Biology:Complete glucose breakdown
The complete glucose breakdown is a series of chemical reactions representing transformation of glucose to adenosine triphosphate during the normal phases of aerobic cellular respiration. It is mostly done inside the mitochondria to release the maximum amount of energy.[1]
Pyruvate is made from glucose during the glycolysis and transformed to an acetyl group during transition reaction. Glycolysis consists of ten enzymatic steps that occur in the cytoplasm of the cell. Glucose is converted to glucose-6-phosphate by hexokinase. This first step in the conversion of glucose to glucose-6-phosphate is a regulated step in glycolysis in which one ATP is used. From this phosphorylation, glucose in now trapped inside of the cell due to the negative charge from the phosphate group.[1] Glucose-6-phosphate is converted to fructose-6-phosphate by phosphoglucoisomerase. Then, fructose-6-phosphate is converted to fructose-1,6-bisphosphate by phosphofructokinase. The use of the enzyme phosphofructokinase is the committed step which is under the greatest control for glycolysis.[2] Fructose-1,6-bisphosphate is then converted to dihydroxyacetone phosphate (DHAP) and glycelaldehyde-3-phosphate (G3P) via aldolase. Next the DHAP is converted to G3P via triose phosphate isomerase. The two G3P now each are catalyzed by glyceraldehyde-3-phosphate dehydrogenase to produce two 1,3-bisphosphoglycerate. The two products then react with phosphoglycerate kinase to produce two 3-phosphoglycerate which then reacts with phosphoglycerate mutase to get two 2-phosphoglycerate. The two products then undergo an enolase reaction to get two phosphoenol pyruvate, which then reacts with pyruvate kinase to yield two pyruvate molecules.[3] Pyruvate kinase is the last step of glycolysis and is irreversible. A phosphate group is transferred from phosphoenol pyruvate to ADP which produces a pyruvate and ATP. [3] The pyruvates then undergo pyruvate oxidation to yield acetyl-CoA. The acetyl group is used in the Krebs cycle and the phase ends with the electron transport chain. During this stage, electrons are passed down the electron transport chain. Energy is released and captured for ATP production. The net result of this step is 34 ATP molecules[4]
References
- ↑ 1.0 1.1 "Cellular Respiration". Competition Science Vision 2 (17): 634–40. July 1999. https://books.google.com/books?id=IegDAAAAMBAJ&pg=PT85.
- ↑ "Snail reprograms glucose metabolism by repressing phosphofructokinase PFKP allowing cancer cell survival under metabolic stress". Nature Communications 8: 14374. February 2017. doi:10.1038/ncomms14374. PMID 28176759. Bibcode: 2017NatCo...814374K.
- ↑ 3.0 3.1 "Review of aerobic glycolysis and its key enzymes - new targets for lung cancer therapy". Thoracic Cancer 6 (1): 17–24. January 2015. doi:10.1111/1759-7714.12148. PMID 26273330.
- ↑ Beck, Kevin (July 25, 2018). "What Are the Four Phases of Complete Glucose Breakdown?". https://sciencing.com/four-phases-complete-glucose-breakdown-6195610.html.
See also
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