Cellular respiration is a series of metabolic reactions that take place in cells to convert nutrients into energy in the form of ATP (adenosine triphosphate). The correct order of cellular respiration can be broken down into the following main steps:
1. Glycolysis: This is the first step in cellular respiration and occurs in the cytoplasm of the cell. During glycolysis, a molecule of glucose is broken down into two molecules of pyruvate. This process does not require oxygen and produces a small amount of ATP.
2. Pyruvate Oxidation: In this step, the pyruvate molecules produced in glycolysis move into the mitochondria and undergo oxidation, resulting in the formation of acetyl CoA. This step is a bridge between glycolysis and the citric acid cycle.
3. Citric Acid Cycle (Krebs Cycle): Acetyl CoA enters the citric acid cycle, a series of chemical reactions that take place in the mitochondrial matrix. During this cycle, acetyl CoA is further broken down, leading to the production of ATP, NADH, and FADH2, which carry energy to the next step.
4. Electron Transport Chain (ETC): The final step of cellular respiration takes place in the inner mitochondrial membrane. The high-energy electrons from NADH and FADH2 are passed along the electron transport chain, generating a proton gradient. This gradient drives the synthesis of ATP through a process known as oxidative phosphorylation.
By following these steps in the correct order, cells can efficiently extract energy from nutrients through the process of cellular respiration.
