Microorganisms, also known as microbes, are tiny organisms that can only be seen with a microscope. They include bacteria, fungi, algae, protozoa, and viruses. Microorganisms are found everywhere and can be beneficial or harmful. Beneficial microorganisms are used in food production and agriculture, while harmful microorganisms can cause diseases. Microorganisms undergo life processes like growth, movement, and respiration. They need food, water, and suitable temperatures to survive. Understanding microorganisms and how to prevent the spread of disease is important.

1. MICROORGANISMS
• also known as microbes
• so tiny that it cannot be
seen with our naked eyes
• is the smallest organism
(living things) that can only be seen through a
microscope
• but a magnifying glass can be used to observe
certain microorganism such as yeast
• undergo life processes as it grow, breathe,
moves and propagate (propagate means it will
increase in numbers)
• can be harmful and some are useful
• can be found in air, water and soil as well as
on or in human bodies or animals
• the study of microorganisms is known as
microbiology
• to overcome our eyes limitation
by using microscope and
magnifying glass
Types of Microorganisms
(a) Fungi (singular is ‘fungus’)
• the largest microorganism
• do not have chlorophyll to make own food
so they have to get their nutrients from a
host, either on living or dead organisms as
well as in water, trees, soil, air and rotten
foods
• grow on lots of different hosts, anywhere
that is warm and damp
• examples that are very familiar include
moulds, yeast and mushrooms
• yeast are single-celled fungi that eat
starches and sugars and used to make
bread and other wheat-based products,
such as pizza dough and dumplings
Yeast Cells
Moulds Mushrooms
Yeast Cell Structure
(b) Bacteria (singular is ‘bacterium’)
• do not have chlorophyll to make own food
• get food from live and dead organisms
• can be found in air, water, soil, food and in
living or dead organisms
• under the group of living microorganisms,
bacteria are a major group because
bacteria can grow extremely rapid
• flagellum (plural is flagella) is a hair like
structure used by bacteria to swim but if
bacteria don’t have flagella, they need
water, wind, passing animals or you to
spread them around
• exist in a different shapes, sizes and
colours

2. Bacterial Shapes & Arrangements
Coccus (Plural - Cocci)
Bacillus (Plural - Bacilli)
Bacterial Shapes & Arrangements
)
Curved Forms
(c) Algae
• small plants living in
water;
• contains chlorophyll
to make its own
food;
• lives in pond, lakes, oceans and
other mist habits.
• Examples of algae in nature; green algae,
blue-green algae, fibrous green algae, red
algae, seaweed and kelp
Flagellum helps in its movement
Curved Forms
small plants living in
contains chlorophyll
to make its own
lives in pond, lakes, oceans and in many
other mist habits.
Examples of algae in nature; green algae,
green algae, fibrous green algae, red
algae, seaweed and kelp
Flagellum helps in its movement

3. (d) Virus
• the tiniest /
smallest
microorganism
• can be only
observed under
electron microscope
• considered as a living and non-living
things because they don’t carry life
processes like breathing and eating
except for reproduction
• can’t produce on its own and thus gets its
food from live organism only
• by entering a living body, it uses material
from the host to reproduce more viruses;
• can be found in some humans, animals,
plants and also in protozoa, fungi and
bacteria (a phage is a virus which attacks
bacteria)
(e) Protozoa
• larger than bacteria and viruses
• found mainly in ponds, rivers, swamps and
body tissue fluid
• can make food or feed from the cell of
dead or living organisms and some of them
feed on other microorganisms
• harmful protozoa are found in raw
vegetables that grow in polluted water
supplies
Paramecium uses its cilia to move
Amoeba moves by extending pseudopodium or
false feet

