MBIO 1010 Lecture 1

• What Is Microbiology?

  The study of organisms too small to be seen with the naked eye

  -Bacteria, viruses, single celled eukaryotes

  Some microorganisms are visible to the naked eye:

  - Fungi, algae

  Some microbes are multicellular:

  -Myxobacteria, slime molds
• Why Is Microbiology Important?

  -Microbes are the oldest form of life

  -Largest mass of living material on Earth

  -Carry out major processes for biogeochemical cycles

  -Can live in places unsuitable for other organisms

  -Other life forms require microbes to survive.
• Bumps on roots of plants are called nodules that have microbes able to do nitrogen fixation taking atm nitrogen gas and convert it to ammonium that help them grow

   
• Structures and Activities of microbial cells - All cells have the following in common

  cytoplasmic membrane

  cytoplasm

  ribosomes

  genetic material

  genome

  chromosomes

  plasmid
• Structural categorization of microbes: Eukaryotes

  Membrane bound nucleus

  Membrane bound organelles

  Complex internal structure

  Division by mitosis and meiosis
• Major groups of Eukaryotic microbes

  Protists and Fungi
• Protists(eukaryotic microbes)

  Unicellular or multicellular without differentiation into tissues

  • Protozoa - animal-like microorganisms
  • Algae - photosynthetic plant-life microorganisms
  • Slime molds and water molds - filamentous
• Fungi (eukaryotic microbes)

  • Yeasts - unicellular
  • Molds - filamentous
  • Mushrooms - multicellular
• Structural categorization of microbes: Prokaryotes

  No membrane bound nucleus or organelles

  generally smaller

  Simple internal structure

  Divide by binary fission

  Most are unicellular
• Major groups of Prokaryotic microbes

  Bacteria

  Archaea
• Bacteria (prokaryotic microbes)

  Genetically diverse

  Extremely diverse metabolic styles

  Includes both pathogens and non-pathogens
• Archaea (prokaryotic microbes)

  Genetically and biochemically distinct from bacteria

  Also have diverse metabolism

  Never pathogenic (As of yet)

  Most famous for living in extreme environments
• viruses

  Acellular infectious particles

  Extremely small

  Obligate intracellular parasites

  Lack independent metabolism

  • No ribosomes
  • No ribosomal RNA
  • Cannot be classified with other microbes
• cytoplasmic membrane

  • defining feature
  • if you don't have this, you don't have a cell
  • Barrier that separates the inside of the cell from the outside environment
• Cytoplasm

  Aqueous mixture of macromolecules, ions, and proteins
• Ribosomes

  • lots of them because we need lots of proteins
  • Site of protein synthesis
• Genetic material

  • All cells store their genetic information as DNA
  • The information is divided into functional units called genes
• Genome

  • A cell's full complement of genes
  • Chromosome + plasmid
• Chromosome

  • essential to cellular function
  • take them away, cell will die
  • A genetic element carrying genes essential to cellular function
• Plasmid

  • typically circular
  • take them away, cell will survive
  • can contain antibiotic resistance mechanisms
  • useful to make a bacteria do what you want it to do
  • A piece of DNA that carries non-essential genes (ex. Genes for antibiotic resistance, genes for nitrogen fixation, etc)
• microbiology is defined by techniques

  • culture media for isolation and growth of organisms in pure cultures
  • biochemical to study cell components
  • molecular and genetic techniques