Yeast is?

Appeared in: SGPGI Nursing Officer-2022

Explanation

Yeast is classified as a fungus.
As described in microbiology, fungi can exist as either molds (filamentous) or yeasts (unicellular).
Yeasts are eukaryotic organisms, meaning their cells contain a true nucleus and other membrane-bound organelles.
A key feature is their cell wall, which is composed of chitin, distinguishing them from bacteria (peptidoglycan cell wall) and animal cells (no cell wall).

Option A: Viruses are not cells; they are acellular infectious agents that consist of genetic material (DNA or RNA) inside a protein coat. They are obligate intracellular parasites, meaning they cannot replicate without a host cell.
Option C: Bacteria are prokaryotic organisms. Their cells lack a nucleus and other membrane-bound organelles. Their cell walls are made of peptidoglycan, not chitin.
Option D: Animals are multicellular, eukaryotic organisms. While their cells are eukaryotic like yeast, they are organized into complex tissues and organs, and critically, they lack a cell wall.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Classification of microorganisms as background academic context rather than a clinical decision trigger.
Understanding the classification of yeast is crucial because it dictates the type of treatment. Fungal infections (mycoses), like those caused by Candida albicans, require antifungal agents, not antibiotics.
Antifungal drugs often target structures unique to fungi, such as the ergosterol in the cell membrane or the chitin in the cell wall, minimizing harm to human cells.
Nurses must educate patients that antibiotics can sometimes increase the risk of a yeast infection by killing off beneficial bacteria that normally keep yeast populations in check.

How to Approach the Question

Identify the key term in the question: 'Yeast'.
This is a factual recall question that tests basic knowledge of biological classification.
Recall the major categories of microorganisms: viruses, bacteria, fungi, and protozoa.
Consider the defining characteristics of yeast. It is a single-celled organism with a nucleus.
Evaluate the options based on this knowledge: Viruses are acellular. Bacteria are prokaryotic (no nucleus). Animals are multicellular. Fungi are eukaryotes that can be unicellular (yeasts) or multicellular (molds).
Conclude that yeast fits the description of a fungus.

Concept Tested & Keywords

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E6 Medicine Davidson Principles Practice 24e p. 121-123

Practise the full SGPGI Nursing Officer-2022

Attempt every question from this paper in a timed mock, then review the full solution for each one.