Open In App

Peroxisomes: Definition, Structure, Diagram & Functions

Peroxisomes are membrane-bound organelles found in the cytoplasm of eukaryotic cells. They are small vesicles that contain digestive and oxidative enzymes. Peroxisomes are involved in various metabolic processes, particularly those related to lipid metabolism and detoxification.

It is made of a phospholipid bilayer with a fine granular matrix, which contains a variety of enzymes that carry out various metabolic processes. In this article, we will study peroxisomes, their structure with a well-labeled diagram, and the functions of peroxisomes in detail.



Peroxisomes Definition

Peroxisomes are small membrane-bound vesicles found in the cytoplasm of eukaryotic cells that are involved in lipid metabolism, energy metabolism, and chemical detoxification.



What are Peroxisomes?

Peroxisomes were discovered by the Belgian cell biologist Christian de Duve in 1967 in liver cells and named them peroxisomes, replacing the previously used term “microbodies”. Peroxisomes are membrane-bound vesicles that contain digestive enzymes and oxidative enzymes. These enzymes carry out several metabolic reactions, including energy metabolism, lipid metabolism, and detoxification. It also helps in maintaining cellular homeostasis. Peroxisomes got their name based on their involvement in generating and scavenging hydrogen peroxide activities. A human cell contains around 102–103 peroxisomes in the cytoplasm. Their dysfunction can lead to severe genetic disorders that can affect multiple aspects of metabolism.

Peroxisomes Diagram

A diagram of peroxisome is shown below:

Peroxisomes Structure

Peroxisomes are small membrane-bound cellular organelles that range in size from 0.1–1 µm diameter. They are involved in a variety of metabolic reactions, including lipid and energy metabolism. The structure of the peroxisomes is as follows:

Peroxisome Functions

Peroxiosme are responsible for carrying out various metabolic processes like lipid metabolism, energy metabolism and detoxification. Some of the important functions of the peroxisomes are discussed as follows:

Metabolism of Peroxisomes

Peroxisomes are small subcellular organelle that contain enzymes responsible for several metabolic processes. These processes include: 

Overall, peroxisomes contribute significantly to cellular metabolism by participating in key biochemical pathways that impact energy production, lipid metabolism, and detoxification.

Peroxisomal Disorders

Peroxisomal disorders are type of genetic diseases that affect one or more peroxisomal functions. Disorders are characterised by abnormal oxidation and toxic accumulation of very long-chain fatty acid. Common peroxisomal disorders include:

Some common symptoms of the diseases includes: Hearing and vision loss, Hypotonia, Neurological issues, seizures,  Adrenal insufficiency issues, Liver, kidney and bone diseases. Treatment include only supportive care and symptom alleviation as there is no cure.

Difference Between Peroxisome and Lysosomes

The differences between peroxisome and lysosomes are as follows:

Feature Peroxisomes Lysosomes
Location Cytoplasm Cytoplasm
Membrane Structure Single lipid bilayer Single lipid bilayer
Enzymatic Activities Involved in beta-oxidation, detoxification of hydrogen peroxide, plasmalogen synthesis, and more. Contain hydrolytic enzymes for digestion of cellular waste, macromolecules, and foreign materials.
Hydrogen Peroxide Handling Generate and detoxify hydrogen peroxide Do not generate hydrogen peroxide, primarily involved in its degradation.
Catalase Presence Contains catalase for hydrogen peroxide breakdown May contain various hydrolytic enzymes, but not catalase.
Role in Lipid Metabolism Involved in beta-oxidation of fatty acids Not directly involved in fatty acid breakdown, but may be associated with lipid metabolism in some contexts.
Involvement in Autophagy Can undergo autophagy for turnover May participate in autophagy but primarily involved in degrading cellular material.
Peroxisomal Targeting Signals (PTS) Proteins targeted by PTS for import into peroxisomes Proteins targeted by mannose-6-phosphate signals for import into lysosomes.
Function in Cellular Homeostasis Contributes to cellular homeostasis by detoxifying harmful substances and metabolic processes Plays a role in cellular waste management and recycling of cellular components.
Diseases Associated Peroxisomal disorders (e.g., Zellweger syndrome) Lysosomal storage disorders (e.g., Tay-Sachs disease)
Proliferation and Division Can multiply by autonomous replication and division Can undergo fission and fusion processes

Also Read:

FAQs on Peroxisomes

What is the Main Function of Peroxisomes?

The primary function of the peroxiosme is to carry out beta oxidation of the fatty acid, lipid metabolism, processing of reactive oxygen species and catabolism of D-amino acids, polyamines, and bile acids.

Where are Peroxisomes Found in the Cell?

Peroxisomes are small membrane bound organelles found in the cytoplasm of the eukaryotic cells. They contain at least 50 enzymes.

What are the Differences Between Lysosomes and Peroxisomes?

Peroxisomes are involved in lipid metabolism, detoxification, and the breakdown of hydrogen peroxide while Lysosomes are involved in cellular waste digestion and material recycling, containing digestive enzymes.

What are Peroxisomes Formed by?

Peroxisomes are formed by the following processes: Synthesis of membrane proteins and lipids, Selective import of proteins from the cytosol and Growth and division of the resulting organelles.

What are the Characteristics of Peroxisomes?

Peroxisomes are small membrane bound organelles that contain fine granular matrix. They are spherical structures with a phospholipid bilayer and contains various enzymes for metabolic processes.

What is an Example of a Peroxisome?

Some example of peroxisomes includes Yeast cells grown on sugar have small peroxisomes, Peroxisomes in liver cells remove hydrogen from alcohol and attach it to oxygen to create hydrogen peroxide.

What is the Difference Between Mitochondria and Peroxisomes?

Peroxisomes and mitochondria are different organelles within eukaryotic cells. Peroxisomes are involved in fatty acid metabolism and detoxification, while mitochondria generate ATP through cellular respiration.

What is the Structure of Peroxisome?

Peroxisomes are small organelles (0.1–1 µm in diameter) found in the cytoplasm of a cell. They are made up of a single lipid bilayer that surrounds a granular, protein-rich matrix.

What are Two Diseases of Peroxisomes?

Peroxisomal diseases are a group of metabolic diseases that are caused by the dysfunction of peroxisomes. Some examples include Zellweger syndrome, Infantile Refsum’s disease and Adrenoleukodystrophy.

Which Organ has More Peroxisomes?

Liver and Kidney contains the highest density of the peroxisomes as they are involved in toxin removal and waste filtration.


Article Tags :