[Campbell Biology P.633] Which of the following statements correctly differentiates between ... | Practice Question

Which of the following statements correctly differentiates between the bacterial groups described in the text?

  • A: Spirochetes are distinguished by their external flagella, while Proteobacteria are exclusively heterotrophic.
  • B: Cyanobacteria are the only prokaryotes capable of oxygen-generating photosynthesis, and some Gram-positive bacteria are sources of antibiotics.
  • C: Chlamydias possess typical gram-negative cell walls, but Gram-positive bacteria entirely lack peptidoglycan.
  • D: *Thiomargarita namibiensis* is a photoautotroph producing sulfur as a waste product, whereas *Treponema pallidum* is a free-living spirochete.

Explanation

The text states that 'These gram-negative photoautotrophs are the only prokaryotes with plantlike, oxygen-generating photosynthesis' referring to Cyanobacteria. It also mentions that 'Soil-dwelling species in the genus Streptomyces are cultured as a source of antibiotics', and Streptomyces is a Gram-positive bacterium, making option B correct.