Which microorganism is typically classified as a eukaryote?

RRB Nsg. Superintendent-2026 (Shift -3rd)

Applied Microbiology & Infection control

Easy

Appeared in: RRB Nsg. Superintendent-2026 (Shift -3rd)

Explanation

Protozoa are single-celled organisms classified under the Kingdom Protista.
They are defined as eukaryotes because their cells contain a true, membrane-bound nucleus that houses their genetic material.
Additionally, their cytoplasm contains various membrane-bound organelles, such as mitochondria and the Golgi apparatus, which perform specialized functions.

Option B: Bacteria are the classic example of prokaryotes. Their cells are simpler, lacking a true nucleus and any membrane-bound organelles.
Option C: Cyanobacteria, also known as blue-green algae, are a phylum of bacteria. As bacteria, they are prokaryotes, not eukaryotes.
Option D: Viruses are acellular, meaning they are not cells. They are infectious particles consisting of genetic material (DNA or RNA) surrounded by a protein coat. Since they are not cells, they cannot be classified as either prokaryotes or eukaryotes.

Visual 1: Diagram: A side-by-side comparison of a prokaryotic cell and a eukaryotic cell, highlighting the presence of a nucleus and organelles in the eukaryote and the lack thereof in the prokaryote.
Visual 2: Infographic: A chart showing the classification of microorganisms, with branches for Eukaryotes (Protozoa, Fungi), Prokaryotes (Bacteria, Archaea), and Acellular (Viruses, Prions).

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Cellular classification of microorganisms (Eukaryote vs. Prokaryote) as background academic context rather than a clinical decision trigger.
Understanding the difference between prokaryotes and eukaryotes is fundamental to antimicrobial therapy in nursing.
Antibiotics (antibacterial drugs) are designed to target structures unique to prokaryotic cells, such as the peptidoglycan cell wall or 70S ribosomes. This allows the drugs to kill bacteria without harming the patient's eukaryotic cells.
Antifungal and antiprotozoal drugs are more challenging to develop because they must target eukaryotic pathogens without causing significant toxicity to the patient's own eukaryotic cells.

How to Approach the Question

First, identify the key term in the question: 'eukaryote'.
Recall the definition of a eukaryote: an organism whose cells contain a membrane-bound nucleus and other specialized organelles.
Evaluate each option against this definition.
Consider 'Protozoa'. These are known to be complex single-celled organisms, which fits the description of a eukaryote.
Consider 'Bacteria' and 'Cyanobacterium'. These are classic examples of prokaryotes, which lack a nucleus.
Consider 'Viruses'. Recall that viruses are not cells at all; they are acellular particles and thus cannot be eukaryotes.

Concept Tested & Keywords

Concept Tested: Cellular classification of microorganisms (Eukaryote vs. Prokaryote)
Stem keywords: microorganism, classified, eukaryote
Lead-in keywords: Which

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