Smallest living organism in the world

The smallest known living organism in the world is Mycoplasma genitalium, a type of bacterium. This tiny organism has a cell diameter of about 200 to 300 nanometers (0.2–0.3 micrometers), making it smaller than many viruses and visible only with an electron microscope. Mycoplasma genitalium is a parasitic bacterium that lives in human and animal cells, often found in the human urinary and genital tracts.

Characteristics of Mycoplasma genitalium:

• Genome Size: It has one of the smallest genomes of any self-replicating organism, with around 580,000 base pairs, which is minimal for sustaining life.
• Minimal Cellular Machinery: Unlike other bacteria, M. genitalium lacks a cell wall, making it more flexible and enabling it to survive in various environments within host organisms.
• Research Significance: Due to its minimal genome, M. genitalium is often studied to understand the basic genetic requirements for life.

Other candidates for “smallest organism” include ultra-small bacteria and certain types of archaea, but Mycoplasma genitalium remains the smallest self-replicating, free-living organism known.