the majority of the atp molecules derived from the breakdown of glucose are generated by oxidative phosphorylation.
the majority of the atp molecules derived from the breakdown of glucose are generated by?
oxidative phosphorylation
glycolysis, which means “sugar splitting,” is the initial process in the cellular respiration pathway. glycolysis can be either an aerobic or anaerobic process. when oxygen is present, glycolysis continues along the aerobic respiration pathway. if oxygen is not present, then atp production is restricted to anaerobic respiration. the location where glycolysis, aerobic or anaerobic, occurs is in the cytosol of the cell. in glycolysis, a six-carbon glucose molecule is split into two three-carbon molecules called pyruvate. these carbon molecules are oxidized into nadh and atp. for the glucose molecule to oxidize into pyruvate, an input of atp molecules is required. this is known as the investment phase, in which a total of two atp molecules are consumed. at the end of glycolysis, the total yield of atp is four molecules, but the net gain is two atp molecules. even though atp is synthesized, the two atp molecules produced are few compared to the second and third pathways, krebs cycle and oxidative phosphorylation.
carbohydrate catabolism
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. 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. 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. 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. 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
complete glucose breakdown