Critical Thinking Questions
30. Describe briefly how you would detect the presence of a non-culturable prokaryote in an environmental sample.
31. Why do scientists believe that the first organisms on Earth were extremophiles?
32. A new bacterial species is discovered and classified as an endolith, an extremophile that lives inside rock. If the bacteria were discovered in the permafrost of Antarctica, describe two extremophile features the bacteria must possess.
33. Mention three differences between bacteria and archaea.
34. Explain the statement that both types, bacteria and archaea, have the same basic structures, but built from different chemical components.
35. A scientist isolates a new species of prokaryote. They note that the specimen is a bacillus with a lipid bilayer and cell wall that stains positive for peptidoglycan. Its circular chromosome replicates from a single origin of replication. Is the specimen most likely an Archaea, a Gram-positive bacterium, or a Gram-negative bacterium? How do you know?
36. Think about the conditions (temperature, light, pressure, and organic and inorganic materials) that you may find in a deep-sea hydrothermal vent. What type of prokaryotes, in terms of their metabolic needs (autotrophs, phototrophs, chemotrophs, etc.), would you expect to find there?
37. Farmers continually rotate the crops grown in different fields to maintain nutrients in the soil. How would planting soybeans in a field the year after the field was used to grow carrots help maintain nitrogen in the soil?
38. Imagine a region of soil became contaminated, killing bacteria that decompose dead plants and animals. How would this effect the carbon cycle in the area? Be specific in stating where carbon would accumulate in the cycle.
39. Explain the reason why the imprudent and excessive use of antibiotics has resulted in a major global problem.
40. Researchers have discovered that washing spinach with water several times does not prevent foodborne diseases due to E. coli. How can you explain this fact?
41. Your friend believes that prokaryotes are always detrimental and pathogenic. How would you explain to them that they are wrong?
42. Many people use antimicrobial soap to kill bacteria on their hands. However, overuse may actually increase the risk of infection. How could this occur?
