Splitting of Sugar, Oxidation/ Reduction & ATP Generation
Date Uploaded: 02/14/2020
Tags: homeworkclinic.com Homework Clinic HWC Splitting of Sugar glycolysis The fructose bisphosphate molecule G3P glyceraldehyde 3-phosphate Electron Carrier Molecules Phosphorylation nicotinamide adenine dinucleotide oxidation reaction reduction reaction phosphoenolpyruvate ATP
The next reaction shows us the meaning of "glycolysis" or the splitting of glucose. The fructose bisphosphate molecule is split into two molecules each containing 3 carbons as the backbone. FBP is split into two 3-carbon molecules called G3P, or glyceraldehyde 3-phosphate. Notice that the phosphate groups are still attached to the original carbon 1 and carbon 6 which were present in the glucose molecule. Electron Carrier Molecules & Phosphorylation The next reaction involves oxidation, or the loss of electrons. High energy electrons from hydrogen atoms are removed and transferred to an electron carrier molecule. NAD* (nicotinamide adenine dinucleotide) is reduced to NADH plus H. Two hydrogen atoms are removed from each G3P molecule. This is the oxidation reaction. NAID+ accepts two hydrogen electrons and 1 proton (hydrogen ion or H+) while a second H+ is left in the aqueous solution of the cytoplasm. This is the reduction reaction. As part of these oxidation-reduction reactions, an inorganic phosphate group is added to each G3P molecule. Inorganic phosphate (1-13PO4) is utilized rather than a phosphate group from ATP. Inorganic phosphate is freely available in the cytoplasm. The new molecule now contains two phosphate groups and is called 1,3-bisphosphoglycerate (BPG). 1st Substrate Level Phosphorylation, Rearrangement of 3PG, 2nd Substrate Level Phosphorylation & Molecular Scorecard Finally, we are ready to harvest some ATP molecules. One phosphate group at a time is harvested from each BPG molecule. This phosphate group is added to a precursor molecule of ATP. The phosphate from BPG is attached to ADP, and in the process ADP is converted to ATP. The resulting molecule is called 3-phosphoglycerate (3PG). 3PG is rearranged into PEP (phosphoenolpyruvate) by the removal of a water molecule and the transfer of the phosphate group to the middle carbon atom. A molecule of water is released as well during this reaction.
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