MICROORGANISMS FACTS!

MICROORGANISMS

These are of different kinds in the living world.Organisms that can only be seen under microscope are called microorganisms.The science that deals with the study of microorganisms is called microbiology.microorganisms are found every where and hence account for half of total weight of all living beings on earth!The type of microorganisms are-bacteria,algae,fungi,protozoa,viruses.

Bacteria-The averagesize of a bacterium is 1.25u in diameter(1u=1/1000 m).Almost 250 crores of bacteria may be present in one gram of gardern soil.

Types –On the bases of shapes the bacteria are of 4 types-baccilus,coccus,spirillum and vibrio.Depending on their reactions to stain bacteria may be divide into gram negative or gram positive bacteria.when stained with crystal violet and iodine solution followed by a wash with acetone ,the bacteria without an outer membrane retain stain deep violet these were called gram positive bacteria.the bacteria with an outer membrane could not retain the stain and became colorless .these were called gram negative bacteria.The outer membrane is made of lipopolysaccharide.

Algae-The size of an algae varies from 1 micron for microscopic algae and to several metres for sea weeds.

Types-Algae are classified on the bases of pigments present in them.Green algae -have only chloroplast.eg.Spirogyra.Blue green algae-They include phycocyanin,a blue pigment in addition to chloroplast.eg.Nostoc.Red algae-They include phycorythin,a red pigment in addition to chloroplast and phycoccain.Brown algae-They include fucoxanthin,carotin and xanthophyll in addition to chloroplast.Gold brown algae-They include diatomin,a golden brown pigment.

Algae may be unicellular or multicellular.

FUNGI-Their size varies from 2u to few centimetres.

Types-Fungi are divided into 4 types.Yeasts-Yeast are tiny round ,unicellular fungi that live in colonies .they can survive in both aerobic and anearobic atmosphere.Mildews-They are also called unicellular fungi.most of them are parasites .they dont kill plants but makes them weak.Moulds-They are multicellular fungi.They consists of branching threads called mycelium.Moulds are aerobic.Mushrooms-These are the largest fungi.They mainly grow in humid conditions.

Protozoa-The size ranges from 2u to 200u.

Structure-amoeba is the most primitive .It has no definite shape.The outermost covering of cell wall that keeps on  in the form of pseduopodia .Paramecium is a slipper shaped animal it has tiny hair like structures called cilia on the outer membrane which help to swim in water.Euglena exhibits the characterstics of both plant and animals.it is animal like because it does not have cell wall  and has cell membrane but it is plant like because it can prepare its own food!.Trypansoma is a parasitic protozoan .it lives in the blood stream of human and cattle.

Viruses are acellular.When they are found in bacterial cells they are called bacteriophages.They consists of a central core of RNA or DNA surrounded by by a sheath of protien coat.Viruses range from 0.015 to 0.2 micron in size,they are ultra microscopic.Viruses may be rod shaped,polygonal,spherical or cubical.

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