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GATE 2025 BT – Question 21

General Biology · Microbiology: History, bacterial classification and diversity, cell wall, Gram positive and negative bacteria, archaea, methods · 1 mark · Multiple select

Which of the following features is/are used to distinguish Archaea from Bacteria?

  1. Gram-staining
  2. Peptidoglycan in the cell wall
  3. Presence of N-acetylglucosamine
  4. 16S rRNA sequences

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Correct answer: (B) Peptidoglycan in the cell wall; (D) 16S rRNA sequences

Explanation

Bacterial cell walls contain peptidoglycan, which archaea lack (some have pseudomurein), and the 16S rRNA sequences of the two domains are different, which is how Woese separated them. Gram staining is used within both groups and N-acetylglucosamine is a general sugar found in both.