Download Endosymbiotic Theory

The Origin of the Mitochondrion
and the Chloroplast
Endosymbiotic Theory
 We know that eukaryotic plant cells contain both of
these organelles, each of which performs an important
function
Mitochondria - ATP energy
production by cellular respiration
Chloroplast –
photosynthesis
Where did mitochondria and chloroplasts come from?
The answer is: Endosymbiotic theory
Endo symbiotic Theory
1. It is based on the premise that chloroplasts and mitochondria were early
prokaryotic cells
2. It is proposed that a larger cell “engulfed “ these smaller prokaryotic cells
3. The larger cell was able to make its own food through photosynthesis and break
down food (produce energy) by cellular respiration
Endosymbiotic Theory
There are the following evidences of the theory:
Both mitochondria and chloroplasts have:
1. single circular DNA that is different from that of the cell
nucleus and that is similar to that of bacteria
2. double membranes
3. ribosomes - are like those found in bacteria
4. New mitochondria and plastids are formed only through a
process similar to binary fission.
5. If a cell's mitochondria or chloroplasts are removed, cell does
not have the means to create new ones.