NEET BIOLOGY

Detailed explanation-1: -Mitochondria and chloroplasts likely evolved from engulfed prokaryotes that once lived as independent organisms. At some point, a eukaryotic cell engulfed an aerobic prokaryote, which then formed an endosymbiotic relationship with the host eukaryote, gradually developing into a mitochondrion.

Detailed explanation-2: -Mitochondria originated by permanent enslavement of purple non-sulphur bacteria. These endosymbionts became organelles through the origin of complex protein-import machinery and insertion into their inner membranes of protein carriers for extracting energy for the host.

Detailed explanation-3: -There are two major organelles in eukaryotic organisms that have resulted from endosymbiosis, mitochondria (common to most eukaryotes) and chloroplasts (found in plants and algae only), as well as a few less obvious examples.

Detailed explanation-4: -Mitochondria arose through a fateful endosymbiosis more than 1.45 billion years ago.

Detailed explanation-5: -Explanation: The Endosymbiotic Theory states that the mitochondria and chloroplast in eukaryotic cells were once aerobic bacteria (prokaryote) that were ingested by a large anaerobic bacteria (prokaryote).