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Microbiology: Key Concepts and History

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  • What are microorganisms?

    Microorganisms are organisms too small to be seen with the unaided eye, including bacteria, fungi, protozoa, microscopic algae, viruses, and prions.

  • Name three roles of microbes in the environment.

    Microbes decompose organic waste, incorporate nitrogen gas into organic compounds, and generate oxygen by photosynthesis.

  • What is the microbiome?

    The microbiome is the group of microbes that live stably on or in the human body, helping maintain health and preventing pathogenic growth.

  • Define normal microbiota and transient microbiota.

    Normal microbiota are microbes permanently colonizing the body; transient microbiota colonize temporarily.

  • Who established the system of scientific nomenclature and what does it involve?

    Carolus Linnaeus established scientific nomenclature, using two names: genus (capitalized) and specific epithet (lowercase), both italicized or underlined.

  • What are the three domains of microorganisms?

    The three domains are Bacteria, Archaea, and Eukarya.

  • List key characteristics of bacteria.

    Bacteria are unicellular prokaryotes with peptidoglycan cell walls, reproduce by binary fission, and may have flagella for movement.

  • How do archaea differ from bacteria?

    Archaea are prokaryotes lacking peptidoglycan in their cell walls, often live in extreme environments, and are not known to cause human disease.

  • What distinguishes fungi from other microorganisms?

    Fungi are eukaryotes with chitin cell walls; yeasts are unicellular, molds are multicellular with hyphae.

  • Describe protozoa characteristics.

    Protozoa are eukaryotes that absorb or ingest organic chemicals, may be motile, and reproduce sexually or asexually.

  • What are viruses and how do they replicate?

    Viruses are acellular, consist of DNA or RNA core with a protein coat, and replicate only inside living host cells.

  • What is spontaneous generation versus biogenesis?

    Spontaneous generation is the idea life arises from nonliving matter; biogenesis states living cells arise only from preexisting living cells.

  • Who disproved spontaneous generation and how?

    Louis Pasteur disproved spontaneous generation using S-shaped flasks that allowed air but trapped microbes, showing microbes come from the environment.

  • What is fermentation and who demonstrated its microbial basis?

    Fermentation is microbial conversion of sugar to alcohol without air, demonstrated by Louis Pasteur.

  • Define pasteurization.

    Pasteurization is heating a liquid briefly to kill harmful bacteria without evaporating alcohol, developed by Pasteur.

  • What are Koch's postulates?

    Experimental steps to prove a specific microbe causes a specific disease, developed by Robert Koch.

  • What is vaccination and who pioneered it?

    Vaccination is inoculation to produce immunity, pioneered by Edward Jenner using cowpox to protect against smallpox.

  • What is chemotherapy in microbiology?

    Chemotherapy is treatment of disease with chemicals, including synthetic drugs and antibiotics.

  • Who discovered the first antibiotic and what was it?

    Alexander Fleming discovered penicillin, the first antibiotic, produced by Penicillium fungus.

  • What is microbial resistance?

    Microbial resistance is the ability of microbes to withstand antimicrobial drugs, complicating treatment.

  • What is the focus of molecular genetics in microbiology?

    Molecular genetics studies how microbes inherit traits and how genetic information is carried in DNA molecules.

  • What is recombinant DNA technology?

    Recombinant DNA is DNA made from two different sources, enabling microbes to produce proteins like human hormones.

  • Name four beneficial activities of microorganisms.

    Microbes recycle vital elements, treat sewage, clean pollutants (bioremediation), and control insect pests.

  • What are biofilms?

    Biofilms are complex microbial communities attached to surfaces, which can be beneficial or harmful.

  • Define emerging infectious diseases (EIDs).

    EIDs are new or increasing diseases caused by pathogens, influenced by factors like antibiotic resistance and human activity.

  • Give examples of recent emerging infectious diseases.

    Examples include COVID-19, Monkeypox, Zika virus, H1N1 influenza, Ebola, and antibiotic-resistant infections like MRSA.