Final answer:
In prokaryotic cells, the electron transport chains are found in the cell membrane, also known as the cytoplasmic membrane. This is different from eukaryotic cells, where these chains are located in the inner mitochondrial membrane. The prokaryotic cell membrane's integral proteins facilitate the electron transport processes necessary for ATP production.
Step-by-step explanation:
The location of electron transport chains in prokaryotes can be found in the cell membrane, also referred to as the plasma membrane or cytoplasmic membrane. Prokaryotes, such as bacteria, do not have membrane-bound organelles like mitochondria, which is where electron transport chains are found in eukaryotes. Instead, the cell membrane of prokaryotic cells performs this function. The integral proteins within the cell membrane are responsible for carrying out the electron transport chain processes that contribute to oxidative phosphorylation and ATP production through chemiosmosis.
In the context of endosymbiotic theory, it is suggested that mitochondria, which have their own DNA and ribosomes that resemble those of prokaryotes, evolved from an endosymbiotic bacterium. Consequently, mitochondria contain an inner membrane, which in eukaryotic cells is the location of the electron transport chain.
Therefore, the correct answer to the question about the location of electron transport systems in prokaryotes is D. the cytoplasmic membrane. Whereas, in a eukaryotic cell's mitochondria, the electron transport chain is embedded in the inner membrane. This inner membrane of mitochondria, originating from the bacterium's plasma membrane, is the site for integral proteins involved in the electron transport chain.