Microorganisms: Bacteria, Viruses, Fungi, Protozoa and Algae and the Useful Microbes Exams Ask

The Unseen World That Runs Ours

Microorganisms are living things too small to see without a microscope. Anton van Leeuwenhoek first saw them in the 1670s using hand-made lenses. They live in soil, water, air, our gut and even boiling springs.

Five groups matter for exams: bacteria, viruses, fungi, protozoa and algae. Most microbes are harmless and many are useful; only a small fraction cause disease, and those are called pathogens.

Louis Pasteur showed that microbes cause fermentation and disease, which overthrew the old idea of spontaneous generation. Robert Koch linked specific bacteria to specific diseases, such as the tubercle bacillus to tuberculosis.

Exam questions on this topic are really matching questions: this microbe does this job or causes this disease. This short builds that match table group by group.

1. Which microorganism converts milk into curd?

2. Who discovered penicillin from the mould Penicillium?

3. Which of the following is NOT a bacterial disease?

4. The cholera-causing bacterium Vibrio cholerae has which shape?

5. Which microbe fixes atmospheric nitrogen in the root nodules of leguminous plants?

6. Antibiotics are ineffective against which of the following?

7. Blue-green algae (cyanobacteria) such as Nostoc and Anabaena are classified as:

8. A teacher sets curd by adding a spoon of curd to lukewarm milk and keeping it warm overnight. Why must the milk be kept warm?