LESSON-6-CELLULAR-RESPIRATION-handouts.pdf
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Cellular Respiration “Harvesting Chemical Energy” Prepared by: Medelyn G. Bacus Course Instructor 01 Introduction ENERGY Cells usable source of energy is in the form of ATP Adenosi...
Cellular Respiration “Harvesting Chemical Energy” Prepared by: Medelyn G. Bacus Course Instructor 01 Introduction ENERGY Cells usable source of energy is in the form of ATP Adenosine Triphosphate SOURCES OF GLUCOSE 1. STARCH CONSUMPTION 2. GLYCOGEN CELLULAR RESPIRATION a metabolic pathway that uses glucose to produce adenosine triphosphate (ATP), an organic compound the body can use for energy. 3 PATHWAYS OF CELLULAR RESPIRATION 1. GLYCOLYSIS 2. (Pyruvate oxidation) CITRIC ACID CYCLE/TCA/KREBS CYCLE 3. OXIDATIVE PHOSPHORYLATION : ETC and CHEMIOSMOSIS GLYCOLYSIS “sugar splitting” the process in which glucose is broken down to produce energy. Location : cytosol ENERGY INVESTMENT PHASE 2 ATP are consumed. STEP 1 : PHOSPHORYLATION STEP 2 : ISOMERIZATION STEP 3 : SECOND PHOSPHORYLATION STEP 4 : CLEAVAGE STEP 5 : CONVERSION OF DHAP into GADP/G3P ENERGY PAY-OFF PHASE 4 ATP’s are recovered NET GAIN= 2ATP 2 NADH STEP 6: OXIDATION STEP 7: DEPHOSPHORYLATION STEP 8 : PHOSPHATE TRANSFER STEP 9 : DEHYDRATION STEP 10 : SECOND DEPHOSPHORYLATION ENERGY INPUT AND OUTPUT OF GLYCOLYSIS GLYCOLYSIS STEPS 1- 5 ENERGY INVESTMENT PHASE Glucose + 2ATP 2G3P STEPS 6- 10 ENERGY PAYOFF PHASE 2 GADP/G3P 2 pyruvate + 4ATP Net = 2 ATP/ glucose molecule + 2NADH GLYCOLYSIS STEPS 1- 5 ENERGY INVESTMENT PHASE Glucose + 2ATP 2G3P STEPS 6- 10 ENERGY PAYOFF PHASE 2 GADP/G3P 2 pyruvate + 4ATP Net = 2 ATP/ glucose molecule + 2NADH a.k.a. Krebs Cycle/ Tricarboxylic acid cycle (TCA) -Hans Kreb CITRIC ACID CYCLE -completes the energy-yielding oxidation of organic molecules. Takes place in mitochondrial matrix. - only less than a quarter of the chemical energy in glycolysis is only produced. PYRUVATE OXIDATION RESULTS 3 NADH 1 FADH2 1 GTP Per ONE GLUCOSE MOLECULE 6 NADH 2 FADH2 FADH2 2 ATP OXIDATIVE PHOSPHORYLATION “ ELECTRON CARRIER” in ETC -NADH -FADH2 is the process of ATP formation, when electrons are transferred by electron carriers from NADH or FADH2 to oxygen” GOAL - Couple energy stored in electron acceptors to a protein gradient that drives ATP Synthesis. ELECTRON TRANSPORT CHAIN- Collection of molecules embedded in the inner mitochondrial membrane FMN- Flavin Mononucleotide Fe-S- Iron sulfur protein Q- Ubiquinone (mobile) ELECTRON TRANSPORT CHAIN EASE THE FALL OF ELECTRONS ATP YIELD GLYCOLYSIS ATP 2 /4 NADH 2 Pyruvate Metabolism NADH 4 TCA ATP 2 NADH X 2.5-3.3 6 (3) = 18 / 6(2.5)=15 Will varry FADH X 1.5-2 2(1.5)= 3 / 2(2)= 4 30-32 ATP/36 NOTE : Accordingly, one glucose molecule could generate a maximum of 34 ATP produced during oxidative phosphorylation plus 4 ATP(net) from substrate phosphorylation to give a total of about 38 ATP( or 36 ATP) if less efficient shuttle were functioning. ATP yield per molecule of glucose at each stage of cellular respiration. ASSIGNMENT WHYARE NUMBERS OF ATP inEXACT? Give reasons.
