Explain how the membrane-enclosed organelles of eukaryotic cells arose

Answer 1

The origin of membrane-enclosed organelles in eukaryotic cells is believed to have arisen through a process known as endosymbiosis. This theory suggests that eukaryotic cells engulfed prokaryotic cells through a process of phagocytosis, forming a symbiotic relationship in which the prokaryotic cells eventually evolved into organelles within the eukaryotic cell.

One of the most well-known examples of this process is the origin of mitochondria, which are thought to have evolved from aerobic bacteria that were engulfed by a primitive eukaryotic cell. Over time, the engulfed bacteria developed a symbiotic relationship with the host cell, providing energy in the form of ATP through aerobic respiration. Similarly, chloroplasts in plant cells are believed to have originated from photosynthetic cyanobacteria that were engulfed by ancestral eukaryotic cells.

Through this process of endosymbiosis, eukaryotic cells acquired membrane-enclosed organelles that allowed them to perform specialized functions such as energy production and photosynthesis. This evolutionary event is thought to have played a key role in the development of complex multicellular organisms with diverse cellular functions.