Peroxisomes and Glyoxisomes | Similarities and Differences | Structure and Function

Peroxisome and Glyoxisomes:
1. Peroxisome:

Meaning of Word
Peroxi = Peroxide
Some (Soma)= Body

Discovery of Peroxisome:
Peroxisome was first described by J-Rhodin in 1954 and given the name Micro body. They were identified as organelles by De Duve in 1967. De Duve believed that the name "Micro body" was too general and chose the name Peroxisome because of its hydrogen peroxide (H2O2) production activity.

Definition of Peroxisome:
They are small cytoplasmic organelles and are simple sacs that contain enzymes known as oxidative enzymes.
Size of Peroxisome:
The Lysosome is about 0.5 micrometers in diameter.

Interesting Facts about Peroxisome:
• Peroxisome is surrounded by a single membrane.
• As membrane-bounded organelles are absent in prokaryotic cells, hence peroxisome is present only in Eukaryotic cells.
• They lie both in animal and plant cells.

Composition of Peroxisome:
It is composed of
:
i) Protein
ii) Lipids
iii) Enzymes: Contain mainly Oxidative Enzymes such as Oxidases, Catalases, Peroxidases, etc.

Structure of Peroxisome:
They are similar to Lysosomes, round and spherical, surrounded by a single membrane that encloses enzymes.

Functions of Peroxisome:
√ In Animals:
In animal cells, the lysosome helps in the formation and decomposition of hydrogen peroxide (H2O2) mainly in liver cells.

Explanation
Peroxisome contains enzymes such as oxidases which oxidize molecules (fatty acids and amino acids) found in the cell. Those oxidation reactions produce hydrogen peroxide. Another type of enzyme is present in Peroxisome known as Catalases, which convert Hydrogen Peroxide (H2O2) into Water and Oxygen and thus protecting cells from its corrosive effects.

√ In plants:
In green plants, photorespiration may occur in peroxisomes.

Why is Peroxisome named so?
The organelle produces peroxide (H2O2) in the cell, so it is named a Peroxisome.

Why is Peroxisome named Micro body?
De Duve isolated the Peroxisome from the liver cells of rats and believed that the name "Micro body" was too general and chose the name of Peroxisome because of its relationship with hydrogen peroxide.

2. Glyoxisome:
Discovery of Glyoxisome:
Glyoxisome was discovered by Harry Beevers in 1961.

Definition of Glyoxisome:
They are a form of Peroxisome (Glyoxisome, also known as plant Peroxisome) and a sac-like structure having enzymes present in the cytoplasm of the cell.

Interesting Facts about Glyoxisome

• Single Membrane bounded.
• Present only in Eukaryotic cells due to membrane-bounded nature.
• Only present in plant cells but absent in animal cells.

Composition of Glyoxisome:
Glyoxisome is composed of;
i) Protein
ii) Lipids
iii) Enzymes like glycolic acid oxidase and catalase.

Structure of Glyoxisome:
A single membrane-bounded or spherical sac-like structure is present in the cytoplasm of plant cells.

Functions of Glyoxisome:
i) Convert fatty acids into carbohydrates.
ii) In lipid-rich seeds (soya beans), glyoxisomes provide the site for the breakdown of Lipids.

Difference Between Peroxisome and Glyoxisome:
i) Peroxisome are present in animal cells while glyoxisomes are present in plant cells.
ii) Peroxisome does photorespiration in plants while Glyoxisome converts fatty acids into carbohydrates.
iii) Peroxisome was discovered by De Duve while Glyoxisome by Harry Beevers.

Similarities Between Peroxisome and Glyoxisome:
1. Both are single membrane-bounded.
2. Both are spherical.
3. Both contain enzymes.
4. Both have roles in plant cells.
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