Which structure performs the function of mitochondria in bacteria?
A. Nucleoid
B. Ribosomes
C. Cell wall
D. Mesosomes

Hint:This is the bacterial cell organelle that is found in the cell membrane of the prokaryotic cells. Their structure is similar to the eukaryotic mitochondria.

Complete answer :
Mitochondria are the special structures. They are the important part of the cell and also called a powerhouse of the cell. Mitochondria helps in respiration. As bacteria lacks both mitochondria and chloroplasts. Mesosomes structure formed by the infoldings of the plasma membrane. Mesosomes also help in increasing the surface area for the plasma membrane. The structure of mesosomes consists of the tubules and vessels. These are generally found in the site of cell division. Mesosomes perform the function of mitochondria in bacteria. This is because mesosomes are analogous to the eukaryotic mitochondria and mesosomes also help in carrying out the respiration in the bacteria.

Additional information:
Nucleoids are found in prokaryotic cells and they control the activity of the cell and help in reproduction. Nucleoid found where the respiration and transcription of DNA takes place. Ribosomes decodes the message and helps in the formation of the peptide bonds. Ribosomes are helpful in synthesizing proteins and they are also called a “protein factory”. Cell wall is rigid, flexible and tough. It provides the structural support and protection to the cell.

Thus, the correct answer is option D. i.e., Mesosomes.

Note: Mesosomes are absent in eukaryotic cells but they are analogous to the eukaryotic mitochondria. Mesosomes help in the respiration in the bacteria. They are very rich in enzymes and folding of the bacterial cell membrane.