MICRO-ORGANISM

INDEX -

INTRO OF MICRO-ORGANISMS BACTERIA

Use of bacteria Harmful bacteria Reproduction in bacteria virus Reproduction in virus FUNGI Use of fungi Harmful fungi REPRODUCTION IN FUNGI

Micro-organism

Microbes are all around us . They are in the air we breathe in the soil and in the untreated water . Microorganisms play an important role in our lives Some of these are very useful but some are very harmful . As decomposer of organic material , they help to keep the soil fertile . And recycle once living matter into valuable nutrients.

Microorganism are very small we

BACTERIA

Anton van leeuwenhoek [1676] discovered the bacteria in pond water and tartar scrapped from teeth and called them as animalcules. Much has been added to our knowledge about bacteria during last few decades. They have following important characters-

They are prokaryotic. The flagella whenever present are

made up of single strand.

Basically, they are unicellular

Cell wall is made up of peptidoglycan.

They are smallest of all the living organism with a cellular organisation.

Cytoplasmic streaming and sapvacuoles are absent in bacterial cell. In some bacteria gas vacuoles may be present.

Mostly bacteria are heterotrophic due to absence of chlorophyll

Useful bacteria

They help in fertility of soil.

They help in digestion.

They help in decomposition of dead remains.

They help in nitrogen fixation.

They help in nitrification.

They help in ammonification.

They help in making medicines.

They help in making of curd.

Harmful Bacteria- They pollute water.

They spoil food.

They cause harmful diseases like Typhoid, Tetanus, Pertussis, Cholera, Diphtheria and Tuberculosis etc.

They do Denitrification.

They do botulism.

Reproduction in bacteria Binary fission- It is the common method

of reproduction and take place under favourable conditions.

Nuclear body start dividing into two nuclear bodies.

This take place after replication of nuclear body and splitting of two nuclear bodies is helped by mesosome.

Now the new cell wall are join together from middle.

Virus- Virus are smallest living thing in

world. Name virus means Venom or Poisonous. Study of virus is called virology. Virus and Bacteriophage are much smaller then the Bacteria. They are made up of one of nucleic acid DNA or rna [never both] and protein. Genetic material are enclosed with a protective layer of protein. When they are in host cell they are living and when they outside the host cell they are non-living. Virus are not as complex as cell, if for no other

Harmful virus They do common cold.

Common cold virus also effect the throat.

Virus do harmful disease like as aids.

They also cause disease to plants

Fungi They are heterotrophic due to

absence of chlorophyll.

They become either parasites and saprophytes.

Thallus is made up of colourlessfilamentous structure called hyphae.

Cell wall is made up of fungus cellulose.

The nuclei are eukaryotic in nature

Study of fungi is called mycology.

Useful Fungi They are help in fermentation.

It helps in making of bread.

They help in making of medicines.

They are edible

They are saprophytic in nature so they are good decomposer.

They respire but without oxygen

Harmful Fungi They spoils food.

They pollute water.

They cause diseases to plants

They cause diseases to human being.

They cause more harmful disease than bacteria.

Disease called athlete foot is also a fungal disease.

Reproduction in fungi They reproduce by all three

method- Vegetative Asexual Sexual In vegetative it reproduce by six

method are fragmentation,budding, fission, oidia, chlamydospores,

gemmae. In asexual it reproduce by two method are spore formation, conidia formation. And in sexual it reproduce by isogamy,