biology- microbiology

• What are the main characteristics used for the classification of cells?


  Size of cell, type of cell, presence of organelles
• What is a micrometre?


  10$^{-6} m$ or 10$^{-3} \mu m$
• What is a nanometre?


  10$^{-9} m$ or 10$^{-6} mm$ or 10$^{-3} \mu m$
• What is the typical length of bacteria?


  1. 2 μm
• What shape do bacteria typically have?


  Bacteria are usually roughly cylindrical, but can also be rods or spirals
• Why are bacteria classified as prokaryotes?


  Because they do not have membrane-bound organelles
• What type of organisms are fungi?


  Microscopic eukaryotes
• What is the size range of yeast cells?


  1. 12 μm
• What distinguishes eukaryotes from prokaryotes?


  Eukaryotes have chromosomes contained within a nucleus and membrane-bound organelles
• How are multicellular fungi structured?


  They are composed of microscopic threads or hyphae that grow over or through their food source
• What is a parasite?


  An organism that lives on or in another organism at the expense of that organism
• What are examples of multicellular parasites?


  Parasitic plants and flatworms
• What are microscopic parasites?


  Single-celled eukaryotic organisms
• What is the size range of microscopic parasites?


  1. 10 μm
• What are the components of a virus?

  Genetic material (DNA or RNA) surrounded by a protein coat
• What is unique about the structure of viruses?


  Viruses are acellular and do not contain organelles
• What is the typical size range of most viruses?


  20-30 nm
• Why do we need microscopes to study microorganisms?


  Microorganisms cannot be seen by the naked eye
• What is the principle behind light and electron microscopes?


  Both use lenses to magnify the image
• How do electron microscopes differ from light microscopes?

  Electron microscopes use a beam of electrons, while light microscopes use glass lenses
• What is magnification?


  How much bigger the image is than the actual object
• What is resolution in microscopy?


  The ability to distinguish between two adjacent points
• How does resolution affect image clarity?


  A high resolution microscope can show a clearer image
• How does the resolution of a camera phone relate to microscopy?


  An old phone will probably have a low resolution compared to a modern phone
• What are the advantages and disadvantages of light microscopes?


  Advantages:

  • Inexpensive
  • Easy to use

  
  

  Disadvantages:

  • Must be used with care to avoid damage
  • Limited to examining living microorganisms that are not too small
• What are the limitations of electron microscopes?


  • Cannot use living material
  • Operate in a vacuum