13.6–13.10: In humans, bacteria can have harmful or beneficial health effects

Bacterial effects on human health vary widely. Many are beneficial and many are neutral, while some can be harmful.

Question 13.15

A population of Escherichia coli can double every ________ in an ideal laboratory culture.

  • a) 20 seconds
  • b) 2 minutes
  • c) 2 days
  • d) 20 minutes
  • e) 2 hours

Question 13.16

Plasmids containing genes for antibiotic resistance can be exchanged between bacterial cells in a culture by:

  • a) conjugation.
  • b) artificial exchange.
  • c) cloning.
  • d) transduction.
  • e) conduction.

Question 13.17

Which group of organisms utilizes the largest variety of energy sources?

  • a) prokaryotes
  • b) fungi
  • c) protists
  • d) invertebrate animals
  • e) vertebrate animals

Question 13.18

Which of the following statements about antibiotics is incorrect?

  • a) Penicillin was the first antibiotic widely used to fight bacterial infections.
  • b) Antibiotics help microbes compete with other microbes.
  • c) Antibiotic-resistant microbes are selected for in humans who are taking antibiotics.
  • d) Antibiotics, though effective against viruses, are not effective against bacteria.
  • e) Antibiotics are used not just in human health care but also in agriculture.

Question 13.19

Which of the following domains are the most closely related, in that they share a unique common ancestor?

  • a) archaea and bacteria
  • b) archaea and eukarya
  • c) bacteria and eukarya
  • d) None of the above; all three domains evolved from different ancestors.
  • e) None of the above; all three domains are equally related to one another.

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