4. Life Processes of Microorganisms
(a) Microorganism Breath
• microorganisms breath to survive
• they take in oxygen (from the air) and
produce carbon dioxide
• yeast (fungus) breath in the process of
bread making. When yeast breathes, it
takes in oxygen and gives out
dioxide. The carbon dioxide gas that is
given out by yeast causes the dough to rise
and become bigger
Experiment 1.1
Purpose:
To examine that microorganism breathe.
Materials:
A cup of flour, half cup of warm water, a teaspoon
of dried yeast, a teaspoon of sugar and a damp
cloth.
Procedure:
1. All ingredients are mixed and kneaded well to
form dough.
2. The dough is covered with a dam cloth and left
aside for about one hour at room
temperature.
3. The above steps are repeated but this time the
dried yeast are left out.
Observation:
1. Dough with dried yeast successfully rises.
2. Dough without dried yeast failed to rises.
A) Dough without dried yeast
B) Dough with dried yeast added
Conclusion:
1. Yeast breathes and gives out carbon dioxide gas.
2. The gases produced occupy space in the dough
causing the dough to rise and become bigger.
(b) Microorganism Growth
• microorganisms also grow and reproduce
like other living things under suitable
conditions
microorganisms breath to survive
hey take in oxygen (from the air) and
in the process of
east breathes, it
gives out carbon
dioxide. The carbon dioxide gas that is
the dough to rise
breathe.
A cup of flour, half cup of warm water, a teaspoon
of dried yeast, a teaspoon of sugar and a damp
All ingredients are mixed and kneaded well to
The dough is covered with a dam cloth and left
t one hour at room
The above steps are repeated but this time the
Dough with dried yeast successfully rises.
Dough without dried yeast failed to rises.
A) Dough without dried yeast
yeast added
Yeast breathes and gives out carbon dioxide gas.
The gases produced occupy space in the dough
causing the dough to rise and become bigger.
icroorganisms also grow and reproduce
under suitable
• to grow well, microorganisms need
food, water and a suitable temperature
• they grow faster in moist and warm
conditions
• when microorganism grows on food
food turns bad
damaged
• if we leave a bowl o
will be covered with white patches
and they grow bigger after some times
• fungi also grow on rotten fruit and bread
when conditions are suitable for them
Experiment 1.2
Purpose:
To investigate that microorganisms grow.
Materials:
A slice of bread, some water, plastic bag and
magnifying glass.
Procedure:
1. A few drops of water are sprinkled on the slice
of bread.
2. The bread is kept in a plastic bag and placed in
a dark place in the science laboratory.
3. Observe the changes o
bread cupboard under the magnifying glass for
three days.
Observation:
The numbers of black patches on the bread
increase from day one until day three.
Microorganisms grow
Conclusion:
1. Drops of water and laboratory environment
may contain microorganisms.
2. Microorganisms will only grow when food,
water, oxygen ad a suitable temperature are
available.
o grow well, microorganisms need air,
and a suitable temperature
they grow faster in moist and warm
when microorganism grows on food, the
food turns bad and it’s considered as
if we leave a bowl of rice for a few days, it
will be covered with white patches (fungi)
grow bigger after some times
ungi also grow on rotten fruit and bread
onditions are suitable for them
To investigate that microorganisms grow.
A slice of bread, some water, plastic bag and
A few drops of water are sprinkled on the slice
The bread is kept in a plastic bag and placed in
a dark place in the science laboratory.
Observe the changes on the surface of the
bread cupboard under the magnifying glass for
The numbers of black patches on the bread
increase from day one until day three.
Microorganisms grow
Drops of water and laboratory environment
ontain microorganisms.
Microorganisms will only grow when food,
water, oxygen ad a suitable temperature are

5. (c) Microorganism Movement
• microorganisms can move on their own to
survive
• some microorganisms are immobile, which
mean that they are not able to move
• in addition some microorganisms do not
have legs but can move freely by using
special features or
structure in the body
such as flagella, cilia or
extended false feet
(pseudopodium)
• different microorganisms move in different
ways and can easily be observe through a
microscope
Experiment 1.3
Purpose:
To observe the movement of microorganisms.
Materials:
Some pond water, microscope, glass slide, and a
dropper.
Procedure:
1. Samples of water are collected from the
ponds.
2. Drops of water were placed on a glass slide.
3. Movement of microorganisms were observed
under the microscope.
Slide preparation.
Observation:
A lot of tiny microorganisms are seen moving in
the water sample.
an move on their own to
ome microorganisms are immobile, which
able to move
n addition some microorganisms do not
have legs but can move freely by using
ifferent microorganisms move in different
be observe through a
To observe the movement of microorganisms.
Some pond water, microscope, glass slide, and a
Samples of water are collected from the
placed on a glass slide.
Movement of microorganisms were observed
A lot of tiny microorganisms are seen moving in
Paramecium and Amoeba movement
Conclusion:
1. The movement of microorganisms are
observed in the ponds water.
2. Different microorganism move in different
ways.
Useful microorganisms
(a) Used in food production or food industry
Useful Explanation
Yeast used to make bread dough
rise and the bread fluffy
used to make tempe (soy
bean, wheat and water
mixed with yeast)
used to make tapai
(glutinous rice or tapioca
mixed with yeast
few weeks, its turn to
sweet and soft tapioca or
glutinous rice)
used to produce wine by
fermenting
as grape juice
involved in producing
alcoholic drinks
Mushrooms eaten as food (
is a mushroom called
‘amanita’ which is
poisonous)
Bacteria used
fermented food such as
vinegar and wine
can turn milk into cheese
and yogurt
Paramecium and Amoeba movement
The movement of microorganisms are
observed in the ponds water.
Different microorganism move in different
Used in food production or food industry
Explanation
used to make bread dough
rise and the bread fluffy
used to make tempe (soy
bean, wheat and water
mixed with yeast)
used to make tapai
(glutinous rice or tapioca
mixed with yeast and after
few weeks, its turn to
sweet and soft tapioca or
glutinous rice)
used to produce wine by
fermenting fruit juices such
as grape juice
involved in producing
alcoholic drinks
eaten as food (note: there
is a mushroom called
‘amanita’ which is
poisonous)
sed in the preparation of
fermented food such as
vinegar and wine
can turn milk into cheese
and yogurt

