PowerPoint PresentationSlide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Regulated glycolytic reactions arenot at equilibrium in the cell Regulation pointsRegulation pointsB CG < 0Rate-limiting steps are regulated: reactions in the pathway that operate away from equilibrium are regulated. At these reactionsteps there is a build-up of substrates becausethe substrates are not converted to products fast enough. Typically these reactions areregulated.G ~ 0C DHexokinaseInhibitorsGlucose 6-phosphatePyruvate kinasePhosphofructokinaseATPCITRIC ACID CYCLE (ATP, citrate)ATP, citrate,PEPActivatorsADP, AMP,Fructose 2,6PRegulation of GlycolysisRegulatory Enzymes: exhibit decreased or increasedactivity in response to certain signals.Allosteric regulation: the enzymes activity is regulated throughreversible, noncovalent binding of a small molecule regulator (an allosteric modulator).GlycogenGlycolysisGluconeogenesisLactate(anaerobic)Pentose Phosphate PathwayThe Fates of GlucoseCitric acid cycle(aerobic)Gluconeogenesis: Synthesis of glucose from non-hexose precursors (lactate, fatty acids and amino acids)lactate Chapter 20. Figure 20-2Pentose Phosphate Pathway(a) Produces NADPH, a reducing agent needed for anabolic reactions.(b) Pentose type sugars. Required for the production nucleic acids Pentose Phosphate PathwayGlycolysisGlucoseGlycogenGlucoseGlycogen BreakdownGlycogen SynthesisGlycogen BreakdownRGlucoseGlycogenGlucoseGlycogen BreakdownGlycogen SynthesisGlycogen SynthesisRChapter 20. Figure 20-12Muscle glycogen reserves are rebuiltduring times of less intense activityGluconeogenesis in liverconverts lactate to glucoseHeavy activity in muscle consumes muscle glycogenThe liver is the central control point for regulating blood glucose levelsSuggested Reading: Chapter 23 869-884LiverBrainMuscle tissueglucoselactateDietary and intrinsic carbohydrates,proteins, and lipidsThe liver is the central control point for regulating blood glucose levelsglycogenlactateglycogenglucoserestactiveIt’s critical that blood glucose levelsare maintained within a defined concentration range.Low Blood Glucose:(Hungry. Several hours after eating)Increased gluconeogenesisIncrease glycogen break downEpinephrine (aka Adrenaline) mediates the fight or flight responseEffects similar to glucagon. It mobilizes glucose from glycogen.In contrast, it also promotes glucose catabolism in muscle tissue (for production of ATP for activity). Low Blood Glucose:(Panic reaction)Glucagon/Epinephrine control of glycogen synthesis/degradationOptional reading Page 449-454Signal cascade initiated by epinephrineSignal cascade initiated by epinephrineGlucagon control of glycolysis/gluconeogenesis(the fructose 2,6-bisphosphatate connection)Glucogon controls the production of fructose 2,6-bisphosphatateInsulin lowers blood glucose levelsHigh Blood
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