Viruses are microscopic organisms that can only reproduce inside host cells. They come in various shapes and sizes and can infect animals, plants, and bacteria. Useful microbes are used in food/beverage production, medicine, vaccine production, and environmental cleanup. Harmful microbes can cause communicable diseases in humans and plants via air, water, food, or contact. Antibiotics are drugs that kill germs and cure infections, while vaccines protect against diseases by triggering antibody production without causing illness. Proper vaccination prevents diseases like cholera, hepatitis, smallpox, and tuberculosis.

2. Micro organisms friends
and foe
Chapter 2

3. content
 Classification of Microorganisms
o Virus
o Types & Shapes of Viruses
o Classification of Viruses
o Useful & Harmful Microbes
o Communicable Diseases
✔Examples of Carriers
✔Diseases in Human, Plants and Animals by
Microorganisms
 Antibiotics
 Vaccination

4. viruses
 Viruses are microscopic organisms but they are different
from other microbes because they reproduce only inside the
cells of the host organism (which can be a plant, animal, or a
bacterium).
 Viruses are much smaller than bacteria and come in a wide
variety of shapes and sizes.
 A complete virus particle is known as Virion.
 Viruses are non-cellular, microscopic infectious
agents that can only replicate inside a host cell.
 Virus cannot replicate itself outside the host cell.
 This is because viruses lack the required cellular
machinery.
 Therefore, it enters and attaches itself to a specific
host cell, injects its genetic material, reproduces
by using the host genetic material and finally the
host cell splits open, releasing the new viruses.
 It uses the energy of the host cells for tis purpose

6. Animal virus
• These viruses infect by invading the cells of animals,
including humans
• Ex: Influenza virus, mumps virus, rabies virus,
poliovirus, Herpes virus, etc.
Plant virus
• These viruses infect plants by invading the plant
cells.
• Ex: Potato virus, tobacco mosaic virus, beet yellow
virus, and turnip yellow virus, cauliflower mosaic
virus, etc.
Bacteriophage
• The virus which infects bacterial cells is
known as bacteriophage
• as DNA virus, MV-11, RNA virus, λ phage,
etc.

8. o In food Industry
o In Beverage Industry
o In Medicine Industry
o InVaccine Production
o In Increasing Soil Fertility
o In Cleaning the Environment
Importance of Microorganisms

10. Communicable
DiseasesThese are microbial
diseases (diseases
caused by microbes)
that spread from one
infected person to a
healthy person
through air, water,
food or physical
contact, such as
cholera, chicken pox,
common cold and
tuberculosis.
Carriers: Insects and
animals that carry
disease-causing
microbes and transfer

11. Common diseases & their Modes of Transmission and
Organisms that Cause them
Carriers

12. Common Diseases in Plants
caused by Microbes
Citrus Canker is caused
by Bacteria and spreads
through Air.
Rust of Wheat is caused
by Fungi and spreads through Air
Microorganisms can cause diseases in plants
and reduce crop yield. Some of the plants in
which they cause diseases are:

13. Antibiotics Any drug that kills germs in your body is technically
an antibiotic.
• Control
several
plant
• Antibiotics a
medicines that
help stop
infections
• Cure
microbial
infection
in
animals
• Cure
variety of
diseases
E.G
streptomyci
n,
erythromyci
n
By mixing
antibiotics
with the
fees of
livestock
They do this
by killing the
bacteria or by
keeping them
from copying
themselves or
reproducing
The
word antib
iotic means
“against
life.”

14.  It is important to remember that antibiotics
should be taken only on the advice of a
qualified doctor.
 Also you must finish the course prescribed
by doctor.
 Also antibiotics taken unnecessarily may
kill the beneficial bacteria in the body
What precautions we should take while
taking antibiotics?

15. o With the help vaccine
,the small pox has
completely been
eradicated from the
world.
o These days children are
given immunization
from their childhood to
protect them against
many deadly diseases.
o Diphtheria, Tetanus,
Typhoid, Hepatitis,
Tuberculosis, and Polio
are some of the
diseases against which

16. Some Definitions to Remember:
Pathogens: Disease-causing microbes are called Pathogens.
Antibodies: Antibodies are substances our body produces to fight disease-causing
microbes.
Vaccines: Vaccines are weakened or dead disease-causing microbes that are injected in
our body to trigger the production of antibodies. These antibodies remain in the body for
body for a long time to protect it against any attack of disease-causing microbes.
Vaccination: The process of protecting the body from pathogens with the help of
vaccines is called Vaccination.

17. Name some of the diseases which can be
prevented by vaccines
Some of the diseases that can be
prevented by vaccination are:
•Cholera,
•Hepatitis,
•Smallpox, and
•Tuberculosis.
How do microbes clean up the environment?
Microbes or microorganisms decompose organic waste and dead
remains of plants and animals and convert them into simpler
substances (which can again be used by other plants and animals) by
the process of biodegradation. Thus, they help us in getting rid of
harmful and smelly substances and clean up the environment.

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This Presentation is Prepared by
SavRa
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