What are the characteristics of microorganisms?

Microorganisms are tiny living organisms that cannot be seen with the naked eye. They are present everywhere—in air, water, soil, and even inside living beings. Despite their diversity, microorganisms share certain common features that distinguish them from larger organisms.

1. Microscopic in Size

The most important characteristic is that microorganisms are so small they can only be seen under a microscope. They range from a few micrometers (bacteria) to nanometers (viruses).

2. Simple Structure

Most microorganisms have a very simple body design compared to plants and animals.

• Bacteria are prokaryotic, meaning they lack a true nucleus.
• Fungi, protozoa, and algae are eukaryotic, having a well-defined nucleus.
• Viruses are acellular (not truly living outside a host).

3. Rapid Reproduction

Microorganisms reproduce very quickly under favorable conditions. For example, bacteria can multiply within minutes, which explains why food spoils fast in warm and moist environments.

4. Diverse Habitats

They can survive in extreme conditions where other organisms cannot. Some live in hot springs, salty lakes, polar ice, and even inside the human body.

5. Variety in Nutrition

Microorganisms show different modes of nutrition. Some, like algae, prepare their own food through photosynthesis. Others, like fungi and bacteria, depend on dead or living organisms for nutrition.

6. Useful and Harmful Roles

Microorganisms are unique because they can be both beneficial and harmful. They help in food production, medicine, and agriculture, but they can also cause diseases and spoil food.