The big world of microorganisms, nitrogen cycle, what are microorganisms, types of microorganisms

1. THE BIG WORLD OF

2. TOPIC AT GLANCE…
 What are microorganisms???
 Where are microorganisms found???
 What are various groups of microorganisms???
 How are microorganisms both beneficial and harmful to
us???
 How does food go bad???
 What are the common methods of preserving food???
 What is the role of various microorganisms in nitrogen
cycle in nature???

3. WHAT ARE MICROORGANISMS???
 “Microorganisms” is derived from Greek words
micros (small) and organismos (organisms).
 They are too small and can be seen with the help of
microscope.
 Also called as microbes.
 They can be unicellular (single-celled) as well as
multicellular (multi-celled).
 The study of microorganisms is known as
microbiology.

4. WHERE ARE THEY PRESENT???
 They are found
everywhere– in water, in
soil and in air.
 Dessert soil lack them
because of hot and dry
climate but found near
roots of plants and dead
leaves.
 They have heterotrophic
mode of nutrition.
 Parasitic microorganism
causing diseases in host
are known as
pathogens.

5. TYPES OF MICROORGANISMS
 Bacteria
 Algae
 Protozoa
 Fungi

6. BACTERIA
 Simplest unicellular
organisms.
 Exist singly or in chains
or groups.
 A thick outer wall (spore)
help them to survive in
unfavourable conditions.
 Three types of bacteria:
Bacillus (rod-shaped)
Coccus (spherical-shaped)
Spirillus (spiral-shaped)

7. ALGAE
 Plant-like organisms
having cell walls.
 Contains chlorophyll,
therefore, can make food
through photosynthesis.
 Autotrophs but lack roots,
stem and leaves.
 They can be unicellular
or multicellular.
 Seaweeds are largest
algae.
 They are found in water
bodies and moist places.

8. PROTOZOA
 It means first animal.
 They are unicellular
organisms.
 Exist in water and soil.
 They have various
locomotory organs like
pseudopodia, cilia and
flagella.
 They digest their food
in compartments called
vacuoles.

9. FUNGI
 They have saprophytic
mode of nutrition.
 They obtain nutrients fro
dead and decaying
organic matter.
 Examples:
Mushroom (Agaricus)
Moulds (Rhizopus)
Yeast (Unicellular Fungi)

10. VIRUS
 Virus means poison in Latin.
 They can be helpful as well as harmful.
 They are the link between living and non-living.
 They are alive only when it enters cells of a living
plant or animal energy of the host cell to remain
alive.

11. FRIENDLY MICROORGANISMS
 Microorganisms play vital role
in our lives.
 Ways in which they are
beneficial to us:
In decomposition and recycling
In increasing soil fertility
In food chains
In food-making processes
In water treatment plants
In production of energy-giving
fuels
For making antibiotics
For making vaccines
In science and technological
fields

12. HARMFUL MICROORGANISMS
 Microorganisms more than the harm the y cause to us than for
their uses.
 Microorganisms causing diseases are called pathogens.
 They make their way into our body through the following ways:
Through air
Through food and water
Through direct contact
Through carriers
Through cuts and wounds on skins

14. FOOD PRESERVATION
 The process of treatment food to slow down or to
stop the growth of microorganisms that spoil food is
known as food preservation.
 Food spoilage by microorganisms is a disagreeable
change in food.
 Common methods of food preservation:
Using natural preservatives (salt)
Using food grade chemical preservation (heating)
By refrigeration and freezing (pasteurization)
By drying and dehydration (canning)

15. NITROGEN CYCLE
Nitrogen cycle is a cycle in which atmospheric
nitrogen is converted from its gaseous form into
usable form and returned to the atmosphere
through stages that involves microorganisms.

16. STAGES OF NITROGEN CYCLE
 Nitrogen fixation
 Nitrogen assimilation
 Ammonification
 Nitrification
 Denitrification

17. OVERVIEW

19. THANK YOU
Made by:
Rahul Chawla
VIII B