Lysosomes and Peroxisomes – Class 11 | Chapter – 10 | Biology Short Notes Series PDF

Lysosomes and Peroxisomes: Lysosomes and peroxisomes are organelles with many functions in all eukaryotic cells. Lysosomes contain hydrolytic enzymes (lysozyme) that degrade molecules, whereas peroxisomes contain enzymes such as catalase that convert hydrogen peroxide (H2O2) to water and oxygen and neutralize toxicity.

Lysosomes and Peroxisomes

Lysosome

A lysosome is a membrane-enclosed organelle inside the cell, which contains enzymes for the degradation of biological polymers like proteins, polysaccharides, lipids and nucleic acids. It is a spherical-shaped vesicle, functioning as the cell’s degradative system of both biological polymers and obsolete components inside the cytoplasm. Lysosomes are comparatively large in size; the size varies from 0.1-1.2 µm depending on the materials taken up for the digestion.

Peroxisome

A peroxisome is a membrane-enclosed organelle found in all eukaryotes, containing enzymes to break down metabolic hydrogen peroxides. Though peroxisomes are morphologically similar to lysosomes, they are comparatively small. The diameter of a peroxisome is 0.1 –1.0 µm. Proteins required by peroxisomes are synthesized by free ribosomes and obtained from the cytosol.

Difference Between Lysosomes and Peroxisomes

Lysosome Peroxisome
Lysosomes break down biological polymers like proteins and polysaccharides. Peroxisomes oxidize organic compounds, breaking down metabolic hydrogen peroxides.
Lysosomes consists of degradative enzymes. Peroxisomes consist of oxidative enzymes.
Lysosomes are responsible for the digestion in the cell. Peroxisomes are responsible for the protection of the cell against metabolic hydrogen peroxide.
Lysosomes are only found in animals. Peroxisomes are found in all eukaryotes.
Lysosomes are derived from either Golgi apparatus or endoplasmic reticulum. Peroxisomes are derived from the endoplasmic reticulum and are capable of replicating by themselves.
Lysosomes are comparatively large in size. Peroxisomes are small.
The proteins destined in the lysosomes are tagged with mannose 6-phosphate. The proteins destined in the peroxisomes are tagged with peroxisomal targeting signal (PTS).
Lysosomes are involved in endocytosis, autophagy, and phagocytosis. Peroxisomes are involved in biosynthesis of lipids and photorespiration.
Degradative reactions in the lysosomes do not generate energy. Oxidative reactions in peroxisomes generate ATP energy.

 

 


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