Glucose metabolism
Glucose metabolism
Glucose occupies a central positionin the metabolismItisamajorsourceofmetabolicenergyItprovidesthe precursorsforthe synthesisof otherbiomoleculesItisstoredinpolymericform(asstarchinplantsandasglycogeninanimals)
Glucose occupies a central position in the metabolism It is a major source of metabolic energy. It provides the precursors for the synthesis of other biomolecules. It is stored in polymeric form (as starch in plants and as glycogen in animals)
Pathways of glucose metabolismGlycolysis“Glyco"_“lysis":breakdownofglucosemonomerGluconeogenesis“New"“genesis"of“glucose":synthesizingglucose“from scratch”Usedwhen supplyofglycogenisexhaustedGlycogensynthesisanddegradationStoringglucoselong-term andrecovering it laterPentosephosphatepathwayUsedtogeneratepentoses(5-Csugars)Startwithglucose
Glycolysis “Glyco” – “lysis”: breakdown of glucose monomer Gluconeogenesis “New” “genesis” of “glucose”: synthesizing glucose “from scratch” Used when supply of glycogen is exhausted Glycogen synthesis and degradation Storing glucose long-term and recovering it later Pentose phosphate pathway Used to generate pentoses (5-C sugars) Start with glucose Pathways of glucose metabolism
Properties of glucosemetabolism pathwaysEachstepisadifferentchemical reactionand iscatalyzedbyadifferentenzyme.Free energyreleased orconsumed is transferred to carriers likeATPand NADH.Rateof pathwayflux controlled by changingactivity ofindividualenzymes.Multiple steps → greater energy recoveryTwo general purposes of catabolicpathwaysConvert energy inmolecules tomoreusableformCreateintermediatestobeused inotherpathways
Each step is a different chemical reaction and is catalyzed by a different enzyme. Free energy released or consumed is transferred to carriers like ATP and NADH. Rate of pathway flux controlled by changing activity of individual enzymes. Multiple steps → greater energy recovery. Two general purposes of catabolic pathways Convert energy in molecules to more usable form. Create intermediates to be used in other pathways. Properties of glucose metabolism pathways
MajorPathways of Glucose UtilizationExtracellularmatrixputzoStructuralStorageGlycogen,and cell wallpolymerspolymerspolysaccharidesstarch,sucrosesynthesis of0structuralstoragepolymersGlucoseoxidationviaoxidationviapentosephosphateglycolysispathwayRibose5-phosphatePyruvateBuildingblocksforDNAandRNA
Major Pathways of Glucose Utilization Structural polymers Storage polymers Building blocks for DNA and RNA