Since the symbiotic hypothesis states that mitochondria and also chloroplasts developed from bacteria entering a eukaryotic bio cell to type a symbiotic relationship, similarities in between bacteria and these semiautonomous oribel show solid evidence that this hypothesis is correct.

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Mitochondria share very similar characteristics through purple-aerobic bacteria. Lock both usage oxygen in the manufacturing of ATP, and they both perform this by utilizing the Kreb’s Cycle and also oxidative phosphorylation. (mitochondria top top the left and purple aerobic bacteria ~ above the right)


Chloroplasts are very comparable to photosynthetic bacteria in that they both have actually very comparable chlorophyll the harness light power to convert into chemistry energy. (Chloroplast on the left and also photosynthetic bacteria ~ above the right)


Although over there are countless similarities in between mitochondria and also purple aerobic bacteria and also chloroplasts and photosynthetic bacteria, they show up to be slight and also to have developed via evolution.


Size of mitochondria and also chloroplasts in comparison come bacteria is another basic observation that supports the endosymbiotic hypothesis. Mitochondria, chloroplasts, and prokaryotes (bacteria) range from around one to ten microns in size. (1 micron=1X10-6 Meters) This seems very basic, but if there was a huge difference in sizes between these 3 components, the hypothesis would show up to be false.

DNA, RNA, Ribosomes and Protein Synthesis

The an initial piece of proof that essential to be discovered to assistance the endosymbiotic theory was even if it is or no mitochondria and also chloroplasts have actually their very own DNA and also if this DNA is similar to bacterial DNA. This was later on proven to be true because that DNA, RNA, ribosomes, chlorophyll (for chloroplasts), and protein synthesis. This detailed the very first substantial proof for the endosymbiotic hypothesis. That was likewise determined that mitochondria and also chloroplasts divide independently of the cabinet they live in.

Mitochondria having their own DNA and dividing individually of the cabinet is what ultimately results in just mitochondrial DNA gift inherited through one’s mother because only one egg cell has DNA when a sperm cabinet does not. (This relationship also further proves that the discovered qualities of mitochondria room true.)


This level that independence among semiautonomous organelles shows that they room not really related come the cell core or other organelles that a eukaryotic bio cell. Because they are not related, it shows up to it is in even an ext probable the mitochondria and also chloroplasts were initially bacteria that gotten in the eukaryotic cell via endocytosis to type a symbiotic relationship.

Evolutionary Drive

Scientists (particularly Lynn Margulis) then began to think that if mitochondria and also chloroplasts were truly bacteria the were taken into eukaryotic cells via endocytosis, climate there should be a historical drive to encourage this symbiotic relationship. About 3.8 billion year ago, there were just anaerobic bacteria in existence since Earth’s environment did no contain any kind of oxygen. The first photosynthetic bacteria arose around 3.2 billion years back and began producing big quantities the oxygen as a byproduct the photosynthesis. Oxygen is very toxic to cells, and also as a result, this anaerobic, photosynthetic bacteria came to be less effective at enduring in their environment. At this point, some of the anaerobic bacteria developed into aerobic bacteria. Aerobic bacteria space much better suited to this oxygen comprise environment and also they also use oxygen in the process of make ATP (a molecule the stores a good amount that easily available energy). One necessary factor the both of these bacteria lacked to be the capability to ingest big quantities of nutrient from the surrounding environment via phagocytosis. Around 1.5 billion year ago, the an initial nucleated cabinet (the eukaryote) was developed through evolution, and also this cell had actually the groundbreaking ability to take it in huge quantities of nutrients via phagocytosis. The fact that bacteria, which are very similar to mitochondria and also chloroplasts, existed prior to the eukaryotic bio cell shows evidence that it was bacteria the was integrated into a eukaryotic bio cell rather than standard scale being totally separate in evolutionary history. This timeline likewise gives evidence as to why a symbiotic partnership would be beneficial.


The photosynthetic and also aerobic bacteria were normally driven to get in into this relationship due to the fact that the eukaryotic cell supplies both protection and nutrients, and also the bacteria supply methods for standard scale to harness more energy than they previously can using only glycolysis.


This (above) is the second stage that the glycolysis process (the only stage that in reality produces the ATP), and as you have the right to see it only produces a complete of 4 ATP (2 net ATP). Once this process is an unified with the Krebs cycle and oxidative phosphorylation (which calls for mitochondria), the network amount of ATP produced is 36-38 molecules.

By eukaryotic cells engulfing photosynthesis bacteria, they can then produce glucose molecules that might then be offered to go through the catabolic processes in the mitochondria, and hence, the eukaryotic cell harnesses even an ext energy 보다 it would certainly on its own. Having actually so much energy to drive cellular procedures makes this new eukaryotic cell more fit because that survival.

Double Phospholipid Bilayer

A fairly simple piece of proof for the endosymbiotic hypothesis is the truth that both mitochondria and also chloroplasts have twin phospholipid bilayers. This appears to have arisen by mitochondria and also chloroplasts entering eukaryotic cells via endocytosis. Both purple, aerobic bacteria (similar come mitochondria) and also photosynthetic bacteria (similar to chloroplasts) only have one phospholipid bilayer, but when they enter an additional cell via endocytosis, they room bound by a vesicle which creates the 2nd layer of their dual phospholipid bilayer.

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This video clip shows the procedure of endocytosis of aerobic bacteria and also photosynthetic bacteria very well.