Episode Guide

1. The Microbial Universe—The world of microorganisms is a dynamic one, and all other life forms depend on microbial metabolic activity. Recent genetic research has uncovered only about one percent of the microbes that remain to be discovered.

2. The Unity of Living Systems—All cellular organisms — prokaryotic and eukaryotic — share basic chemical similarities. Out of these similarities, however, emerge diverse patterns of cell assembly. Students encounter the tools to understand various cell types and their relationship to non-cell entities such as viruses.

3. Metabolism—The metabolic pathways that produce energy create important environmental transformations. Although living organisms have diverse ways of meeting their energy needs, there is an amazing similarity between all life forms as they carry out metabolism directed to the construction and use of necessary biological molecules.

4. Reading the Code of Life—DNA is central to cell activity, replicating with great fidelity and carrying the information for all proteins. Organisms also regulate the products made from genes in an effort to conserve energy and adapt to new environments.

5. Genetic Transfer—Microbial populations achieve genetic diversity through horizontal gene transfer. Bacteria may transfer genes from one to another by conjugation, transformation, or transduction. Scientists often exploit these processes through recombinant DNA.

6. Microbial Evolution—Recent genetic techniques have led to new theories of evolution and the relationships between organisms. Students examine this “evolution revolution,” using molecular sequences to trace the phylogenetic relationships of microbial life. Both the big picture of microbial evolution and the methods necessary for determining molecular phylogenies are examined.

7. Microbial Diversity—What is the relationship between the bacteria, archaea, and eukaryote branches of the tree of life, with their startling variety of organisms? Students see comparisons of organisms in their natural habitats and examine ways of studying these organisms in those habitats and in the laboratory.

8. Microbial Ecology—Humans and all life forms depend on microorganisms as the essential processors of oxygen, mineral nutrients for plant growth, and waste materials. Here we investigate some of the important environments dominated by microbes and how their presence is essential for human life.

9. Microbial Control—In certain situations, microbial control is a necessity. For instance, our food system requires sanitary conditions and hospitals require sterilization techniques. Here we see the options available for various levels of microbial control.

10. Microbial Interactions—There are many symbiotic relationships among microbes and between microbes and higher organisms. Microorganisms have developed mechanisms to defeat animals’ defenses against disease. Examples of beneficial and harmful symbiotic relationships are examined here.

11. Human Defenses—Both nonspecific and specific defense strategies can defeat the invasion of microbial pathogens. Students learn about the coordinated defense system of humans through visual analogy, animation, and examples of specific diseases.

12. Microbes and Human Diseases—How microbes come into contact with humans, and the many factors leading to disease outbreaks around the globe, are examined here. Students learn about current efforts to track infectious diseases and the considerations necessary to control disease worldwide.