Microorganisms

Overview

Microorganisms (or microbes) are living things too small to be seen with the naked eye. They include bacteria, viruses, fungi, protozoa, and algae. This topic forms a core part of the Science section in UPTET Paper II and connects biology with everyday life, health, agriculture, and the environment.

For UPTET, you must know the classification of microorganisms, their basic structure, and most importantly, their useful and harmful roles. Questions often test whether you can distinguish between types of microbes, recall examples of diseases caused by each, and identify beneficial applications like fermentation, nitrogen fixation, and antibiotic production. A clear understanding of this topic also supports pedagogy questions on how to teach life sciences through real-world examples.

Master the characteristics that separate bacteria from viruses from fungi, memorise key disease-microbe pairs, and understand the economic importance of microbes in food, medicine, and agriculture.

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Key Concepts

• **Microorganisms are classified into five major groups:** bacteria, viruses, fungi, protozoa, and algae. Of these, viruses are unique because they show living characteristics only inside a host cell.

• **Bacteria are single-celled prokaryotes** (no true nucleus). They can be spherical (cocci), rod-shaped (bacilli), or spiral (spirilla). Some are autotrophic; most are heterotrophic.