Where does cellular respiration take place? A. Chlorophyll B. Mitochondria C. Nucleus
The correct answer and explanation is :
The correct answer is B. Mitochondria.
Explanation:
Cellular respiration is a process through which cells convert nutrients, primarily glucose, into energy in the form of adenosine triphosphate (ATP). This process occurs in the mitochondria, often referred to as the “powerhouses” of the cell due to their crucial role in energy production.
Cellular respiration involves several stages: Glycolysis, Citric Acid Cycle (Krebs Cycle), and Electron Transport Chain (ETC).
- Glycolysis takes place in the cytoplasm of the cell. During this initial stage, glucose is broken down into two molecules of pyruvate, releasing a small amount of ATP and NADH. Glycolysis does not require oxygen and is anaerobic.
- The Citric Acid Cycle (Krebs Cycle) and Electron Transport Chain (ETC) take place inside the mitochondria. The pyruvate molecules produced from glycolysis are transported into the mitochondria, where they are further broken down. In the Citric Acid Cycle, the pyruvate is completely oxidized, producing carbon dioxide, NADH, FADH2, and a small amount of ATP.
- The Electron Transport Chain (ETC) is located along the inner mitochondrial membrane. Here, the NADH and FADH2 produced earlier donate electrons to the chain, which powers the production of ATP through a process called oxidative phosphorylation. Oxygen is essential for this stage, as it acts as the final electron acceptor, forming water when combined with electrons and protons (hydrogen ions).
The mitochondria are uniquely equipped for this process due to their double membrane structure. The inner membrane has a high surface area due to folds called cristae, which increase the efficiency of ATP production. This setup allows mitochondria to efficiently generate ATP, which powers various cellular activities.
In contrast, chlorophyll (A) is involved in photosynthesis in plant cells, and the nucleus is responsible for storing genetic material and coordinating cell activities but does not participate directly in cellular respiration. Thus, the mitochondria are the main site where cellular respiration occurs.