Microbodies:

• Single unit membrane bound, small spherical structuresl

One the basis of functions microbodies are of three types:

1. Spherosomes

• Hanstein (1880) first observed them and called as microsomes. Occur only in plant cells, and are major site of lipid storage and synthesis have lysosomes like activity, so also termed as plant lysosomes.

2. Peroxisomes or Uricosomes

Discovered by Rhodin and Tolbert

• In animal cells perosidase are concerned with peroxide metabolism. Urate oxidase, Amino acid oxidase and peroxidase catalyse the oxidation of amino acids producing H₂O₂. Catalase degrade the H₂O₂ into water and oxygen. In plants, peroxisomes occur in cells of green tissues and are concerned with photorespiration (glycolate pathway) and are also involved in B-oxidation of fatty acids.

3. Glyoxysomes

Discovered by Rhodin, Beever and Briedenbach.

• Occur only in plants especially in fatty seeds, guard cells of stomata and unripe fruits.
• Glyoxylic acid cycle takes place in Glyoxysome which was discovered by Kreb and Kornberg.

Signifiicance of glyoxylic acid cycle:

Involved in the formation of different organic acids during ripening of fruit. Converts fats into carbohydrates during germination of fatty seeds. May convert organic acids into carbohydrates (concerned with mechanism of closing of stomata during night).