Chapter 1-4

• Prokaryotes


  Bacteria and Archaea, size(1um)
• Eukaryotes


  Algae, Fungi, Protozoa (up to 5mm)
• Viruses


  Acellular microbes, smallest in size (20nm)
• Key figures in biology

  • Robert Hooke: Beginning of cell theory
  • Van Leeuwenhoek: First microscope
  • Pasteur: Swan neck, aseptic technique, fermentation and pasteurization
  • Lister: Antiseptics
  • Koch: Anthrax
  • Jenner: Smallpox
  • Fleming: Penicillin
  • Linnaeus: Naming system
• Swan neck experiment


  1. Broth sterilized, air escapes but microbes can't get in

  2. Flask tilted, microbes get in, broth is contaminated
• Atom


  Smallest unit of matter
• Element


  One type of atom (e.g. Na, O, N, F)
• Molecule


  2 or more of the same atoms (e.g. Na2, O2)
• Compound


  2 or more different atoms (e.g. NaO2)
• Atoms form bonds to fill their outermost shells and become stable
• Electron shell configuration


  • 1st shell = 2
  • 2nd shell = 8
  • 3rd shell = 8
• Ionic bond


  Attraction between ions of opposite charges
• Covalent bond


  Atoms share pairs of electrons
• Hydrogen bond


  Formed by N, O, F atoms
• Carbohydrates


  Ready source of energy for cells, 3 types: mono saccharides, di saccharides, poly saccharides
• Lipids


  Include fats, complex lipids and steroids, energy storage for cells
• Fats


  Glycerol backbone and 1 or more fatty acids
• Types of fats


  • Monoacylglycerides: one fatty acid
  • Diacylglycerides: two fatty acids
  • Triacylglycerides: three fatty acids
• Saturated fatty acids


  No double bonds (e.g. butter)
• Unsaturated fatty acids


  Double bonds (e.g. vegetable oil)
• Proteins


  Made up of amino acids, most act as enzymes
• Amino acids


  Joined by covalent peptide bonds
• mRNA nucleotides


  Adenine, Uracil, Guanine, Cytosine
• DNA nucleotides


  Adenine, Thymine, Guanine, Cytosine
• Light microscope


  Uses 2 lenses to magnify 10-100 times
• Electron microscope


  Uses electrons to magnify up to 500,000 times, allows viewing of viruses and internal cell structures
• Simple staining procedure


  Put sample on slide, heat, add stain, wash, dry, view
• Bacteria have a net negative charge
• Positive stain


  Binds to bacteria and colors them, while background is clear
• Negative stain


  Colors outer surface while bacteria remain clear
• Gram stain


  Differentiates bacteria based on cell wall structure (thick or thin)
• Capsule stain


  Detects thick layer of polysaccharide outside the cell
• Acid-fast stain


  Detects presence of waxy fatty acid in cell wall
• Spore stain


  Stains internal structure of bacteria
• Flagella stain


  Stains external structure of bacteria
• Prokaryotes


  DNA is arranged as one circular chromosome, lack membrane-enclosed organelles
• Eukaryotes


  DNA is found in nucleus, have membrane-enclosed organelles
• Bacterial shapes

  • Coccus - spherical
  • Bacillus - rod-shaped
  • Vibrio - curved
  • Spirillum - spiral
  • Spirochete - corkscrew
• Bacterial flagella arrangements


  • Monotrichous - single
  • Lophotrichous - two or more
  • Amphitrichous - on opposite sides
  • Peritrichous - all over the cell
• Fimbriae


  Allow cell to adhere to surfaces, contribute to pathogenicity