MIC 205 Exam 1 questions with correct answers

Describe some of the destructive and beneficial actions of microbes. CORRECT ANSWER Marine and freshwater microorganisms form the basis of the food chain in oceans, lakes, and rivers. Soil microbes break down wastes and incorporate nitrogen gas from the air into organic compounds, thereby recycling chemical elements among soil, water, living organisms, and air. What percentage of all cells in the human body are bacterial cells? CORRECT ANSWER An adult human is composed of about 30 trillion body cells and harbors another 40 trillion bacterial cells. Microbes that live stably in and on the human body are called the human microbiome, or microbiota. Humans and many other animals depend on these microbes to maintain good health. Distinguish a genus from a specific epithet. CORRECT ANSWER Genus (plural: genera) 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. Example: 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. Which groups of microbes are prokaryotes? Which are eukaryotes? CORRECT ANSWER Prokaryotes: Bacteria, Archaea, Eukaryotes: Fungi, protozoa, algae, animal parasites'. Viruses: very different from the other microbial groups mentioned here. They are acellular (that is, they are not cells), and most are so small that they can be seen only with an electron microscope. What are the three domains? CORRECT ANSWER -Ba