Chapter 3

Concepts and Tools for Studying Microorganisms

Chapter Summary and Essay Questions

As an introduction to the microorganisms, Chapter 3 surveys some basic concepts that apply to all microorganisms. The first section discusses three ways in which bacterial and archael cells are not that much different than their eukaryotic relatives. First, all cells need to maintain homeostasis. Second, many microbes are found organized into communities, called biofilms, in which cells communicate with each other and which have some characteristics of multicellular organisms. Third, compartmentalizationin prokaryotic cells occurs, allowingthe cells to carry out metabolic reactions and organismal functionsthat are very similar to those of eukaryotic organisms. In the second section, systems used to classify organisms are introduced.The final section of the chapter reviews various types of microscopes used for investigating microorganisms. After you have studied Chapter 3, you should be able to answer the following essay questions:

  1. Identify the five emerging properties of living organisms.
  2. Assess the importance of homeostasis in cells and organisms.
  3. Explain how unicellular microbial cells form multicellular interactions through the development of a biofilm.
  4. Debate the statement that prokaryotes are “simple organisms.”
  5. Distinguish between the organizational patterns seen in all cells.
  6. Identify and explain the role of eukaryotic organelles.
  7. Compare eukaryotic organelles with prokaryotic microcompartments.
  8. Define taxonomy and describe the contributions made by Linnaeus, Haeckel, Whittaker, and Woese.
  9. Explain why the three-domain system was devised, and identify the domains to which microorganisms belong.
  10. Describe the binomial system of nomenclature and show how microbial names are written.
  11. Outline the various levels in the taxonomic classification scheme and show how they are organized.
  12. Identify the book that contains the characteristics of bacterial species, and list several traditional criteria for bacterial classification.
  13. Assess how molecular taxonomy has affected bacterial classification.
  14. Define the units of measurement used for microorganisms, and rank the microorganisms from largest to smallest in size.
  15. Outline the basic operation of the light microscope, including the concept of resolving power and the use of the oil immersion objective.
  16. Explain the need for contrast when observing microorganisms and describe the two major stain techniques that can be used to increase contrast.
  17. Compare the operation and function of dark-field, phase-contrast, and fluorescence microscopy.
  18. Identify the operational basis and use for the transmission and scanning electron microscopes.