AP BIOLOGY

Detailed explanation-1: -The theory of how mitochondria, chloroplasts and other membrane-bound organelles in eukaryotic cell likely arose from a symbiosis between aerobic prokaryotes and host anaerobic eukaryotic ancestors. Developed by Lynn Margulis.

Detailed explanation-2: -The leading hypothesis, called the endosymbiotic theory, is that eukaryotes arose as a result of a fusion of Archaean cells with bacteria, where an ancient Archaean engulfed (but did not eat) an ancient, aerobic bacterial cell.

Detailed explanation-3: -The endosymbiotic theory describes how a large host cell and ingested bacteria could easily become dependent on one another for survival, resulting in a permanent relationship. Over millions of years of evolution, mitochondria and chloroplasts have become more specialized and today they cannot live outside the cell.

Detailed explanation-4: -The endosymbiotic theory states that some of the organelles in eukaryotic cells were once prokaryotic microbes. Mitochondria and chloroplasts are the same size as prokaryotic cells and divide by binary fission. Mitochondria and chloroplasts have their own DNA which is circular, not linear.

Detailed explanation-5: -The endosymbiotic theory posits that some eukaryotic cell organelles, such as mitochondria and plastids, evolved from free-living prokaryotes. Available data indicate that the mitochondrial endosymbiosis initiated the evolution of the eukaryotic cell, as suggested by Margulis.