Question

During glycolysis, the compound PGAL and DHAP are formed from fructose 1,6 diphosphate by
(a)Cleavage
(b)Isomerisation
(c)Phosphorylation
(d)Condensation

Answer 1

Hint: Fructose-1, 6-diphosphate (6C) splits up to form one molecule of each of 3C compounds, i.e., glyceraldehyde-3-phosphate or 3-phosphoglyceraldehyde (PGAL) and dihydroxyacetone-3-phosphate (DHAP) with the help of a reversible reaction catalyzed by fructose 1,6 - bisphosphate aldolase.

Complete answer:
The process by which one molecule of glucose is converted into two molecules of pyruvate, two hydrogen ions, and two molecules of water is called glycolysis, through which the 'high energy' molecules of ATP and NADH are synthesized. After the generation of pyruvate molecules, it proceeds to the link reaction, where acetyl-CoA is produced. Then comes the second stage of glycolysis where splitting of fructose 1,6-bisphosphate into glyceraldehyde 3-phosphate (GAP) and dihydroxyacetone phosphate (DHAP) occurs. The process in the previous reaction, where destabilization of the molecule occurs that allows the hexose ring to be split by aldolase into two triose sugars, those are dihydroxyacetone phosphate (a ketose) and glyceraldehyde 3-phosphate (an aldose). Aldolases are of two types: class I aldolases, present in animals and plants, and class II aldolases, present in fungi and bacteria which are used in different mechanisms in cleaving the ketose ring. The process of delocalization of electrons in the carbon-carbon bond cleavage associate with the alcohol group which results in carbanion stabilization by the structure of the carbanion itself.

Additional Information:
1) Louis Pasteur, a French scientist researched this issue during the 1850s and the results of his experiments began the long road to elucidating the pathway of glycolysis.
2) Eduard Buchner during the 1890s, provided insight into the component steps of glycolysis through the non-cellular fermentation experiments.
3) In the year 1905 to 1911, a series of experiments was done by scientists Arthur Harden and William Young who discovered more pieces of glycolysis, where they discovered that during alcohol fermentation, on glucose consumption the regulatory effects of ATP and the role of fructose 1,6-bisphosphate a compound that is a glycolysis intermediate.
4) Otto Meyerhof, Gustav Embden and many other biochemists had finally completed the puzzle of glycolysis by the 1940s.

So, the correct answer is, ‘Cleavage’.

Note: Hyperglycemia results from the low insulin levels seen in diabetes, where glucose levels in the blood rise and glucose are not properly taken up by cells, also through gluconeogenesis hepatocytes further contribute to this hyperglycemia. Hyperglycemia results through glycolysis in hepatocytes which controls hepatic glucose production, and then glucose is overproduced by the liver without having a means of being broken down by the body. Glycolysis is an important metabolic pathway, so glycolytic mutations are generally rare which means that the majority of occurring mutations result in an inability for the cell to respire, and causing the death of the cell at an early stage. Pyruvate kinase deficiency is an example of a mutation that occurs which leads to chronic hemolytic anemia. Many scientists are doing research to see the effect of mitochondrial metabolism and treat cancer by reducing glycolysis and thus starving cancerous cells in various new ways, including a ketogenic diet.