C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP
This is the overall chemical equation for cellular respiration, which occurs in the mitochondria of cells. In this process, glucose (C6H12O6) from food is broken down by oxygen (O2) to produce carbon dioxide (CO2), water (H2O), and ATP, the energy currency of cells. This reaction releases energy that is used by cells for various functions such as movement, growth, and reproduction. Overall, cellular respiration is essential for sustaining life and allowing organisms to carry out essential functions.
The given equation represents the process of cellular respiration, specifically aerobic respiration. Here are the steps involved in this process:
Step 1: Glycolysis
- The glucose molecule (C6H12O6) is broken down into two molecules of pyruvate.
- This step occurs in the cytoplasm and does not require oxygen.
- A small amount of ATP is produced, along with high-energy electron carriers (NADH).
Step 2: Pyruvate Decarboxylation
- Each pyruvate molecule is transported into the mitochondria.
- Each pyruvate molecule loses a carbon dioxide (CO2) molecule and is converted into acetyl CoA.
- This conversion generates one molecule of NADH.
Step 3: Citric Acid Cycle (also known as the Krebs cycle)
- The acetyl CoA enters the citric acid cycle.
- The cycle produces more carbon dioxide molecules (CO2).
- High-energy electron carriers (NADH and FADH2) are also generated.
- A small amount of ATP is produced.
Step 4: Electron Transport Chain (ETC)
- NADH and FADH2 molecules from previous steps donate their high-energy electrons to the electron transport chain.
- The electron transport chain is located in the inner mitochondrial membrane.
- The flow of electrons through the ETC creates a proton gradient.
- This gradient drives the production of ATP through a process called oxidative phosphorylation.
- Oxygen (O2) serves as the final electron acceptor and combines with electrons and protons to form water (H2O).
Overall, the reaction: C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP represents the breakdown of glucose to carbon dioxide and water, with the release of energy in the form of ATP during cellular respiration.