Chapter 1 Bio 205

Chapter 1 The Microbial World and You

List several ways in which microbes affect our lives.

Several ways are: Sourdough bread, Used in the synthesis of such chemical products as acetone, organic acids, enzymes, alcohols, and many drugs. Humans and many other animals depend on the microbes in their intestines for digestion and the synthesis of some vitamins that their bodies require. Marine and freshwater microorganisms form the basis of the food chain in ocean, lakes, and rivers. Soil microbes help break down wastes and incorporate nitrogen gas from the air into organic compounds.

2. Recognize the system of scientific nomenclature that uses genus and specific epithet names.

Scientific Nomenclature: assigns each organism two names — the genus is the first name and is always capitalized; the specific epithet (species name) follows and is not capitalized. The organism is referred to by both the genus and the specific epithet, and both names are underlined or italicized. By custom, after a scientific name has been mentioned once, it can be abbreviated with the initial of the genus followed by the specific epithet. Scientific names can, among other things, describe an organism, honor a researcher, or identify the habitat of a species. For example, consider Staphylococcus aureus, a bacterium commonly found on human skin. Staphylo- describes the clustered arrangement of the cells; coccus indicates that they are shaped like spheres. The Specific epithet, aureus, is Latin for golden, the color of many colonies of this bacterium.

3. Differentiate among the major characteristics of each group of microorganisms.

Bacteria: relatively simple, single-celled (unicellular) organisms. Because their genetic material is not enclosed in a special nuclear membrane, bacterial cells are called prokaryotes. Individual bacteria may form pairs, chains, clusters, or other groupings. Bacteria are enclosed in cell walls that are largely composed of a carbohydrate and...