Diversity of Microorganisms

• Biodiversity


  The wide variety of plants, animals & microorganisms on Earth
• Microorganisms


  Organisms that are too small to be seen by the naked eye
• Classification of organisms


  • Prokaryotes
  • Eukaryotes
• Prokaryotes


  • Unicellular
  • Small cells
  • Does not have true nucleus - DNA is free in cytoplasm
  • Contains no membrane bound organelles - no mitochondria/plasmids
  • DNA is circular - plasmid
  • Cell wall present
• Eukaryotes


  • Mostly multicellular
  • Larger cells
  • DNA is contained in the nucleus
  • Contains membrane bound organelles
  • DNA is linear
  • Cell wall only sometimes present
• Kingdoms


  • Monera
  • Protista
  • Fungi
  • Plantae
  • Animalia

  
• Viruses


  Not part of a Kingdom - do not display all 7 characteristics of life

  
• Characteristics of life


  • Movement
  • Respiration
  • Sensitivity
  • Growth
  • Reproduction
  • Excretion
  • Nutrition
• Viruses are not seen as true cells

  
• Viruses

  Can reproduce but only within specific host cells (Genetic parasites)

  
• Glycocalyx


  A slime capsule that protects bacteria from drying out
• Glycocalyx


  • Serves protective, adhesive and receptor functions
• Cell wall


  A semi-rigid casing containing peptidoglycan
• Cell wall


  • Provides structural support and shape for the cell
• Cell membrane


  A thin membrane made up of lipids and proteins that surrounds the cytoplasm
• Cell membrane


  • Controls the flow of material into and out of the cell
• Ribosomes


  Particles composed of protein and RNA
• Ribosomes


  • Site of protein synthesis
• Nucleoid


  Contains Bacteria's genetic material/DNA
• Nucleoid


  • Contains no nuclear membrane – not seen as a true nucleus
• Plasmids


  A small circular DNA molecule
• Plasmids


  • Genes carried in plasmids provide bacteria with genetic advantages
• Pili


  Fine, hairlike bristles
• Pili


  • Helps with adhesion to other cells and surfaces
• Conjugation pilus


  An elongate hollow appendage used to transfer DNA to other cells during cell adhesion
• Flagella


  A specialized whipe-like appendage
• Flagella


  • Rotating filament allows cell to be pushed forward, providing motility (Movement)
• Characteristics of bacteria


  • Smallest cells – still bigger than viruses
  • Unicellular – Only made up of one cell
  • Bacteria distinguished by their shape
• Characteristics of bacteria


  • Prokaryotes
  • Heterotrophs – need organic carbon host decaying or alive
  • Many heterotrophs can also photosynthesize (autotrophic)
  • Range from aerobic to anaerobic
  • Ubiquitous – found in a wide variety of habitats
• Endospore formation


  1. Form under unfavourable conditions

  2. Hard resistant structure

  3. Contains some cytoplasm and DNA

  4. Can survive for a prolonged time in unfavourable conditions

  5. Endospores remain dormant until environmental conditions favour bacterial growth and reproduction
• Asexual reproduction - Binary fission

  1. Bacteria duplicates its genetic material

  2. Divides into two parts with each part receiving one copy of DNA

  
• Asexual reproduction - Budding


  A cell is developed from a small part of the parent cells' body
• Conjugation


  1. The transfer of genetic material between bacterial cells by direct cell to cell contact

  2. Takes place through pillus

  3. Allows bacteria to transfer beneficial adaptations

  
• Fungi


  • Can be unicellular or multicellular
  • Eukaryotic
  • Heterotrophic

  
• Types of fungi


  • Saprotrophic - live off dead organic matter
  • Parasitic - live off living organisms
• Stolon/horizontal hyphae


  Also known as
• Hyphae


  • Feathery filaments mainly responsible for vegetative growth in Fungi
  • Cell walls are made of chitin
• Aerial hyphae


  A type of hyphae bearing the sporangium
• Sporangium


  An enclosed capsule that contains spores

  
• Spore


  A reproductive cell capable of developing into a new individual