Human Diseases | Famous Books for UPSC Exam (Summary & Tests) PDF Download

Bacteria: The Versatile Prokaryotes

Bacteria, minuscule single-celled organisms classified as prokaryotes, exhibit remarkable adaptability in various environments, ranging from soil to the human bowel and even the ocean. These microorganisms can be differentiated based on their shape, cell wall characteristics, and genetic variations. The process of binary fission fuels their rapid multiplication.

Viruses: Intriguing Infectious Agents

Viruses, characterized by their tiny size and unique mode of replication, can only duplicate inside living cells of other organisms. These entities display diversity, infecting animals, plants, and microorganisms, but can only be transmitted by biological vectors. Viruses consist of a DNA or RNA genome encased within a protein shell called the capsid, some of which may possess an additional internal or external membrane covering. Interestingly, they lack enzymes necessary for energy production.

Protozoa: Diverse Unicellular Eukaryotes

Protozoa, a diverse group of unicellular eukaryotic organisms, primarily feed on bacteria and other food sources. Diseases caused by protozoa can be severe and life-threatening.