endosümbiootilised

endosümbiootilised refers to a biological process where one organism lives inside another organism in a symbiotic relationship. This type of symbiosis, known as endosymbiosis, can occur between various types of life forms, including bacteria, archaea, and eukaryotes. The key characteristic is that the endosymbiont resides within the host cell or tissue.

A prominent example of endosymbiosis is the origin of eukaryotic organelles like mitochondria and chloroplasts. According to the endosymbiotic theory, these organelles were once free-living prokaryotes that were engulfed by an ancestral host cell. Instead of being digested, they established a mutually beneficial relationship with the host. The engulfed prokaryote provided energy or other resources, while the host offered protection and nutrients. Over evolutionary time, these endosymbionts became integrated into the host cell, losing many of their independent functions and becoming essential components of eukaryotic life. Evidence supporting this theory includes the presence of their own DNA, ribosomes, and double membranes within mitochondria and chloroplasts, which resemble those of bacteria. This phenomenon has profoundly shaped the diversity and complexity of life on Earth.