Microbes and Diseases

Overview

Microbes and Diseases is a core topic in the Science portion of MAHA TET Paper II, testing your understanding of the microscopic world and its impact on human health. This topic bridges biology with everyday life, making it highly relevant for upper-primary teaching. Questions typically focus on identifying types of microorganisms, matching diseases with their causative agents, understanding modes of transmission, and knowing basic prevention methods.

For the exam, you must be able to distinguish between bacteria, viruses, fungi, and protozoa—their basic structures, sizes, and the diseases they cause. The topic also connects to the Environmental Studies and Health and Hygiene sections, so understanding it well gives you an advantage across multiple areas. Expect 2–4 direct questions, often in match-the-following or assertion-reason format.

Mastery requires memorizing key disease-microbe pairs, understanding transmission routes (air, water, contact, vectors), and knowing prevention strategies including vaccination and hygiene practices.

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Key Concepts

• **Microorganisms (Microbes)**: Living organisms too small to be seen with the naked eye; include bacteria, viruses, fungi, protozoa, and algae. Not all microbes are harmful—many are beneficial (e.g., gut bacteria, yeast in bread-making).

• **Bacteria**: Single-celled prokaryotes (no true nucleus); can be rod-shaped (bacilli), spherical (cocci), or spiral (spirilla). Reproduce by binary fission. Some cause disease; others are useful in curd formation, nitrogen fixation, and decomposition.

• **Viruses**: Non-cellular entities; consist of genetic material (DNA or RNA) surrounded by a protein coat. Cannot reproduce on their own—need a living host cell. Smallest of all microbes. Cause diseases like common cold, influenza, dengue, and COVID-19.

• **Fungi**: Eukaryotic organisms (have true nucleus); include yeasts (unicellular) and moulds/mushrooms (multicellular). Reproduce by spores. Cause diseases like ringworm and athlete's foot; useful in making bread, antibiotics (penicillin).

• **Protozoa**: Single-celled eukaryotes; often live in water or as parasites. Cause diseases like malaria (Plasmodium), amoebic dysentery (Entamoeba), and sleeping sickness.

• **Communicable Diseases**: Diseases that spread from one person to another through air, water, food, direct contact, or vectors (insects/animals). Also called infectious or contagious diseases.

• **Vectors**: Living organisms that transmit pathogens from one host to another. Examples: mosquitoes (malaria, dengue), houseflies (cholera, typhoid), rats (plague).