Microbiology midterms

• Microbiology


  An advanced biology course that is the study of microbes, which are extremely small (microscopic) living organisms and certain non-living entities
• Living microbes (cellular microbes or microorganisms)

  • Bacteria
  • Archaea
  • Some algae
  • Protozoa
  • Some fungi
• Non-living microbes (acellular microbes or infectious particles)

  • Viroids
  • Prions
  • Viruses
• Microbes are ubiquitous (i.e., they are found virtually everywhere)
• Microorganisms


  • They are ubiquitous organisms that are too small to be seen by the unaided eye
  • They represent the major fraction of the Earth's biomass
  • Plants and animals are engaged in the world of microbes, their evolution and survival are influenced by microbial activities

  
• Germs


  The microbes that cause disease
• Pathogens


  The scientific term for disease-causing microbes
• Non-pathogens


  Microbes that do not cause disease; the vast majority of microbes are non-pathogens

  
• Indigenous microbiota


  Microbes that live on and in our bodies

  
• Opportunistic pathogens


  Microbes that can cause disease, but usually do not; they can be thought of as microbes that are awaiting the opportunity to cause disease
• Categories of diseases caused by pathogens

  • Infectious diseases
  • Microbial intoxications
• Microbial cells first appeared

  Between 3.8 and 4.3 billion years ago

  
• For the first 2 billion years of Earth's existence, microorganisms are capable to survive without oxygen in the atmosphere
• Candidates for the first microorganisms on Earth

  • Archaea
  • Cyanobacteria

  
• Phototrophic microorganisms (organisms that harvest energy from sunlight) occurred


  1 billion years ago
• First phototrophs


  • Purple sulfur bacteria
  • Green sulfur bacteria
• Cyanobacteria (oxygenic phototrophs) evolved and began the slow process of oxygenating Earth's atmosphere, multicellular life forms eventually evolved

  
• Infectious diseases of humans and animals have existed for as long as humans and animals have inhabited the planet
• Sumerians and Egyptians produced many foods using fermentation, such as bread, wine, and beer


  Around 5,000 B.C.E.
• They did not have the knowledge to explain exactly how those products were made, nor why fermentation happened. Therefore, they commonly viewed fermentation as a miracle provided by their gods
• During The Dark Ages in Medieval Europe, the pandemic plague has killed as much as one-third of the continent's population in individual pandemics in the Middle Ages
• Plague


  A zoonotic disease from domestic and wild rats, caused by Yersinia pestis
• Robert Hooke


  Illustrated the first known image of microscope and fruiting molds, and started to formulate the "Cell Theory"
• Theodore Schwann and Matthias Jakob Schleiden


  Proposed the Cell Theory in 1838, which states that all plants and animals are made up of cells

  
• Microbiology

  An advanced biology course that is the study of microbes, which are extremely small (microscopic) living organisms and certain non-living entities
• Living microbes (cellular microbes or microorganisms)

  • Bacteria
  • Archaea
  • Some algae
  • Protozoa
  • Some fungi
• Non-living microbes (acellular microbes or infectious particles)

  • Viroids
  • Prions
  • Viruses
• Microbes are ubiquitous (i.e., they are found virtually everywhere)
• Germs


  The microbes that cause disease
• Pathogens

  The scientific term for disease-causing microbes
• Non-pathogens

  Microbes that do not cause disease; the vast majority of microbes are non-pathogens
• Indigenous microbiota


  Microbes that live on and in our bodies
• Opportunistic pathogens


  Microbes that can cause disease, but usually do not; they can be thought of as microbes that are awaiting the opportunity to cause disease
• Categories of diseases caused by pathogens

  • Infectious diseases
  • Microbial intoxications
• Microbial cells first appeared

  Between 3.8 and 4.3 billion years ago

  
• For the first 2 billion years of Earth's existence, microorganisms are capable to survive without oxygen in the atmosphere
• Candidates for the first microorganisms on Earth

  • Archaea
  • Cyanobacteria
• Phototrophic microorganisms (organisms that harvest energy from sunlight) occurred


  1 billion years ago
• First phototrophs


  • Purple sulfur bacteria
  • Green sulfur bacteria
• Cyanobacteria (oxygenic phototrophs) evolved and began the slow process of oxygenating Earth's atmosphere, multicellular life forms eventually evolved