6. (b) Used to produce antibiotics
• drugs made from fungi cure
diseases and stop the
rejection of transplanted
hearts and other organs
• Penicillin, an antibiotic (a drug that kills
bacteria) is made from a fungus
Flemming was the founder)
(c) Used in agriculture industry
• some fungi and bacteria are useful for
breaking down the waste matter or
remains of plants and animals
organic fertilisers
• organic gardeners and farmers use fungi to
kill pests
• algae helps the environment by
oxygen photosynthesis
Harmful microorganisms
Causes Explanation
illnesses or
diseases
microorganisms that enter
the body will grow and
produce toxins that cause
illnesses or diseases
e.g. measles, mumps,
(German measles
(Acquired Immune Deficiency
Syndrome))
food poisoning shows some symptom such as
vomiting, stomach ache,
nausea (dizziness) and
diarrhoea
food to turn
bad
food becomes contaminated
and this spoilage food gives
out a foul smell, bad tastes
and bad texture
tooth decay occurs when a hole formed
when the acid produced by
the bacteria (that
with sugar in our food)
dissolves the surf
tooth
Penicillin, an antibiotic (a drug that kills
fungus (Alexander
ome fungi and bacteria are useful for
breaking down the waste matter or
remains of plants and animals to produce
organic gardeners and farmers use fungi to
lgae helps the environment by creating
microorganisms that enter
the body will grow and
produce toxins that cause
illnesses or diseases
measles, mumps, rubella
German measles) and AIDS
(Acquired Immune Deficiency
shows some symptom such as
vomiting, stomach ache,
zziness) and
food becomes contaminated
and this spoilage food gives
out a foul smell, bad tastes
occurs when a hole formed
when the acid produced by
that interact
with sugar in our food)
dissolves the surface of the
• microorganisms that cause disea
pathogens (gems)
• disease that can be spread from person to
another person called contagious diseases
• diseases are normally spread by:
o taking in contaminated food
poisoning)
o taking in contaminated drink
o direct contact with infected people
(measles, chickenpox)
o coughing or sneezing into the air
cough)
o small animals such as flies, mosquitoes and
rats (malaria, dengue, cholera)
Ways to prevent spreading of
• wash hands before handling food
• wash hands after using the toilet
• drink boiled water and eat well cooked food
• cover your mouth
coughing or sneezing
• cover food or keep in the refrigerator to
prevent contamination by bacteria or insects
• apply antiseptic on wound
• not spitting in public areas
• some diseases can be prevented by
vaccination or immunisation
• quarantine the patients who are suffering
from contagious diseases such as chickenpox,
conjunctivitis or mumps
• not sharing personal items such as towels,
toothbrushes and combs with infected person
• controlling the breeding sites of mosquitoes,
cockroaches and flies
t cause diseases are called
isease that can be spread from person to
another person called contagious diseases
iseases are normally spread by:
taking in contaminated food (food
taking in contaminated drink (cholera)
ntact with infected people
(measles, chickenpox)
coughing or sneezing into the air (flu and
small animals such as flies, mosquitoes and
(malaria, dengue, cholera)
spreading of diseases
ash hands before handling food
sh hands after using the toilet
boiled water and eat well cooked food
mouth/nose when you are
sneezing
food or keep in the refrigerator to
contamination by bacteria or insects
on wound to prevent infection
t spitting in public areas
ome diseases can be prevented by
vaccination or immunisation
uarantine the patients who are suffering
from contagious diseases such as chickenpox,
conjunctivitis or mumps
ot sharing personal items such as towels,
othbrushes and combs with infected person
ontrolling the breeding sites of mosquitoes,
cockroaches and flies