Prokaryotes vs.. Eukaryotes

A brief overview of the subtle differences between Prokaryotes and Eukaryotes.

Prokaryotes and eukaryotes are so different, yet so much the same. Many believe prokaryotes are a distant cousin to eukaryotes from far back in the evolutionary time line. Over the millennia the two groups started to branch away from each other, the prokaryotes silently working away at their jobs, minding their own business while their embarrassing relatives were letting in any random bacteria that came their way. Then, inevitably, they ask if they can crash there a while with a few of their friends. After a few hundred years, there comes a vague suspicion that they’re all freeloaders. “If you’re going to stay here you’ll have to work for that privilege!” says the eukaryote finally putting its metaphorical foot down. “Fine” say the bacteria and create an advanced and enlightened society. The prokaryote yells over the fence “Evolve! You party animals.” Unfortunately, the eukaryote did not bother to develop ears. This is more or less how the eukaryote developed give or take a few artistic liberties. What makes a eukaryote so different from a prokaryote is its variety of organelles; many of which are believed to once have been prokaryotes in their own right. One of the most distinctive organelles is the mitochondria. Mitochondria, or mitochondrion, are the energy producing organelles of the eukaryotic cell. Mitochondria posses a double membrane leading many scientists to believe that the mitochondria used to be prokaryotic cells that where swallowed up by a larger cell. This double membrane serves to increase surface area on the inside of the cell. This convoluted internal membrane is called the cristae of the mitochondria. This is coiled up so such a large extent that it makes up one third of an eukaryotic cell’s total membrane. This membrane projects into an inner space called the matrix. The matrix houses the mitochondrial DNA and ribosomes. The existence of mitochondrial DNA further supports the theory that the mitochondria used to be separate cells. The matrix is also home to highly concentrated mixtures of enzymes that assist in breaking down carbohydrates. This in turn produces ATP, which is the main power source of the cell. This process is called cellular respiration. How doe one go about acquiring said carbohydrates? Well, animal cells simply engulf other cells through phagocytosis. Plant cells, on the other hand are enlightened and “autotrophic.” They do not need to make use of such barbaric means in order to acquire food. All they need is some CO2 from the atmosphere, which is easy enough to come by these days. Put them in the sun then just add water and poof, instant energy. Of course, the process is far more complicated than that. The secret to their evolutionary success is chloroplasts, the miniature miracle working organelles. These to are composed of a double membrane and their own DNA. The double membrane encloses an open space called the stroma. This, in turn, houses a third membrane formed into thylakoids. It is in this third membrane that the magic happens. Carbon Dioxide goes in ATP and NADP come out.  I will waste little time on further elaboration on said subject. It suffices to say that pigments in chloroplasts called chlorophyll capture sunlight and through a complex process converted into usable, chemical energy such as carbohydrates. This all fine and dandy for eukaryotes, but prokaryotes need organelles too. Fortunately, they happen to share a few with their crazy cousins.

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