Microorganisms :- Friend and Foe Video Lecture - Class 8

[Music]
what are micro organisms organisms that
are so small that they can only be seen
through a microscope are called
microorganisms or microbes example a
bread gets grayish white patches during
rainy season
what is micro biology the study of micro
organisms is called microbiology where
do micro organisms live microorganisms
can be found in almost any kind of
environment hot desert polar region
saltwater marshlands and inside other
organisms microorganisms can survive
volcanoes deep sea and even vacuum
classification of microorganisms there
are five major groups of microorganism
these are as follows bacteria algae
protozoan fungi viruses bacteria they
are simple living organisms and are
mostly single tutela tiny organisms but
they live together in colonies of
millions bacteria are found in four
different shapes rod-shaped called
vasila round or spherical shaped called
coxa spiral called spirelli comma-shaped
called Vibrio algae algae are simple
plant-like organisms which are usually
aquatic in nature they contain a cell
wall and chlorophyll and can make their
own food by photosynthesis algae can be
unicellular or multicellular some of the
common examples are diatoms and seaweed
protozoa these are unicellular
microscopic organism similar to animals
that can move about to capture food and
are heterotrophic in nature they are
mostly aquatic in nature amoeba
Paramecium are some examples of protozoa
fungi plant like organisms that do not
contain chlorophyll are called fungi
fungi may be unicellular or
multicellular and are found in warm and
moist places fungi can be heterotrophic
saprophytic or parasitic in nutrition
examples yeast rise ah--this mushrooms
puffballs
viruses viruses are smaller than any
known cell viruses can only be seen with
electron microscope viruses can
reproduce only inside the bodies of
other organisms which mean they need a
host useful microorganisms
microorganisms are useful in food and
beverage industry in making medicines
and vaccines in agriculture and in
cleaning the environment food and
beverage industry bacteria help us in
making certain foods lactobacillus is a
bacterium that sours milk and is used to
make scurred from milk many fungi like
mushrooms and morels are edible which
are rich yeast is commonly employed in
preparing food items like bread cakes
idly dosa Dhokla etc yeast is also used
in breweries for making wines by the
process of fermentation making medicines
and vaccines bacteria and fungi are used
to make medicines called antibiotics the
first antibiotic penicillin was
discovered by Alexander Fleming some
common antibiotics are streptomycin and
tobramycin microbes are used to make
vaccines bacteria and yeast are used in
making vitamin b-complex tablets the
human hormonal called
insulin can also be obtained from
bacteria in cleaning the environment
microbes help to keep our environment
clean by decomposing dead matter they
decomposed substances are recycled as
these get reused from the soil by plants
some bacteria decompose sewage and other
wastes in water in agriculture some
bacteria like Rhizobium blue-green algae
like nostoc live in the root nodules of
plants such as graham pee etcetera these
bacteria absorbed the nitrogen of the
atmosphere and converted into nitrate
which serves as natural
fertilizers for plants hence enhancing
soil fertility nitrogen fixation 78% of
atmosphere is composed of nitrogen but
green plants cannot utilize gaseous
nitrogen gaseous nitrogen needs to be
converted into compounds of nitrogen so
that plants can utilize nitrogen the
process of converting nitrogen into
compounds which can be taken up by green
plants is called nitrogen fixation
following are the main steps of nitrogen
fixation a blue-green algae and some
bacteria like Rhizobium convert gaseous
nitrogen into compounds of nitrogen such
nitrogenous compounds get deposited in
soil be during lighting some of the
nitrogen in atmosphere gets converted
into compounds of nitrogen such
nitrogenous compounds reach the soil
along with rainwater sea
green plants absorb nitrogenous
compounds from soil plants make protein
and various other important molecules
from nitrogen nitrogen reaches the body
of other organisms through food chain
deep a major portion of nitrogen from
animals and plants is removed during
excretion remaining portion of nitrogen
is sent back to the environment when
dead animals and plants get decomposed
nitrogen cycle the cycle of events by
which nitrogen is channelized into the
living world and back to atmosphere is
called nitrogen cycle harmful
microorganisms microorganisms that cause
diseases in human animals and plants are
called pathogens or germs diseases that
can spread from an infected person to a
healthy individual through air water or
direct contact are called communicable
diseases examples common cold chickenpox
aids etc microorganisms also cause
diseases in animals and plants for
examples anthrax is a disease caused by
bacterium and affects human and cattle
a virus causes the dangerous foot and
mouth disease in cattle citrus canker is
a bacterial disease that affects trees
of citrus fruits and is spread by air
rust of wheat is a viral disease that
affects vegetable like bindi and spread
by insects malaria is actually caused by
pathogen called Plasmodium protozoa
which is transmitted by female Anopheles
mosquito dengue is caused by dengue
virus and spread by female Aedes
mosquito preventing the spread of
communicable diseases Oh some simple
methods of limiting the spread of
communicable diseases are to keep the
infected person separated from others
and to advise his slasher to keep a
handkerchief on the nose and mouth while
sneezing foe to keep our environment for
surrounding clean oh never let garbage
collect in the neighborhood
Oh timely vaccination against diseases
should also be taken oh to prevent
mosquitoes from breeding we should not
allow water to collect anywhere in our
neighborhoods food spoilage Oh many
bacteria and fungi grow on food items
and produce certain toxic substances
this makes the food unfit for
consumption consuming such food can
cause a serious illness called food
poisoning food poisoning could be due to
the consumption of food spoiled by some
microorganisms microorganisms that grow
on our food sometimes produce toxic
substances these make the food poisonous
causing serious illness and even death
so it is very important that we preserve
food to prevent it from being spoiled
food preservation processing of food to
prevent their spoilage and to retain
their nutritive value for a period is
called food preservation
food can be preserved using many methods
heating eating food to a high
temperature kills microbes for example
milk and water are boiled to kill
microbes cooling food can be kept in
refrigerator at about 5 C which delays
its spoilage canning canning is done to
package or preserve food or drink by
putting it in sealed airtight containers
salting fruit and vegetables can be
preserved by using salt and then drying
salts prevent the growth of microbes
sweetening excess sugar can also works
on the same principle as solving jams
jellies and squashes are preserved by
this method dry or dehydration
dehydration of food remaining water from
it this stops microorganisms from
growing as they cannot grow without
water chemical preservatives chemicals
like sodium benzoate and sodium
metabisulfite prevent microbial attack
and are often used to preserve jams
sauces and ketchup
[Music]