other pathways this article concentrates on the catabolic role of glycolysis with regard to converting potential chemical energy to usable chemical energy during the oxidation of glucose to pyruvate. many of the metabolites in the glycolytic pathway are also used by anabolic pathways, and, as a consequence, flux through the pathway is critical to maintain a supply of carbon skeletons for biosynthesis. the following metabolic pathways are all strongly reliant on glycolysis as a source of metabolites: and many more. pentose phosphate pathway, which begins with the dehydrogenation of glucose-6-phosphate, the first intermediate to be produced by glycolysis, produces various pentose sugars, and nadph for the synthesis of fatty acids and cholesterol. glycogen synthesis also starts with glucose-6-phosphate at the beginning of the glycolytic pathway. glycerol, for the formation of triglycerides and phospholipids, is produced from the glycolytic intermediate glyceraldehyde-3-phosphate. various post-glycolytic pathways: fatty acid synthesis cholesterol synthesis the citric acid cycle which in turn leads to: amino acid synthesis nucleotide synthesis tetrapyrrole synthesis although gluconeogenesis and glycolysis share many intermediates the one is not functionally a branch or tributary of the other. there are two regulatory steps in both pathways which, when active in the one pathway, are automatically inactive in the other. the two processes can therefore not be simultaneously active. indeed, if both sets of reactions were highly active at the same time the net result would be the hydrolysis of four high energy phosphate bonds (two atp and two gtp) per reaction cycle. nad+ is the oxidizing agent in glycolysis, as it is in most other energy yielding metabolic reactions (e.g. beta-oxidation of fatty acids, and during the citric acid cycle). the nadh thus produced is primarily used to ultimately transfer electrons to o2 to produce water, or, when o2 is not available, to produced compounds such as lactate or ethanol (see anoxic regeneration of nad+ above). nadh is rarely used for synthetic processes, the notable exception being gluconeogenesis. during fatty acid and cholesterol synthesis the reducing agent is nadph. this difference exemplifies a general principle that nadph is consumed during biosynthetic reactions, whereas nadh is generated in energy-yielding reactions. the source of the nadph is two-fold. when malate is oxidatively decarboxylated by “nadp+-linked malic enzyme" pyruvate, co2 and nadph are formed. nadph is also formed by the pentose phosphate pathway which converts glucose into ribose, which can be used in synthesis of nucleotides and nucleic acids, or it can be catabolized to pyruvate. glycolysis in disease diabetes cellular uptake of glucose occurs in response to insulin signals, and glucose is subsequently broken down through glycolysis, lowering blood sugar levels. however, the low insulin levels seen in diabetes result in hyperglycemia, where glucose levels in the blood rise and glucose is not properly taken up by cells. hepatocytes further contribute to this hyperglycemia through gluconeogenesis. glycolysis in hepatocytes controls hepatic glucose production, and when glucose is overproduced by the liver without having a means of being broken down by the body, hyperglycemia results. genetic diseases glycolytic mutations are generally rare due to importance of the metabolic pathway; the majority of occurring mutations result in an inability of the cell to respire, and therefore cause the death of the cell at an early stage. however, some mutations (glycogen storage diseases and other inborn errors of carbohydrate metabolism) are seen with one notable example being pyruvate kinase deficiency, leading to chronic hemolytic anemia. cancer malignant tumor cells perform glycolysis at a rate that is ten times faster than their noncancerous tissue counterparts. during their genesis, limited capillary support often results in hypoxia (decreased o2 supply) within the tumor cells. thus, these cells rely on anaerobic metabolic processes such as glycolysis for atp (adenosine triphosphate). some tumor cells overexpress specific glycolytic enzymes which result in higher rates of glycolysis. often these enzymes are isoenzymes, of traditional glycolysis enzymes, that vary