Final answer:
The peroxisome is the organelle in eukaryotic cells that breaks down hydrogen peroxide, a toxic byproduct of cellular metabolism, using the enzyme catalase to convert it into water and oxygen.
Step-by-step explanation:
The organelle that breaks down toxic hydrogen peroxide in eukaryotic cells is the peroxisome.Peroxisomes are critical to cellular function as they oversee oxidation reactions that decompose fatty acids and amino acids. A specialized enzyme within peroxisomes, known as catalase, plays a key role in rendering hydrogen peroxide harmless by converting it into water (H2O) and oxygen (O2).
As such, peroxisomes act as detox centers within eukaryotic cells, neutralizing various poisons including alcohol in the liver. Consequently, liver cells are rich in peroxisomes due to their detoxifying duties. Additionally, plant cells contain unique types of peroxisomes, such as glyoxysomes, which convert stored fats into sugars, showing their diverse metabolic functions across eukaryotic life.