Endosymbiosis

In News

• An organism that has been around from 2 billion years ago has given biologists from Centre for Cellular and Molecular Biology, Hyderabad (CCMB), a clue as to how mitochondria became an inseparable part of animal and plant cells.

Primary and Secondary Endosymbiosis

• A symbiotic relationship where one organism lives inside the other is known as endosymbiosis.
• Primary endosymbiosis refers to the original internalization of prokaryotes by an ancestral eukaryotic cell, resulting in the formation of the mitochondria and chloroplasts.
  • Two membranes surround mitochondria and chloroplasts.
  • The inner one is derived from the bacterial ancestor and the outer “mitochondrial” or “chloroplast” membrane is actually derived from the host-cell membrane.
• Secondary endosymbiosis: Several groups of algae therefore have chloroplasts acquired at second-hand by what is termed secondary endosymbiosis.

Mitochondria

• Mitochondria are well known to be integral parts of the eukaryotic cell.
• They are dubbed the power houses of the cell, because they help in generating energy in the form of ATP within the cell, powering it.
• But they were not always part of the animal and plant cells. Once, about two billion years ago, a prokaryotic organism (without a nucleus) called archaea captured a bacterial cell.

Source: TH