Which of these organelles produces H2O2 as a by-product
The Correct Answer and Explanation is:
Correct Answer: Peroxisome
Explanation
Peroxisomes are small, membrane-bound organelles found in nearly all eukaryotic cells. One of their primary functions is to break down long-chain fatty acids and detoxify harmful substances. During these metabolic processes, hydrogen peroxide (H₂O₂) is produced as a by-product.
The production of H₂O₂ occurs mainly during oxidative reactions carried out by enzymes called oxidases. For example, when fatty acids are broken down through a process called β-oxidation, peroxisomal oxidases transfer electrons directly to oxygen, forming hydrogen peroxide:
RH2+O2→R+H2O2\text{RH}_2 + O_2 \rightarrow R + H_2O_2
This reaction is vital for the metabolism of lipids and other compounds. However, hydrogen peroxide is toxic to cells due to its highly reactive nature. If not controlled, it can damage proteins, lipids, and DNA. To prevent this, peroxisomes contain another important enzyme called catalase. Catalase quickly converts H₂O₂ into water and oxygen:
2H2O2→2H2O+O22 H_2O_2 \rightarrow 2 H_2O + O_2
This dual enzyme system—oxidases and catalase—makes the peroxisome uniquely suited to manage oxidative reactions safely. Without peroxisomes, cells would be vulnerable to oxidative stress and damage.
Peroxisomes are also involved in other vital processes, including:
- Detoxification of alcohols in liver cells.
- Metabolism of amino acids and polyamines.
- Synthesis of plasmalogens, essential phospholipids in heart and brain tissues.
In summary, peroxisomes produce hydrogen peroxide as a by-product of fatty acid oxidation and other oxidative reactions. Their built-in safety mechanism involving catalase ensures that this potentially harmful compound is quickly neutralized, maintaining cellular health and function.
