mod 6

• Domains of Living Organisms

  • Eukarya
  • Bacteria
  • Archaea
• Eukarya


  Contains all members of the living world except for the prokaryotes, breed among themselves
• Microorganisms in Eukarya


  • Fungi
  • Protozoans
  • Algae
  • Helminths
• Fungi


  Unicellular or multicellular eukaryotes, non photosynthetic, include unicellular yeasts, multicellular molds, and fleshy fungi (mushrooms)
• Protozoans


  Unicellular eukaryotes, nonphotosynthetic
• Algae


  Multicellular eukaryotes, photosynthetic, most important photosynthesizing organisms on Earth, include brown algae, green algae, red algae, golden brown, and dinoflagellates
• Helminths


  Multicellular eukaryotes, most complex in terms of morphology
• Bacteria


  Unicellular prokaryotes, composed of peptidoglycan, use wide range of substances for nutrition
• Archaea


  Have the same basic shape, size, and appearance of bacteria but have biochemical differences, lack of peptidoglycan, tend to inhabit extreme environments
• Viruses


  Lack many characteristics of living cells, including the ability to replicate without the assistance of host cell biosynthetic processes, acellular, can only be seen with an electron microscope, consist of nucleic acid surrounded by a protein coat, smaller than bacteria
• Prions


  Proteinaceous in nature and yet infectious, infectious agents consisting of proteins but no nucleic acid, often associated with diseases such as "bovine spongiform encephalopathy" or "mad cow disease", "scrapie" in sheep and other neurologic diseases in humans
• Principal Differences Between Prokaryotic & Eukaryotic Cells

  • Size of cell
  • Nucleus
  • Membrane Organelles
  • DNA (Chromosomes)
  • Ribosomes
  • Cell wall
  • Plasma Membrane
  • Cell Division
  • Sexual recombination
  • Cytoplasm
  • Flagella
  • Glycocalyx
• Cell Division


  • Virus Replication
  • Fungi Budding
  • Eukaryotic cell may ingest a Prokaryotic Cell through Phagocytosis
  • Eukaryotic cell may ingest a Virus through Pinocytosis
• Prokaryotic Cell Structure (Bacteria)

  • Glycocalyx
  • Flagella
  • Cytoplasmic Membrane
  • Cytoplasm
  • Endospore
  • Pili
  • Cell Wall
• Glycocalyx


  Viscous, gelatinous layer composed of polysaccharide/polypeptide, includes slime layer and capsule, functions to prevent phagocytosis, aid adherence, protect against classification, inhibit nutrients from moving out, act as a barrier
• Flagella


  Organ of locomotion (motility), run & tumble movement, chemotaxis, flagellin protein, includes atrichous, monotrichous, lophotrichous, amphitrichous, peritrichous, and axial filament/endoflagella/periplasmic flagella
• Cytoplasmic Membrane


  Maintains cell integrity, regulates transport, specialized functions like respiration, photosynthesis, protein secretion
• Cytoplasm


  Viscous aqueous suspension of protein, nucleic acid, dissolved organic compounds, mineral salts, contains enzymes and storage granules
• Endospore


  Specialized resting cells, highly durable and resistant to extreme conditions, formed through sporulation/sporogenesis, germinate to become vegetative cells
• Pili


  Proteinaceous, hair-like appendages, shorter and thinner than flagella, for bacterial conjugation, includes common pili/attachment pili/fimbriae and sex pili/conjugated pili/F pili
• Cell Wall


  Outer covering of most bacterial, fungal, algal, and plant cells, gives shape and resistance to lysis, consists of peptidoglycan, includes gram positive and gram negative cell walls
• Staining Methods


  • Gram Staining
  • Acid-fast Staining
  • Negative Staining
  • Endospore Staining
  • Flagella Staining
• Gram Staining


  Classifies bacteria into two large groups: gram positive and gram negative
• Acid-fast Staining


  Used to distinguish Mycobacterium species and some Nocardia species
• Negative Staining


  Used to demonstrate the presence of capsules
• Endospore Staining


  Used to detect the presence of endospores
• Flagella Staining


  Used to demonstrate the presence of flagella
• Bacterial Antigens


  • Flagella = H antigen
  • Capsule = O antigen
  • Cell wall = V antigen
  • Fimbriae = X antigen
• History of Microbiology


  • Robert Hooke
  • Anton van Leeuwenhoek
  • Francisco Redi
  • John Needham
  • Lazzaro Spallanzani
  • Rudolf Virchow
  • Louis Pasteur
  • Ignaz Semmelweis
  • Joseph Lister
• Robert Hooke


  Observed a thin slice of cork under a microscope and coined the term "cell", beginning of cell theory
• Anton van Leeuwenhoek


  First to observe microorganisms (animalcules), father of microbiology
• Francisco Redi


  Opposed spontaneous generation, showed that life could not arise from non-life/pre-existing cells
• John Needham


  Strengthened theory of spontaneous generation, heated broth and observed microbial growth
• Lazzaro Spallanzani


  Opposed spontaneous generation, sealed flask with broth, heated, and observed no growth of microorganisms
• Rudolf Virchow


  Challenged spontaneous generation, proposed theory of biogenesis that life could only arise from pre-existing living cells
• Louis Pasteur


  Disproved spontaneous generation, discovered fermentation and connection between microorganisms and food spoilage, introduced pasteurization and vaccines, father of immunology, started golden age of microbiology
• Ignaz Semmelweis


  Observed that doctors who did not disinfect hands transferred infections from patient to another, introduced the importance of handwashing and chlorinated lime
• Joseph Lister


  Introduced the concepts of aseptic techniques, methods and procedures employed to prevent contamination, used carbolic acid
• Lazzaro Spallanzani


  • Opposed Spontaneous Generation
  • Sealed flask with broth, heated, no growth of microorganisms
• Rudolf Virchow


  • Challenged Spontaneous Generation
  • Theory of Biogenesis: "Life could only arise from pre-existing living cells"