The endosymbiotic hypothesis for the origin of mitochondria (and chloroplasts) suggests that mitochondria are descended from specialized bacteria (probably purple nonsulfur bacteria) that somehow survived endocytosis by another species of prokaryote or some other cell type, and became incorporated into the cytoplasm. The endosymbiotic theory for the origin of mitochondria requires substantial modification the three identifiable ancestral sources to the proteome of mitochondria are proteins descended from the ancestral α-proteobacteria symbiont, proteins with no homology to bacterial orthologs, and diverse proteins with bacterial affinities not derived from α-proteobacteria. The chloroplasts of red algae, green algae, and plants evolved from an endosymbiotic cyanobacterium living within a mitochondria-containing eukaryotic host cell the evidence both mitochondria and chloroplasts can arise only from preexisting mitochondria and chloroplasts. Mitochondria and chloroplasts have striking similarities to bacteria cells they have their own dna, which is separate from the dna found in the nucleus of the cell and both organelles use their dna to produce many proteins and enzymes required for their function.
Chloroplasts are like tiny green factories within plant cells that help convert energy from sunlight into sugars, and they have many similarities to mitochondria the evidence suggests that these chloroplast organelles were also once free-living bacteria. Endosymbiosis and horizontal gene transfer the e histolytica cpn60 gene is contained in the nuclear genome and is closely related to the cpn60 gene of free-living proteobacteria and mitochondria what has just been described for mitochondria is also true in principle for chloroplasts. A mitochondria and chloroplasts in modern day eukaryotic cells descended from free-living bacteria that were engulfed by other prokaryotic cells 2 to 3 billion years ago b eukaryotic cells evolved from prokaryotic cells due to competition for resources in the harsh environment of a barren earth before its atmosphere contained oxygen. Was the mitochondrion or chloroplast first mitochondria evolved before chloroplasts between their free living ancestors- $\alpha$-proteobacterium and cyanobacteria, the latter seems to be older in evolution i have following points to support this argument.
Both the genetic and energy-converting systems of chloroplasts and mitochondria are descended, with little modification, from those of the free-living bacteria that these organelles once were the existence of these cytoplasmic genomes is consistent with, and counts as evidence for, the endosymbiont hypothesis. Mitochondria chloroplasts hydrogenosomes eukaryote origin have evolved: a free-living complex ﬂagellar counterpart a free- dria he attributed to the nucleus, which he thought descended from an independent endosymbiosis that preceded the plastid (mereschkowsky, 1910. Chloroplasts in situ are surrounded by jackets of a material which does not contain chlorophyll the chlorophyll-bearing inner structure lacks motion while the jackets constantly change shape. Chloroplasts are located in the cytoplasm of plants cells whilst mitochondria are found in animal cells in short, they both produce atp (adenosine triphosphate) which is lik e the currency of energy for a living organism you can think of them as little power stations for the cell. Mitochondria and chloroplasts are descended from free-living bacteria, with mitochondria closely related to α-proteobacteria and chloroplasts closely related to cyanobacteria figure 2 shows the mitochondrial cytochrome c and bacterial cytochrome c2.
An endosymbiont or endobiont the most common examples of obligate endosymbioses are mitochondria and chloroplasts some human parasites, additionally, both host and symbiont cell growth were much greater than free-living richelia intracellularis or symbiont-free hemiaulus spp. In most vascular plant chloroplasts, the thylakoids are arranged in stacks called grana,  though in certain c 4 plant chloroplasts  and some algal chloroplasts, the thylakoids are free floating. Both chloroplasts and mitochondria are thought to have evolved from free-living prokaryotic cells (bacteria) that somehow became swallowed by a larger cell by endocytosis.
In lynn’s view, the chloroplast originated as a free-living cyanobacterium engulfed by a protozoan and reduced through time to metabolic slavery similarly, she hypothesized that the mitochondrion descended from an endosymbiotic bacterium capable of aerobic respiration. Like mitochondria, chloroplasts are descended from a free-living prokaryotic organism that entered the eukaryotic lineage through endosymbiosis during the course of their evolution, chloroplasts relinquished the majority of their genes so that now, 90% of chloroplast proteins are encoded in the nucleus ( leister, 2003 . It is more closely related to free-living cyanobacteria than to chloroplasts (marin, 2005) both mitochondria and chloroplasts are sensitive to antibiotics which affect although it was originally thought that these primitive eukaryotes were descended from ancestors which diverged after the evolution of the eukaryotic nucleus and. Cellular organelles (eg, plastids and mitochondria) are descended from free-living organisms 2 7kh8qlyhuvlw\ri&doliruqld0xvhxpri3dohrqwrorj\ %hunhoh\ dqgwkh5hjhqwvriwkh8qlyhuvlw\ri&doliruqld zzz xqghuvwdqglqjvflhqfh ruj if chloroplasts contain their own dna and reproduce by splitting in two, could it be that these.
Mitochondria originated by a endosymbiotic event when a bacterium was captured by a eukaryotic cell sequence homologies suggest that mitochondria and chloroplasts evolved separately, which is an obligate intracellular parasite that is probably descended from free-living bacteria. Chloroplasts, like mitochondria, bear a striking resemblance to bacteria scientists became convinced that chloroplasts (below right), like mitochondria, evolved from symbiotic bacteria — specifically, that they descended from cyanobacteria (above right), the light-harnessing small organisms that abound in oceans and fresh water. Protists with modified mitochondria two groups of protists - the diplomonads (figure 7) and the parabasalids (figure 8) have highly modified mitochondria the evidence suggests that each group is monophyletic but what is less clear is how closely related these two groups are to each other.