in their susceptibility to traditional feedback inhibition. the increase in glycolytic activity ultimately counteracts the effects of hypoxia by generating sufficient atp from this anaerobic pathway. this phenomenon was first described in 1930 by otto warburg and is referred to as the warburg effect. the warburg hypothesis claims that cancer is primarily caused by dysfunctionality in mitochondrial metabolism, rather than because of the uncontrolled growth of cells. a number of theories have been advanced to explain the warburg effect. one such theory suggests that the increased glycolysis is a normal protective process of the body and that malignant change could be primarily caused by energy metabolism. this high glycolysis rate has important medical applications, as high aerobic glycolysis by malignant tumors is utilized clinically to diagnose and monitor treatment responses of cancers by imaging uptake of 2-18f-2-deoxyglucose (fdg) (a radioactive modified hexokinase substrate) with positron emission tomography (pet). there is ongoing research to affect mitochondrial metabolism and treat cancer by reducing glycolysis and thus starving cancerous cells in various new ways, including a ketogenic diet. interactive pathway map the diagram below shows human protein names. names in other organisms may be different and the number of isozymes (such as hk1, hk2, ...) is likely to be different too. click on genes, proteins and metabolites below to link to respective articles. [[file: |alt=glycolysis and gluconeogenesis edit]] glycolysis and gluconeogenesis edit the interactive pathway map can be edited at wikipathways: "glycolysisgluconeogenesis_wp534". alternative nomenclature some of the metabolites in glycolysis have alternative names and nomenclature. in part, this is because some of them are common to other pathways, such as the calvin cycle. this article alternative 1 glucose glc dextrose 2 glucose-6-phosphate g6p 3 fructose-6-phosphate f6p 4 fructose-1,6-bisphosphate f1,6bp fructose 1,6-diphosphate fbp; fdp; f1,6dp 5 dihydroxyacetone phosphate dhap glycerone phosphate 6 glyceraldehyde-3-phosphate gadp 3-phosphoglyceraldehyde pgal; g3p; galp; gap; tp 7 1,3-bisphosphoglycerate 1,3bpg glycerate-1,3-bisphosphate,glycerate-1,3-diphosphate,1,3-diphosphoglycerate pgap; bpg; dpg 8 3-phosphoglycerate 3pg glycerate-3-phosphate pga; gp 9 2-phosphoglycerate 2pg glycerate-2-phosphate 10 phosphoenolpyruvate pep 11 pyruvate pyr pyruvic acid conjugate base structure of glycolysis components in fischer projections and polygonal model the intermediates of glycolysis depicted in fischer projections show the chemical changing step by step. such image can be compared to polygonal model representation. another comparation of fischer projections and poligonal model in glycolysis is shown in a video. video animations in the same channel in youtube can be seen for another metabolic pathway (krebs cycle) and the representation and applying of polygonal model in organic chemistry glycolysis - structure of anaerobic glycolysis components showed using fischer projections, left, and polygonal model, right. the compounds correspond to glucose (glu), glucose 6-phosphate (g6p), fructose 6-phosphate (f6p), fructose 1,6-bisphosphate ( f16bp), dihydroxyacetone phosphate (dhap), glyceraldehyde 3-phosphate(ga3p), 1,3-bisphosphoglycerate (13bpg), 3-phosphoglycerate (3pg), 2-phosphoglycerate (2pg), phosphoenolpyruvate (pep), pyruvate (pir), and lactate (lac). the enzymes which participate of this pathway are indicated by underlined numbers, and correspond to hexokinase (1), glucose-6-phosphate isomerase (2), phosphofructokinase-1 (3), fructose-bisphosphate aldolase (4), triosephosphate isomerase (5), glyceraldehyde-3-phosphate dehydrogenase (5), phosphoglycerate kinase (7), phosphoglycerate mutase (8), phosphopyruvate hydratase (enolase) (9), pyruvate kinase (10), and lactate dehydrogenase (11). the participant coenzymes (nad+, nadh + h+, atp and adp), inorganic phosphate, h2o and co2 were omitted in these representations. the phosphorylation reactions from atp, as well the adp phosphorylation reactions in later steps of glycolysis are shown as ~p respectively entering or going out the pathway. the oxireduction reactions using nad+ or nadh are observed as hydrogens “2h” going out or entering the pathway.