The breakdown of pyruvate to give carbon dioxide, water and energy takes place in:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Mitochondria
Respiration breaks glucose down in two stages. In the cytoplasm, glucose is first split into pyruvate, which releases only a little energy. When oxygen is present, the pyruvate enters the mitochondria, where it is broken down completely into carbon dioxide and water, and most of the energy is released and stored as ATP. This is why mitochondria are called the powerhouse of the cell.
Why the other options are incorrect
Option (1) Cytoplasm — Incorrect. It is where glucose is split into pyruvate, the first stage, and not where pyruvate is broken down.
Option (2) Chloroplast — Incorrect. It carries out photosynthesis, making glucose from carbon dioxide and water.
Option (4) Nucleus — Incorrect. It holds the DNA and controls the activities of the cell.