Chapter 16

Explain how each of the following characteristics contributes to the success of prokaryotes: cell wall, capsule, flagella, fimbriae, endospores.

A new organism has been discovered. Tests have revealed that it is unicellular, is autotrophic, and has a cell wall that contains peptidoglycan. Based on this evidence, it should be classified as a(n) a. alga. b. archaean. c. protist. d. bacterium.

Which pair of protists has support structures composed of silica? a. dinoflagellates and diatoms b. diatoms and radiolarians c. radiolarians and forams d. forams and amoebozoans

Which of the following prokaryotes is not pathogenic? a. \(Chlamudia\) b. \(Rhizobium\) c. \(Streptococcus\) d. \(Salmonella\)

Explain why prokaryote populations can adapt rapidly to changes in their environment.

\(Chlamydomonas\) is a unicellular green alga. How does it differ from a photosynthetic bacterium, which is also single-celled? How does it differ from a protozoan, such as an amoeba? How does it differ from larger green algae, such as sea lettuce (\(Ulva\))?

The bacteria that cause tetanus can be killed only by prolonged heating at temperatures considerably above boiling. This suggests that tetanus bacteria a. have cell walls containing peptidoglycan. b. secrete endotoxins. c. are autotrophic. d. produce endospores.

The bacteria that cause tetanus can be killed only by prolonged heating at temperatures considerably above boiling. This suggests that tetanus bacteria a. have cell walls containing peptidoglycan. b. secrete endotoxins. c. are autotrophic. d. produce endospores.

In a process known as "coral bleaching," high water temperatures cause corals to expel the dinoflagellates that normally reside within their cells. How might coral bleaching affect coral reefs?

Probiotics, foods and supplements that contain living microorganisms, are thought to cure problems of the digestive tract by restoring the natural balance of its microbial community. Sales of these products total billions of dollars a year. Explore the topic of probiotics and evaluate the scientific evidence for their beneficial effects. A good starting point is the website of the U.S. Food and Drug Administration, which regulates advertising claims of health benefits of dietary supplements. U.S. Food and Drug Administration website, www.fda.gov/food/ dietary- supplements.

Imagine you are on a team designing a moon base that will be self-contained and self-sustaining. Once supplied with building materials, equipment, and organisms from Earth, the base will be expected to function indefinitely. One of the team members has suggested that everything sent to the base be sterilized so that no bacteria of any kind are present. Do you think this is a good idea? Predict some of the consequences of eliminating all bacteria from an environment.

The buildup of \(\mathrm{CO}_{2}\) in the atmosphere resulting from the burning of fossil fuels is regarded as a major contributor to global warming (see Module 7.14). Diatoms and other microscopic algae in the oceans counter this buildup by using large quantities of atmospheric \(\mathrm{CO}_{2}\) in photosynthesis, which requires small quantities of iron. Experts suspect that a shortage of iron may limit algal growth in the oceans. Some scientists have suggested that one way to reduce \(\mathrm{CO}_{2}\) buildup might be to fertilize the oceans with iron. The iron would stimulate algal growth and thus the removal of more \(\mathrm{CO}_{2}\) from the air. A single supertanker of iron dust, spread over a wide enough area, might reduce the atmospheric \(\mathrm{CO}_{2}\) level significantly. Do you think this approach would be worth a try? Why or why not?