Which organelle is primarily responsible for energy production in plant and animal cells?

• A. Nucleus
• B. Chloroplasts
• C. Mitochondria
• D. Ribosome

Answer: (C)

Energy production in cells hinges on the mitochondria, the organelles that convert nutrients into ATP through cellular respiration. In both plant and animal cells, mitochondria carry out the processes that extract energy from glucose, including the citric acid cycle and the electron transport chain, to make ATP the cell can use for energy-requiring activities. Plants also have chloroplasts that capture light energy to synthesize sugars via photosynthesis, which can later be oxidized by mitochondria for energy, but the immediate energy currency comes from mitochondria. The nucleus stores genetic information and controls activities, while ribosomes build proteins; neither is the primary energy producer.