Presentation on theme: "Metabolism and Energy Production"— Presentation transcript:
1 Metabolism and Energy Production Citric Acid CycleElectron Transport ChainATP Energy from GlucoseOxidation of Fatty AcidsMetabolic Pathways for Amino Acids
2 Citric Acid Cycle Operates under aerobic conditions only A reaction series thatOperates under aerobic conditions onlyOxidizes the 2 carbon atoms of acetyl CoA to CO2Provides reduced coenzymesO||CH3–C –CoA CO2 , FADH2, 3 NADH, + ATPacetyl CoA
4 Steps 4-5 of citric acid cycle In the next reactions, α-ketoglutarate is oxidized to succinate.α-ketoglutarate succinate
5 Steps 6-8 of citric acid cycle More oxidations convert succinate to oxaloacetate. The C=C requires FAD.
6 Coenzymes Produced in the Citric Acid Cycle 1. Acetyl CoA (2C) + oxaloacetate (4C) to citrate (6C)Citrate (6C) to α-ketoglutarate (5C) + CO23. α-ketoglutarate (5C) to succinate (4C) + CO2. GDP picks up Pi.Succinate(4C) to fumarate (C=C) to malateMalate to oxaloacetate. Start again.Total: 2CO NADH + 1 FADH2 + GTPCoenzymes1 NADH1 GTP1 FADH2
7 Learning Check Complete the following statements: When 1 acetyl CoA enters the citric acid cycle, the C atoms produce ____CO2.In 1 cycle, a total of ____NADH are produced.In 1 cycle, a total of ____FADH2 are produced.
8 Solution Complete the following statements: When 1 acetyl CoA enters the citric acid cycle, the C atoms produce 2 CO2.In 1 cycle, a total of 3 NADH are produced.In 1 cycle, a total of 1 FADH2 are produced.
9 Regulation of Citric Acid Cycle Operates when ATP is neededHigh levels of ATP and/or NADH inhibit citrate synthetase (first step in cycle)High levels of ADP and NAD+ activate isocitrate dehydrogenaseLow levels of ATP or high levels of acetyl CoA speed up the cycle to give energyATP
10 Electron Transport Chain A series of electron carriersTransfers H+ and electrons from coenzymes NADH and FADH2 (citric acid cycle)Energy released along chain to make ATPNADH + 3 ADP NAD ATPFADH2 + 2 ADP FAD ATP
11 Electron Carriers Found in three protein complexes Attached to inner membrane of mitochondriaH+ move into intermembrane space to create proton gradientAs H+ return to matrix, ATP synthase uses energy to synthesize ATPOxidation phosphorylationADP + Pi Energy ATP
12 Enzyme Complexes NADH dehydrogenase Cytochrome c reductase 3. Cytochrome c OxidaseCoenzyme ACytochrome c
13 Chemiosmotic Model Intermembrane space H+ H+ H+ H+ H+ H+ e- NADH + H FADH2 H2OMatrix ADP + P ATPCytcQ
14 Learning CheckClassify each as (1) a product of the citric acid cycle, (2) a product of the electron transport chainA. CO2B. FADH2C. NAD+D. NADHE. ATP
15 SolutionClassify each as (1) a product of the citric acid cycle, (2) a product of the electron transport chainA CO2B FADH2C NAD+D NADHE ATP
16 ATP Energy from Glycolysis (Aerobic) In the electron transport systemNADH = 3 ATPFADH2 = 2 ATPGlycolysisGlucose pyruvate + 2 ATP + 2 NADHNADH in cytoplasm FADH2 mitochondriaGlucose pyruvate + 6 ATP
17 ATP Energy from Pyruvate 2 pyruvate acetyl CoA + 2 CO NADH2 pyruvate acetyl CoA + 2 CO ATP
18 ATP Energy from Citric Acid Cycle One turn of the citric acid cycle3 NADH x 3 ATP = 9 ATP1 FADH2 x 2 ATP = 2 ATP1 GTP x 1 ATP = 1 ATPTotal = ATPGlucose provides two acetyl COA molecules for two turns of citric acid cycle2 acetyl CoA ATP + 4 CO2
19 ATP from Glucose For 1 glucose molecule undergoing complete oxidation Glycolysis ATP2 Pyruvate to 2 Acetyl CoA 6 ATP2 Acetyl CoA to 4 CO2 24 ATPGlucose O CO H2O ATP