Watch the following video about organic compounds and
answer the following questions.
https://www.youtube.com/watch?v=nt9u7CfVoc4
1. Name the four molecules of life and their functions.
2. Name the elements found in the molecules of life.
2 of 30
© Boardworks Ltd 2008
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What are biomolecules?
 Organic compounds are chemical
substances that:
 Make up organisms
 Help organisms carry out life processes
 All contain the elements carbon &
hydrogen
 Carbon is the major element
Something for you to do?
In groups, find out 3 significance of carbon.

I. Carbon is the most
important element in
living things because of its
special properties.
 A.
Carbon can form bonds
with itself.
 B.
Carbon can form
molecules with long
chains/ rings of atoms.
 C.
Many molecules found
in living things (like DNA,
sugars, fats, and proteins)
are LARGE molecules
containing chains of
carbon.

Six elements form most
molecules in living things:
Phosphorus Nitrogen
Carbon Hydrogen Oxygen
Sulfur
Please Never Call Her On
Sunday
a
molecule that is
produced by a living
organism.
 present in organisms
 essential to biological
processes, such as cell
division, morphogenesis,
or development.
 Carbohydrates
are made
from the elements carbon
(C), oxygen (O) and
hydrogen (H), bonded on
a ration of 1:2:1.
Something to think about
Provide 3 functions of
carbohydrates in living
organisms.
They are used to:
 store energy – starch in plant
cells; glycogen in animal
muscle cells
 provide energy – during
cellular respiration in the
mitochondrion
 provide structure and
protection –through cellulose
 They
are used to:
 store energy – starch in
plant cells; glycogen in
animal muscle cells
 provide energy – during
cellular respiration in the
mitochondrion
 provide structure and
protection – cell wall in
plant cells.
 Monosaccharides
are
single ring structures
 Glucose
is the basic
building block of all
carbohydrates.
 Examples
glucose (C6 H12 O6),
fructose (C6 H12 O6),
galactose (C6 H12 O6)
Polymers: large molecules are made up of long
chains of single units called polymers.
The single units are called monomers.
 Two
monosaccharides
bonded together form a
disaccharide.
 One water molecule is
removed to form a
disaccharideCondensation reaction/
Dehydration synthesis
 Sucrose
 Maltose
 Lactose
(table sugar)
(dough sugar)
(milk sugar)
Glycosidic bond
Glucose + glucose  maltose + water
Glucose + fructose  sucrose + water
Glucose+ galactose  lactose+ water
 More
than two monosaccharides bond
together by condensation reaction to
form a carbohydrate called a
polysaccharide
 May
contain a thousand
monosaccharides
 They store energy (starch) and form
structural tissues (cellulose,
exoskeletons)
 Polysaccharides
are water
insoluble
 Starch is a form at which
glucose is stored in a
plant.
 When
the plant needs the
energy. Starch is broken
down and glucose is
released through
Hydrolysis, i.e during
cellular respiration
Monosaccharides
Formula
Where found
Fructose
C6 H12 O6
Fruits
Glucose
Galactose , or ribose
C6 H12 O6
Galactose:
C6 H12 O6
From digestion of other carbohydrates
Galactose: milk
Ribose: C5H10O5
Ribose: DNA, RNA
Disaccharides
Formula
Where found
Sucrose
C12 H22O11
Table sugar
Lactose
C12 H22O11
Milk
Maltose
C12 H22O11
Malt sugar
Polysaccharides
Where found
Function
Starch
Potatoes
Used by plants to store energy
Glycogen
In human liver cells
Used by animals to store energy
Cellulose
Cell walls of plants
Used by plants to form rigid walls around cells
Chitin
Exoskeleton of insects
Used by some animals to form an external skeleton
1.
2.
3.
4.
5.
6.
7.
8.
Name the 4 main elements that make up 95% of an organism.
Name the monomers of carbohydrates.
Name the 4 types of bonds carbon can form.
What are macromolecules?
What elements make up carbohydrates & lipids (symbols)?
Differentiate between a monosaccharide, disaccharide and a
polysaccharide.
Differentiate between a glycosidic bond, dehydration synthesis
and condensation reaction.
Name the sugar molecules that form maltose, sucrose and
lactose.
In pairs, complete the following questions.
1. State the difference between a monosaccharide,
disaccharide and polysaccharide.
2. Complete the following reactions
glucose + glucose
----------  maltose + water
glucose
---------- + water
---------- + fructose  sucrose
Glucose+
galactose
-----------------------  lactose+ water
Carbon, Hydrogen, Oxygen, Nitrogen
2. Monosaccharides (glucose, galactose, fructose). Main monomer
is glucose.
3. Single bonds, double bonds, triple bond (sharing of 6 electrons).
4. Macro-molecules: molecules required in large quantities by
living organisms.
5. CHO
6. Monosaccharide: single ring sugar molecules e.g glucose;
Disaccharide: two monosaccharides bonded together form a
disaccharide.
Polysaccharide: More than two monosaccharides bonded together
1.
7. Glycosidic bond: type of covalent bond that joins a sugar
molecule to another group, which may or may not be another
carbohydrate.
 Dehydration synthesis and condensation reaction: a process
of joining two molecules, or compounds, together by
removing water
 Hydrolysis is a chemical process in which a molecule of
water is added to a substance to split it into two parts.
8. Glucose + glucose  maltose + water
Glucose + fructose  sucrose + water
Glucose+ galactose  lactose+ water
Glycosidic bond: type of covalent bond that joins a sugar
molecule to another group, which may or may not be another
carbohydrate.
 Dehydration synthesis and condensation reaction: a process
of joining two molecules, or compounds, together by
removing water
 Hydrolysis is a chemical process in which a molecule of
water is added to a substance to split it into two parts.

