A microorganism is a tiny living organism that is usually too small to be seen with the naked eye. They include a wide variety of organisms such as bacteria, fungi, viruses, protozoa, and algae. Microorganisms can be found everywhere: in the air, soil, water, and even inside our bodies. They play important roles in processes like digestion, decomposition, and the nitrogen cycle.

Some microorganisms are helpful, like those that aid in digestion or produce medicines (such as antibiotics), while others can cause diseases.

Types of Microorganisms:

Bacteria: Single-celled organisms that can be found everywhere. While some bacteria cause diseases (e.g., Salmonella), others are beneficial and essential for processes like digestion and nitrogen fixation in plants.
Fungi: These include yeasts and molds. Some fungi cause diseases (like athlete's foot), but others are used in food production (e.g., yeast in bread-making) or medicine (e.g., antibiotics like penicillin).
Viruses: These are much smaller than bacteria and can only reproduce inside a host cell. Viruses cause diseases like the flu, COVID-19, and the common cold.
Protozoa: Single-celled organisms that can live in water or soil. Some are harmless, but others can cause diseases like malaria or amoebic dysentery.
Algae: Photosynthetic microorganisms found in water. While many algae are harmless, some types, like blue-green algae, can produce harmful toxins.

Role of Microorganisms:

Decomposition: Microorganisms break down dead organic material, recycling nutrients back into the ecosystem.
Food Production: Microorganisms are used in the production of various foods and beverages, such as yogurt, cheese, beer, and bread.
Medicine: Certain microorganisms produce antibiotics, which are used to treat bacterial infections. Some microorganisms are also used in the production of vaccines.
Environmental Processes: Microorganisms play a key role in the nitrogen cycle, which is essential for plant growth, and they help break down pollutants in the environment.