During cellular respiration, which organelle converts nutrients into ATP energy?

• A. Chloroplast
• B. Mitochondria
• C. Lysosome
• D. Golgi

Answer: (B)

ATP is the energy currency of the cell, and cellular respiration is how cells release energy from nutrients to make ATP. The organelle that carries out most of this ATP production is the mitochondria, often called the powerhouse of the cell. Inside the mitochondria, the Krebs cycle and the electron transport chain break down nutrients and transfer that energy into ATP. Chloroplasts are used for photosynthesis in plants, turning light energy into chemical energy—not the main place where ATP is produced during routine cellular respiration. Lysosomes digest waste materials, and the Golgi apparatus helps process and ship proteins. So the mitochondria are the primary site where nutrients are converted into ATP energy.