Diabetes:
Type1: A chronic condition in
which the pancreas produces
little or no insulin
Type 2: the body either
doesn't produce enough
insulin, or it resists insulin.
Treatments include diet,
exercise, medication and
insulin therapy.
 https://www.youtube.com/watch?v=nt9u7CfVoc4
- song
 https://www.youtube.com/watch?v=jQi84TnstI4 – carbohydrates
 https://www.youtube.com/watch?v=BVxeeiR7JB0 – lipids
Skip 2:58- 5:31; 7:45- 9:15
 https://www.youtube.com/watch?v=HSCUAjZQhXI – proteins
****Take note of the 20 amino acids for Grade 12 Protein
Synthesis
 Contain

carbon, hydrogen, and oxygen
E.g fats, waxes and oils
 Lipid
molecules consist of 1 glycerol & 3
fatty acids

Other types of lipids can contain additional
molecules.
Properties of lipids
 Are they soluble in
water????
 Soluble in alcohol
 All lipids are hydrophobic
Made up of saturated and
unsaturated fatty acids.
What is the difference
between the two?
 1.
Unsaturated fats – liquids
at room temperature –
mainly plant fats
 eg. olive oil, sunflower oil
 2.
Saturated fats – solids at
room temperature – mainly
animal fats
 eg. fat on red meat, butter
 A diet high in saturated fats
cause the formation of
cholesterol in the
 blood which clogs arteries
(artherosclerosis)
 – can lead to heart attack
 Lipids
may consist of fatty acids alone or in
combination with other compounds; several
types of lipids consist of fatty acids combined
with a molecule of alcohol:



Triglycerides are the main form of stored energy in
animals (fat)
Phospholipids membranes surrounding the cells of all
organisms
Steroids (or sterols) have several functions. The sterol
cholesterol makes up cell membranes and plays.
Other steroids are male and female sex hormones
Rich source of energy
 Storage of reserve energy eg. peanuts & seeds
 Structural component of cell membranes – phospholipids
 Provides insulation beneath the skin eg. blubber in seals
 Waterproofing material – waxes in insect & plant cuticles
 Protects major organs eg. heart, kidneys

Type of Lipid
Triglycerides
Saturated
Unsaturated
Phospholipids
Steroids
Characteristics
Main form of stored
energy in animals
Where found
vegetable oil (typically more
unsaturated)
animal fats (typically more saturated)
Animals use these to store energy
Form straight chains
b/c carbon atoms are
bonded to as many H
atoms as possible;
store energy in
compact form; solid at
room temperature
Form bent chains b/c Plants use these to store energy
some C atoms are not
bonded to as many H
atoms as possible;
store energy; liquid at
room temperature
Major component of
Liver, peanuts
cell membranes
Serve as chemical
found in plants, animals, and fungi
messengers and have
other roles
Answer the following questions.
1. State four functions of lipids
2. Name the monomers of lipids
3. Differentiate between saturated and unsaturated fatty
acids
4. What are trans fats? Provide an example
5. Explain the function of lipase
6. Where is lipase secreted in the human body
7. What solution is released by liver to break down lipids?
8. Which fats are healthier between saturated and
unsaturated fats? Explain your answer.
Contain C, H, O, N and P
 Consist of building blocks
called nucleotides
1. DNA – deoxyribonucleic acid
2. RNA – ribonucleic acid
 Biological Importance
- DNA carries and transmits
genetic information
- DNA & RNA control the
metabolic activities of the cell
eg. protein synthesis

