Yes, cellular respiration occurs in the cells of living organisms. It is a biochemical process through which cells convert glucose (and other molecules) into adenosine triphosphate (ATP), the energy currency of the cell. This process typically involves three main stages:
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Glycolysis: This occurs in the cytoplasm and breaks down glucose into pyruvate, producing a small amount of ATP and NADH.
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Krebs Cycle (Citric Acid Cycle): This takes place in the mitochondria and processes the pyruvate into carbon dioxide while generating more ATP, NADH, and FADH2.
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Electron Transport Chain (ETC): This occurs in the inner mitochondrial membrane, where electrons from NADH and FADH2 are transferred through a series of proteins, ultimately producing a large amount of ATP and water as byproducts.
Cellular respiration can occur in the presence of oxygen (aerobic respiration) or in the absence of oxygen (anaerobic respiration), with aerobic respiration being more efficient in terms of ATP yield.