Week 5

       From this week , I studed about the  endosymbiotic theory which is a theory stating that the eukaryotes evolved through a process whereby different types of free-living prokaryotes became incorporated inside larger prokaryotic cells and eventually developed into mitochondria, chloroplasts, and possibly other organelles.The Endosymbiotic Theory was first postulated by Lynn Margulis in the 1967. Dr. Margulis was doing reserarch on the origin of eukaryotic cells. She looked at all the data about prokaryotes, eukaryotes, and organelles.

       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.Then, later, a similar event brought chloroplasts into some eukaryotic cells, creating the lineage that led to plants. Despite their many similarities  mitochondria and chloroplasts  aren't free-living bacteria anymore.The first eukaryotic cell evolved more than a billion years ago. 

        Even though both organelles are found in eukaryotic cells, both mitochondria and chloroplast have characteristics often found in prokaryotic cells. These prokaryotic cell characteristics include: an enclosed double membrane, circular DNA, and bacteria-like ribosomes.

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