 Contain
C, H, O and N
 Some also contain P, S and
Fe
 Consist of long chains of
amino acids
 The number and sequence
of amino acids determines
the characteristics of a
particular protein
There are 20
different types of
amino acids
There are 20
different types of
amino acids
 The
sequence of amino
acids determines the type
of protein
 The bond between amino
acids is known as a
peptide bond.
Peptide bond
There are 20
different types of
amino acids
 Dipeptide
bond- two amino
acids linked by a peptide
bond.
 Tripeptide bond- the bond
between 3 amino acids
 Polypeptide bond – the bond
between many amino acids
 Proteins
are 51+ amino acids
linked by polypeptide bond
Peptide bond
 Biological
Importance :
 Forms body materials eg. Muscle, skin, hair, nails
 Enzymes and hormones are proteins
 Transport eg. haemoglobin transports oxygen in blood
 Protects body eg. Forms antibodies, fibres for blood clots
Study the following diagram and answer the questions.
1. Differentiate between organic and inorganic compounds
2. Identify the type of organic compound represented by A, B and
C, respectively.
3. Name the compound formed by the two glucose molecules on
A.
4. Identify the type of bond indicated by X.
 are
globular proteins
 Biological functions
 biological catalysts i.e.
speed up the rate at
which metabolic reactions
occur in living organisms
 maintains reactions at an
optimum rate
 catalyze the synthesis and
breakdown of molecules
 For
a reaction to
happen it needs
activation energy
 Enzymes lower the
activation energy of a
reaction
 Therefore accelerating
the reaction.
 Chemical
reactions in
living cells are known
as metabolic
reactions.
 There are two types
of metabolic
reactions:
 Anabolic reactions
 Catabolic reactions
 For
a reaction to happen it needs activation energy
 Enzymes lower the activation energy of a reaction
 Therefore accelerating the reaction.
Disaccharides
maltase
maltose + water---------- glucose + glucose
sucrase
sucrose + water -----------
glucose + fructose
lactase
lactose + water ---------- glucose + galactose
Polysaccharides
amylase
starch+ water ----------
maltose
 During
digestion, complex molecules are broken into simpler
molecules by using water.
 This catabolic process is known as HYDROLYSIS
Lipid
lipase
Lipid + water ----------
3 fatty acids + 1 glycerol
Protein
Protease
proteins+ water ----------
smaller polypeptides, amino acids
e.g. pepsin
A
substance that an enzyme acts on is called a substrate.
 A substance formed during the reaction is the product.
 Enzymes are substrate specific
 Enzymes remain unchanged in a chemical reaction
maltase
maltose + water----------
glucose + glucose
Lock & key theory
1.
2.
3.
4.
5.
6.
Identify the parts numbered 1-5.
Define enzyme.
Is the reaction illustrated above anabolic or catabolic?
Provide a reason for your answer.
What is the function of part numbered 2?
Which numbered part is specifically affected by change in
pH?
Give an explanation of how part numbered 2 is affected by
changed in pH.
 Enzymes
1.
2.
3.
4.
5.
are sensitive to temperature
and pH
function best (optimum rate) at
an optimum temp (30◦C-40◦C) &
pH (substrate specific)
exposure to extreme temp
(45◦C) & pH denatures enzyme
low temperatures inactivate
enzymes
Can be used over and over
again
 1.
‘Biological’ detergents –
contain protein-digesting
enzymes (proteases) to break
down stains eg. blood, sweat,
gravy, egg yolk
 2. Brewing industry – beer
making
 3. Dairy industry – cheese
making
 4. Food industry – fruit juices
 5. Baking industry –bread making
1.
2.
3.
4.
State the optimum
temperature for the
enzyme.
What amount of food is
broken down at 25◦C?
Give an explanation for
the shape of the graph
between 5◦C and 35◦C.
State 4 properties of
enzymes.
The graph below shows the
effect of temperature on
enzyme activity
The graph below shows the
effect of temperature on
enzyme activity
1.
2.
3.
State the optimum
temperature for the
enzyme.
State the enzyme
activity at:
a. 20◦C
b. 40◦C
c.50◦C
Briefly explain what
happens to the enzyme
activity once it reaches
its optimum
temperature
Make use of a labelled diagram to prove that enzymes are
substrate specific.
 Contain
C, H, O and N,
also S, P – complex
organic compounds
 Required in small
quantities for normal
growth and development
in animals
1.1 List the nutrient that is required
for :
a. developing muscle tissue
b. maintaining good eye-sight
c. maintaining salt-water balance
1.2 State the deficiency disease if
there is a lack of
a. vitamin B1
b. iron
1.3 If a person ate 4 slices of bread
for lunch calculate the amount (in
g) consumed of the following :
a. Protein
b. Sugar
The table below indicates the nutritional information on
the packaging of a loaf of brown bread.
Composition
(elements
present)
Carbohydrates
Lipids
Nucleic acids
1 Function
1 Example
Monomer
Composition
(elements
present)
Carbohydrates
Function
Examples
Monomer
1.
2.
3.
4.
Which of these food types are
least suitable as a source of
insulation? Give a reason.
Which of these food types are
most suitable for structural
growth? Give a reason.
Give a reason why food type
C is the richest source of
energy.
What percentage of food type
B is fat?
1.
2.
3.
Name the main component
of food type C.
List 3 nutritional function
of the component
mentioned in no.1
What type of food (A, B, C
or D) will be the most
beneficial to a person that
lives in a very cold place
such as Antarctica? Give a
reason.
1.
2.
3.
a)
b)
c)
Identify each compound (A, B & C). Give a reason for your answer.
Name the monomers of compound C.
Which compound (A, B or C)..
is involved with the formation of the large, insoluble compounds
that are needed for the formation of plant cell wall?
may form part of enzyme?
Is used as main energy source in respiration?
1.
a)
b)
c)
d)
Give the names of the
following:
Enzyme A
Compound B
Molecule C
Enzyme X