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🔬 Biology  ·  Biological Classification  ·  NEET

Organisms whose cells lack a true, membrane-bound nucleus are called:

Answer: prokaryotes.

  • A prokaryotes
  • B eukaryotes
  • C fungi
  • D green plants

Correct answer: A. prokaryotes

Explanation: Prokaryotes (like bacteria) have no membrane-bound nucleus.

Whittaker's Five KingdomsMoneraprokaryotesProtistaunicell. eukaryotesFungichitin wallPlantaecellulose wallAnimaliano wallNOT in any kingdom: Viruses (non-cellular), Viroids (RNA, no coat), Lichens (alga+fungus symbiosis)Classification criteria: cell structure, nutrition mode, body organisation, reproduction, phylogeny

Whittaker's five-kingdom system (1969) groups all cellular life by cell structure and nutrition; viruses, viroids, and lichens fall outside this system entirely since they aren't independently classifiable as one of the five.

Concept context

Whittaker's five kingdom system covering Monera, Protista, Fungi, plus viruses, viroids, and lichens. A foundational NEET chapter on how living organisms are grouped.

Read the full Biological Classification notes →