and investigative procedures and records
this methodically using appropriate units and
conventions.
Researches, references a. Uses appropriate software and/or tools to process
and reports
data, carry out research and report findings.
The Benedict’s Test
Draw an appropriate table for recording your results for the method
below
Method
• 5ml. of Benedict’s solution is added to each tube.
• The tubes should be heated in a water bath for 3 minutes.
• Record the quantitative results (% light transmission) for each tube.
• Plot a graph of your results (log paper). This is your calibration curve.
• Now carry out the Benedict’s test on your glucose solution of unknown
concentration.
• Use your calibration curve to find the concentration.
The Benedict’s Test
Lab Book
• CPAC/Information sheet
• Table of results
• Calibration Curve
• Describe how you found the concentration of the
unknown glucose solution
Bingo
Draw a 3x3 grid. Fill your grid with 9 of the
keywords.
Bingo
Reducing sugars form this
precipitate when heated with
Benedict’s
Bingo
This is the monomer of protein
Bingo
Benedict’s is an alkaline solution
of…
Bingo
This is the disaccharide of glucose
and fructose
Bingo
This is the monomer of DNA
Bingo
This is the type of bond formed
when two monosaccharides
combine
Bingo
This monomer combines with
glucose to form lactose
Bingo
This molecule is released during a
condensation reaction
Bingo
One of many small molecules that
combine to form a polymer
Bingo
An alkaline solution of copper (II)
sulphate
Bingo
Colour that indicates the presence
of reducing sugars
Bingo
Molecules with the same molecular
formula as each other, but with the
atoms connected to each other in a
different way
Bingo
Disaccharide formed when two
glucose molecules combine
Bingo
Type of reaction that involves the
addition of water
Bingo
Large molecule made up of smaller
repeating units
Bingo
Type of reaction that releases a
water molecule
Fish – Dog - Elephant
Briefly describe a method you could use to
identify the concentration of an unknown
glucose solution
Which monosaccharides make up
sucrose?
Define diffusion
Title
Process
Starch, Glycogen and
Cellulose
Fish – Dog – Elephant
GCSE Prior Knowledge Pop Quiz
Research and Teach
Progress Check
Traffic Light Quiz
Lesson Assessment
Outcomes
Describe/Explain/ Apply…..
the structures of starch,
glycogen and cellulose and
how the properties relate to
its function
Benefits
Develop ideas about the
importance of
biological molecules
Trust . Respect . Forgiveness . Compassion . Peace
Prior Knowledge
Research and Teach
TASK:
Split into groups of three.
Each researchers either Starch, Glycogen or Cellulose.
Create a learning resource to teach the other two in your group.
Include:
 Where the bonds are formed.
 Structure of the polysaccharide.
 Properties of the polysaccharide made.
 Function of each polysaccharide.
 How it’s structure aids its function.
Progress Check
Traffic Light Quiz
True
Not Sure
False
Polysaccharides are
polymers
Starch is mainly found in
liver and muscle cells
Long chains of starch
provide structural support
Cellulose is a polymer of βglucose
This diagram shows βglucose:
Chains of β-glucose are
cross-linked to form
microfibrils which form
cellulose fibres
The diagram below shows
the structure of starch
Glycogen is more branched
than starch and has longer
chains
Starch, Glycogen and Cellulose
Keywords
•
•
•
•
Storage
Branches
Insoluble
Helix
Fish – Dog - Elephant
Explain how the structure of glycogen
is related to its function
Which precipitate do reducing
sugars form when heated with
Benedict’s?
What does ‘hydrophobic’
mean?
Title
Process
Lipids
Fish – Dog – Elephant
Properties and roles of lipids
Triglycerides vs Phospholipids
Biochemical test for lipids
Lesson Assessment
Plenary
Outcomes
Describe/Explain/ Apply…..
How the properties of lipids relate to
their functions
Describe/Explain/ Apply…..
How the structure of lipids relate to
their functions
Benefits
Develop ideas about the
importance of
biological molecules
Describe/Explain/ Apply…..
The biochemical test for lipids
Trust . Respect . Forgiveness . Compassion . Peace
Lipids
Properties of lipids
• They contain carbon, hydrogen and oxygen
• The proportion of carbon to oxygen and hydrogen is
smaller than in carbohydrates
• They are insoluble in water
• They are soluble in organic solvents such as alcohols
and acetone
Lipids
Roles of lipids
• Contribute to the flexibility of cell membranes
• Source of energy
• Waterproofing
• Insulation
• Protection
Lipids
Triglycerides
3
fatty
acids
1
glycerol
What type of reaction is
this?
Lipids
Triglycerides
As the glycerol molecule
in all triglycerides is the
same, the differences in
the properties of fats and
oils come from the
variations in fatty acids.
There are over 70
different fatty acids and
all have a carboxyl (COOH) group with a
hydrogen chain attached.
Lipids
Triglycerides
Triglycerides have a higher ratio of energy-storing carbon-hydrogen
bonds to carbon atoms and are therefore an excellent source of energy.
Triglycerides have low mass to energy ratio, making them good storage
molecules because much energy can be stored in a small volume.
Being large, non-polar molecules, triglycerides are insoluble in water. As
a result their storage does not affect osmosis in cells or the water
potential of them.
As they have a high ratio of hydrogen to oxygen atoms, triglycerides
release water when oxidised ands therefore provide an important
source of water, especially for organisms in dry deserts.
Lipids
Phospholipids
Phospholipids are similar to lipids except for one of the fatty acid
molecules is replaced by a phosphate molecule. Whereas fatty acid
molecules repel water (are hydrophobic), phosphate molecules attract
water (hydrophillic).
Emulsion Test for Lipids
CPAC STATEMENT ASSESSED
1
Follows written
procedures
4
Makes and records
observations
a. Correctly follows instructions to carry out experimental
techniques or procedures.
a. Makes accurate observations relevant to the
experimental or investigative procedure.
Lipids
Keywords
•
•
•
•
•
Triglyceride
Ester
Phospholipid
Hydrophobic
Emulsion
Plenary
Write 5 sentences summarising
today’s topic…
And finally to one word….
Now reduce that to 5 key
words…
End of Unit Assessment: Monomers and Polymers