Wednesday, February 27, 2019

Endosymbiotic Theory Essay

The endosymbiotic theory explains the evolution of the eukaryotic cadrephone and eukaryotic organelles by ph agocytocis of small prokaryotic cells. This theory states that some of the organelles in todays eukaryotic cells were formerly prokaryotic bacteria.In this theory, the first eukaryotic cell was probably an amoeba-like nucleated (probably DNA in a nucleoid region non an actual nucleus) prokaryotic cell that got nutrients by phagocytosis (engulfing nutrients or other cells) more or less of these unicellular amoeba-like organisms engulfed prokaryotic cells that somehow were non digested within the organism. In the serve of being engulfed the small cells would have been wrapped in membrane from the large cell, today we see double membranes in mitochondria and chloroplasts.The symbiotic relationship was advantageous because the entertain cell would have provided essential nutrients to the engulfed prokaryotic cell in exchange the smaller prokaryotic cell used these nutr ients to synthesize adenosine triphosphate molecules, this ATP was used as an capability source by the boniface cell. The smaller prokaryotic cell was given a safe environment as well as receiving nutrients from the larger host cell.The small prokaryotic cell developed a symbiotic (mutually beneficial) relationship with the host cell. This smaller prokaryotic cell would eventually become mitochondria or chloroplasts. Mitochondria would have been create when bacteria capable of aerobic respiration were ingested by a a lot larger cell. Chloroplasts formed when photosynthetic bacteria were ingested. They eventually lost their cell wall and much of their DNA because they were not of benefit within the host cell. Mitochondria and chloroplasts cannot grow outside their host cell in normal conditions because they in a flash depend on the cell for protection and nutrients. The reason we do not see this type of symbiotic relationship today is because conditions be much different now then they were on earth millions of years ago when this symbiotic event first took place.Scientists can support the endosymbiotic hypothesis because the characteristics of nothing organelles are so similar to those of prokaryotes. Energy organelles have their own posture of genetic information it is not foundenclosed in a nucleus but a circular ring in a nucleoid region just like prokaryotic DNA. Mitochondria and chloroplasts have their own ribosomes this would indicate that at one time energy organelles were able be self sufficient. Both organelles have a double membrane, a remnant of antique endosymbiotic event.Also when a cell divides by mitosis the energy organelles replicate the like way as do prokaryotic bacteria, by binary fission. Mitochondria and chloroplasts are about the same size as prokaryotic cells. The DNA of these energy organelles is different from the DNA found in the cells nucleus. There is some evidence of bacterial DNA in these energy organelles that sugg ests that long ago they were once prokaryotic cells.Biology, Neil A. Campbell & Jane B. ReeceBenjamin Cummings 7th discrepancy, 2006Investigating Biology, Neil A Campbell & Jane B.ReeceBenjamin Cummings 6th Edition 2007

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