Science Microorganisms

• Unicellar are one celled organisms which are mostly invisible to a naked eye.
• multicellar are more than 2 celled organisms
• Desease causing microorganisms are called pathogens
• Bacteria are simple, unicellar organisms
• some species are free living (saptrotrophs)
• The cell envelope encloses the contents of the cell. it consists of three layers
• Appendages:

  The flagella that are distributed over the surface of bacterial cells for movement and attactment
• Such distribution can be kbserved when bacteria are subjected to a Gram staining process
• A bacterial colony is a group of the same kind of bacteria growing together on a specific culture medium placed on a petri dish
• In terms of shape, bateria fall into three morphological categories:

  cocci

  bacilli

  spirilla
• Cocci (singular: coccus)
• Diplococci (in pairs)
• terads (consisting of four cells)
• sarcina (consisting 8 cells)
• streptococci (in chains)
• staphylococci (in clusters like a bunch of grapes)
• baccilli are rod-shaped oor cigar shaped bacteria
• Spirilla are curved or twisted or spiral shaped bacteria with fairly ridged bodies
• A single bacterium can become two in 20 minutes
• Three types of axesual reproduction:

  binary fission

  budding

  spore formation
• The sexual method is considered a rare phenomenon that can happen in some special circumtances.
• The sexual method is through genetic recombination
• Some species of bacteria uses leather tanning. Tanning is a process that converts the skin of ananimal into leather.
• protozoans or "animal like" protist are desease causing or pathogenic.
• Entamoeba hisolytica a species of amoeba, is parasitic and can cause amoebic dysentery. The parasite lives in the intestine of humans and feeds on intestinal walls, causing bleeding ulcers.
• Plasmodium falciparum causes malaria
• trypanosoma gambiense is a protozoan species that can cause sleeping sickness. The parasite is spread to humans and other domestic animals by the bite of an infected tsetese fly.
• trichonoympha is another flagellated protozoan that lives in symbiosis int he digestive tract of termites.
• plasmodium is the protozoan that causes malarial fever in humans.
• The plant like protist commomly known as algae
• phytoplankton known as the dinoflagelletes
• excessive increase in the population growth of dinoflagelletes is a phenomenon called algal bloom, popularly know as red tide
• Red tides produce toxins that kill much of the coastal wildlife and can cause paralysis and other illness or even death to humans.
• Fungi exist in almost every terrestrial and aquatic habitat.
• 3 layers of cell envelope:

  Capsule

  Cell wall

  plasma membrane