What is the function of the mitochondria?

• A. Cellular respiration, turns nutrients into energy
• B. Calcium storage
• C. Genetic information storage
• D. Protein synthesis

Answer: (A)

The mitochondria generate energy for the cell by carrying out cellular respiration, turning nutrients into ATP. They host the citric acid cycle and oxidative phosphorylation, where fuel molecules are broken down and the energy released is used to drive ATP synthesis; oxygen serves as the final electron acceptor to keep the process efficient. While mitochondria do contain their own DNA and ribosomes and can make a few proteins, and calcium storage is also associated with them, the central, defining role in this context is producing ATP to power cellular activities. Protein synthesis mainly occurs on cytosolic ribosomes and the rough endoplasmic reticulum, not in mitochondria.