Tag: single membrane bound organelles

Xenobiotics are foreign compounds such as drugs and toxins are detoxify mainly in peroxisomes.

Glyoxysomes are microbodies which occur only in fat rich plant cells where they take part in $\beta$-oxidation of fats and perform glyoxylate cycle. Glyoxysomes characteristically possess catalase enzyme. The castor endosperm stores fat which is metabolised through glyoxysomes. Glyoxysomes will channel fats into krebs cycle through $\beta$-oxidation.

Spherosomes are single half unit membrane covered small spherical organelles which synthesize and store fats. They develop from smooth endoplasmic reticulum. Smooth endoplasmic reticulum lacks ribosomes and occurs in cells engaged in producing large quantity of lipids.

Glyoxysomes are microbodies which occur only in fat rich plant cells where they take part in $\beta$-oxidation of fats and perform glyoxylate cycle. Glyoxysomes possess catalase enzyme.

The peroxisomes are associated with the phenomenon of photorespiration and degradation of H$ _2$O$ _2$. Certain enzymes within the peroxisome, by using molecular oxygen, remove hydrogen atoms from specific organic substrates, in an oxidative reaction, producing hydrogen peroxide.
Photorespiration involves a complex network of enzyme reactions that exchange metabolites between chloroplasts, leaf peroxisomes and mitochondria.

Sphaerosomes are single membrane bound organelles which takes part in storage and synthesis of fats. They were discovered by Perner (1953). Sphaerosomes are spherical bodies with a diameter of about 0.5-1 mm. They contain granular contents, rich in lipids but also have some proteins. Some proteins are probably enzymatic and take part in the synthesis of fat. But they are not involved in photorespiration.

Peroxisomes contain oxidases. A major function of the peroxisome is the breakdown of very long chain fatty acids through $\beta$-oxidation. In animal cells, the very long fatty acids are converted to medium chain fatty acids, which are subsequently shuttled to mitochondria where they are eventually broken down to carbon dioxide and water.

Catalases and oxidases are found in peroxisomes. Peroxisomes contain oxidative enzymes, such as catalase, D-amino acid oxidase, and uric acid oxidase. A major function of the peroxisome is the breakdown of very long chain fatty acids through $\beta$-oxidation. 

Glyoxysomes are specialized peroxisomes found in plants, particularly in the fat storage tissues of germinating seeds and also in filamentous fungi. As in all peroxisomes, in glyoxysomes the fatty acids are hydrolyzed to acetyl-CoA by peroxisomal-oxidation enzymes. Besides peroxisomal functions, glyoxysomes possess additionally the key enzymes of glyoxylate cycle which accomplish the glyoxylate cycle bypass. Thus, glyoxysomes contain enzymes that initiate the breakdown of fatty acids and additionally possess the enzymes to produce intermediate products for the synthesis of sugars by gluconeogenesis. The seedling uses these sugars synthesized from fats until it is mature enough to produce them by photosynthesis. Glyoxysomes also participate in photorespiration and nitrogen metabolism in root nodules.

Glyoxysomes are specialized peroxisomes found in plants, particularly in the fat storage tissues of germinating seeds and also in filamentous fungi. As in all peroxisomes, in glyoxysomes the fatty acids are hydrolyzed to acetyl-CoA by peroxisomal oxidation enzymes. Besides peroxisomal functions, glyoxysomes possess additionally the key enzymes of glyoxylate cycle which accomplish the glyoxylate cycle bypass. Thus, glyoxysomes contain enzymes that initiate the breakdown of fatty acids and additionally possess the enzymes to produce intermediate products for the synthesis of sugars by gluconeogenesis. The seedling uses these sugars synthesized from fats until it is mature enough to produce them by photosynthesis. Glyoxysomes also participate in photorespiration and nitrogen metabolism in root nodules.