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Chapter 2 Microorganisms Friend and Foe Notes

WHAT IS MICROORGANISMS ?

Definition of Microorganism: living organisms around us which cannot be seen by naked eyescalled microorganism or microbes. We need a microscope to see microbes.

HOW MANY TYPES OF MICROORGANISMS ARE THERE:

There are five major groups of micro-organisms as given below:-

  1. BACTERIA
  2. ALGAE
  3. PROTOZOA
  4. FUNGI
  5. VIRUSES
HOW MANY TYPES OF MICROORGANISMS ARE THERE

IMPORTANT POINTS ON BACTERIA:

  1. Mostly single celled organism.
  2. Lived together in colonies of millions.
  3. Found in basically 3 different shapes:
  • Rod shaped(bacilli)
  • Spherical shaped (cocci).
  • Spiral (spirillia).

IMPORTANT POINTS ON ALGAE

  • Simple plant like structure organism.
  • Aquatic in nature.
  • It can be unicellular or multicellular.
  • Ex: chlamydomonas, seaweed, diatoms.

IMPORTANT POINTS ON PROTOZOA

  • Unicellular microorganism.
  • Mostly aquatic in nature.
  • Ex- amoeba, paramecium etc.

IMPORTANT POINTS ON FUNGI

  • Plant like organism that do not contain chlorophyll
  • Can be unicellular or multicellular. Ex- yeast, rizopus etc.

 

IMPORTANT POINTS ON VIRUSES

  • Smaller than any other known cell.
  • It can reproduce only inside living bodies, means they need a host.
  • It is a borderline between a living and non living thing.
Types of Viruses

WHERE  DO  MICROORGANISMS LIVE?

Microbes can survive in all kinds of environments –

  1. In any kind of temperature:- from icy cold climates to hot springs.
  2. In any humidity level:- deserts to marshy lands.
  3. Some live independently while others live as parasites means inside the bodies of other organisms including animals and human beings.

MICROORGANISMS AND US:

Some of Microorganisms are beneficial in many ways while some others are harmful and cause diseases.

FRIENDLY MICROORGANISMS:-

Microorganisms are used for various purposes like:-

  1. Some microorganisms are used in the production of curd, bread and cake.
  2. Microorganisms have been used for the production of alcohol since ages.
  3. They are also used in cleaning up of the environment as composers. For example, the organic wastes (vegetable peels, remains of animals, faeces, etc.) are broken down into harmless and usable substances by bacteria.
  4. In agriculture fields, microorganisms are used to increase soil fertility by fixing nitrogen.

Commercial Use of Microorganisms:

  • Microorganisms are used for large scale production of alcohol, wine and acetic acid i.e Vinegar.
  • For commercial production of alcohol and wine, yeast is grown on natural sugars present in grains like barley, wheat, rice, crushed fruit juices, etc.

Medicinal Use of Microorganisms:

  • Some antibiotic tablets, capsules or injections like penicillin are prepared with the help of microorganisms.
  • These medicines produced from Bactria and fungi stop the growth of pathogens or kill them Such medicines are called antibiotics.
  • Microorganisms are also used to control many plant diseases.

WHAT PRECAUTIONS SHOULD BE FOLLOWED WHILE TAKING ANTIBIOTICS AND WHY?

Precautions for using antibiotics: –

 (i)Antibiotics should be taken only on the advice of the qualified doctor.

 (ii)One must complete the course prescribed by the doctor.

 (iii)Antibiotics should not be taken when we are suffering from a viral disease because antibiotics are not effective against disease-causing viruses.

 Antibiotics taken in wrong doses may make the drug less effective when we might need it in future. Moreover, antibiotics taken unnecessarily may kill the beneficial bacteria in the body.