Classification of microbes/ microorganisms
Microorganisms are clasdified on the basis of the cellular composition, size, nuclear structure as well as types of reproduction (Asexual or sexual)
1. Bacteria
2. Mycoplasma
3. Riekettsia
4. Chlamydia
5. Virus
6. Fungi
7. Algae
8. Yeast
9. Moulds
10. Protozoa
1. Bacteria
They are prokaryotes.
Generally unicellular
Grow attach to one another in cluster ( chain, rods, filaments)
They lack true nucleus
Divide by binary fission
With special staining methods their structural differences can seen.
Bacteria are parasitic when they live on or intake nourishment from animal host or living plant.
Some bacteria are harmless but some causes disease. For example, Pneumonia, Tuberculosis, Syphilis.
2. Mycoplasma
Small prokaryotic, without cell wall.
Enclosed in single plasma membrane
Multiply by binary fission
Their size is similar to virus but most properties resemble with bacteria.
Most of the them are commensals found in genitourinary tract of humans.
Three Mycoplasma species are human pathogen's-
1. Mycoplasma pneumoniae
2. Mycoplasma Hominis
3. Uroplasma urealyticum
3. Rickettsia
They are unicellular, intracellular parasites.
Transmitted by arthopod vectors except coxiella burnetti.
They appear as pleomorphic coccobacilli.
Able to grow and multiply only in cell culture, animals and thick embryo by binary fission.
Size is similar to virus but cell wall composition is similar to bacteria.
4. Chlamydia
Chlamydia are unicellular
Multiply by binary fission in host cell and their cell wall composition is similar to bacteria.
Chlamydia trachomatis, Chlamydia psittaci, Chlamydia Pneumonia.
5. Viruses
There are smallest of all microorganisms.
They have only RNA or DNA as genetic material but never both. They are non- cellular , no cytoplasm, not cell wall, not cell membrane.
Size ranges from 20nm-300nm, visualized only electron microscope.
Multiply only within living host cell.
Some virus enclosed by envelope of fat and protein molecules.
Viruses are-
Pox virus
Picorna virus
Hepatitis virus
Toga virus
Herpes virus
Retro virus
6. Fungi
They are non photosynthetic multicellular eukaryotic microorganisms.
Have rigid cells wall, cell wall is made up of Chitin.
They are saprophytic.
Most of species of fungi are non-motile.
Multiply by asexual and sexual.
Cause fungal infection
7. Yeast
Yeast are typically unicellular eukaryotic organism.
Multiply by binary fission.
Mainly occur on grapes, other fruits and plants.
Yeasts are also found in dung, oil, milk.
They are gram positive, they are responsible for fermentation.
Useful to man in making bread, cakes and wine.
Yeast cause disease.
Sporotrichosis
Mycoplamosis
Candidiasis
Blastomycisis
8. Algae
They are unicellular as well as multicellular green plants.
Require sunlight for growth, certain chlorophyll can prepare their food called autotrophs.
Multiply by binary fission and sexual reproduction.
They are larger than bacteria , protozoa and fungi.
Cannot ingest solid particle.
Some of algae cause disease or pathogenic.
Brown algae
Golden algae
Green algae
9. Moulds
Moulds are Multicellular eukaryotes.
Moulds live in soil
Penicillium is produced from a mould penicilium notatum used for treatment of infectious diseases.
Certain mould can cause disease - Mucormycosis (infection of lungs).
10. Protozoa-
Protozoa are unicellular, smallest eukaryotic animals.
Non-photosynthetic organism with protoplasm clearly differentiated into nucleus and cytoplasm.
Example, Amoeba; allows major changes in cell shape and pseudopodia help in movement of locomotion ingestion.
In cilliated protozoa preserve characteristic of cell.
Multiple by binary fission or multiple fission or sexual.
Many protozoa are parasite. For example malaria parasite.
Disease cause, amoebic dysentry, kala-azar, malaria, filaria etc.
0 Comments