Cellular respiration is a metabolic process through which cells convert glucose (or other organic molecules) into energy, specifically in the form of adenosine triphosphate (ATP). This process occurs in both aerobic (with oxygen) and anaerobic (without oxygen) conditions.
The general stages of cellular respiration include:
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Glycolysis: This occurs in the cytoplasm and involves the breakdown of glucose into pyruvate, generating a small amount of ATP and NADH in the process.
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Krebs Cycle (Citric Acid Cycle): This occurs in the mitochondria and processes the pyruvate into carbon dioxide while transferring high-energy electrons to carrier molecules (NADH and FADHâ‚‚).
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Electron Transport Chain: This is the final stage that takes place in the inner mitochondrial membrane. The high-energy electrons from NADH and FADHâ‚‚ are transferred through a series of proteins, creating a proton gradient that drives the synthesis of ATP via ATP synthase. Water is produced as a byproduct when electrons combine with oxygen.
For organisms that undergo anaerobic respiration, such as certain bacteria and yeast, the process may involve fermentation pathways, which convert glucose to energy without reliance on oxygen.
Overall, cellular respiration is crucial for cells as it provides the energy needed for various biological processes.