1.1 MEMBERS OF THE MICROBIAL WORLD

 MEMBERS OF THE MICROBIAL WORLD 

• Microbiology is defined as the study of organisms and agents are too small to be seen clearly by unaided eye i.e; the study of microorganisms. 
• Less than about one millimeter in diameter cannot be seen clearly and must be examined with a microscope.
• Some microorganisms, particularly eucaryotic microbes, are visible without microscopes.For example, bread molds and filamentous algae are studied by microbiologists, yet are visible to naked eye, as two bacterias  Thiomargarita and Epulopiscium.

IMPORTANT CHARACTERISTICS OF MICROORGANISMS.

• Large and multicellular relatively simple in their construction, lacking highly differentiated cells and distinct tissues.
• Microbiologists, first isolated a specific microorganism from a population
  and then culture it. 
  
• Microbiology employs techniques—such as sterilization and the use of culture media that are necessary for successful isolation and growth of microorganisms. 
• Microorganisms are diverse, and their classification has always been a challenge for microbial taxonomists. 
• Some microbes are motile like animals, but also have cell walls and are photosynthetic like plants.  Such microbes cannot be placed easily into one kingdom or another. 
  
• Important factor in classifying microorganisms is that some are composed of prokaryotic cells and others of eukaryotic cells. 
• Prokaryotic cells  have a much simpler morphology than eukaryotic cells and lack a true membrane-delimited nucleus. [organisms with a primordial nucleus].
• In contrast, eukaryotic cells  have a membrane-enclosed nucleus; they are more complex morphologically and are usually larger than prokaryotes.
• Development of a classification scheme that divided organisms into five kingdoms: the Monera, Protista, Fungi, Animalia, and Plantae.
• Microorganisms (except for viruses, which are acellular and have their own classification system) were placed in the first three kingdoms.

continued............