# DBT JRF 2020 — Question 5

Exam: DBT JRF 2020 · Section: A · Topic: Cell Biology · Difficulty: Easy

## Question

Which of the following is NOT true?

## Options

- **A.** prokaryotes are unicellular organisms
- **B.** eukaryotic cells are evolutionarily more ancient than prokaryotic cells
- **C.** prokaryotic cells lack nucleus whereas eukaryotic cells have a nucleus
- **D.** eukaryotes can be either multicellular or unicellular organisms

## Answer

Option B

## Explanation

Prokaryotes (Bacteria and Archaea) appeared approximately 3.5 billion years ago, while eukaryotes evolved much later (~1.5–2 billion years ago). The endosymbiotic theory proposes that mitochondria and chloroplasts arose from prokaryotic ancestors engulfed by a proto-eukaryotic cell. Therefore, saying 'eukaryotic cells are evolutionarily more ancient than prokaryotic cells' is FALSE. All other statements — prokaryotes are unicellular, prokaryotes lack a membrane-bound nucleus, and eukaryotes can be unicellular (e.g., yeast, Amoeba) or multicellular — are TRUE.

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