Discuss The Significance Of Pentose Phosphate Pathway ?

1.	Discuss The Significance Of Pentose Phosphate Pathway ?
Answer» The pentose phosphate pathway differs from glycolysis since in the initial oxidation reactions, NADP+ rather than NAD+ is used. Pentose phosphate pathway is characterized by CO2 production, while CO2 is not produced at all in the glycolytic pathway. ATP is not generated by re-oxidation of NADPH + H+. Most of the NADPH produced can PROVIDE the REDUCING power for the synthesis of a series of compounds in cytosol like fatty acids, mevalonic acid and steroids. Conversion of pyruvate to oxaloacetate by malic enzyme may occur in the PRESENCE of these reducing equivalents. Moreover, the cycle provides pentose PHOSPHATES which may be utilized as precursors for the synthesis of NUCLEOTIDES and nucleic acids. Ribose-5-P, an intermediate of the pathway, reacts with ATP to form phosphoribosyl pyrophosphate (PRPP) which is used in nucleotide biosynthesis. If necessary, intermediate like glyceraldehyde-3-P and fructose-6-P may enter the process of glycolysis and are thereby aerobically degraded. Thus, the cycle provides a storehouse for the building elements of different areas of metabolism.

Answer»

The pentose phosphate pathway differs from glycolysis since in the initial oxidation reactions, NADP+ rather than NAD+ is used. Pentose phosphate pathway is characterized by CO2 production, while CO2 is not produced at all in the glycolytic pathway. ATP is not generated by re-oxidation of NADPH + H+.
Most of the NADPH produced can PROVIDE the REDUCING power for the synthesis of a series of compounds in cytosol like fatty acids, mevalonic acid and steroids. Conversion of pyruvate to oxaloacetate by malic enzyme may occur in the PRESENCE of these reducing equivalents.
Moreover, the cycle provides pentose PHOSPHATES which may be utilized as precursors for the synthesis of NUCLEOTIDES and nucleic acids. Ribose-5-P, an intermediate of the pathway, reacts with ATP to form phosphoribosyl pyrophosphate (PRPP) which is used in nucleotide biosynthesis.
If necessary, intermediate like glyceraldehyde-3-P and fructose-6-P may enter the process of glycolysis and are thereby aerobically degraded. Thus, the cycle provides a storehouse for the building elements of different areas of metabolism.

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