Cellular Respiration: The Powerhouse of
the Cell
Introduction
Cellular respiration is a set of metabolic reactions and processes that take place in the cells of
organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP),
and then release waste products. The reactions involved in respiration are catabolic reactions,
which break down large molecules into smaller ones, releasing energy in the process.
Process of Cellular Respiration
Cellular respiration primarily occurs in the mitochondria, often referred to as the “powerhouse
of the cell”. It consists of three main stages: Glycolysis, the Krebs Cycle, and the Electron
Transport Chain.
Glycolysis
Glycolysis is the first stage of cellular respiration and it occurs in the cytoplasm. It is the
process of breaking down a glucose molecule into two pyruvate molecules. This process
produces 2 ATP molecules and 2 NADH molecules.
Krebs Cycle
The Krebs Cycle, also known as the Citric Acid Cycle, takes place in the mitochondria. It
involves the oxidation of pyruvate into carbon dioxide and water. For each glucose molecule,
this cycle produces 2 ATP molecules, 6 NADH molecules, and 2 FADH2 molecules.
Electron Transport Chain
The Electron Transport Chain is the final stage of cellular respiration. It takes place in the
inner mitochondrial membrane. Here, the NADH and FADH2 molecules produced in the
previous stages pass their electrons through a series of proteins. This process drives the
production of 32-34 ATP molecules, the main energy carriers in cells.
Conclusion
Cellular respiration is a vital process for all living organisms. It allows cells to convert the
energy stored in glucose into a form that the cell can use - ATP. Understanding this process is
fundamental to the study of biology, shedding light on how organisms meet their energy
needs.