Cellular Respiration Part 2 Producing ATP by Oxidative Phosphorylation Energy from Macromolecules

Releasing Energy From Glucose Glucose (6C) 2 X Pyruvate (3C) 2 X Acetyl-CoA (2C) Cytoplasm Mitochondrion Citric Acid Cycle ATP e - Carriers Electron Transport Chain ½ O 2 H2OH2OH2OH2OATP 2 H + 4 CO 2 2 CO 2 2 CO 2 ATP Glycolysis Energy Released e-e-e-e- e-e-e-e- e-e-e-e- O 2 present

Locations of Cellular Respiration Components Matrix: Citric Acid Cycle and Pyruvate Oxidation Mitochondrion A Crista Inner Membrane: Has ATP Synthase Electron Transport Chain Intermembrane Compartment H + accumulates a b Outer Membrane

Sequence of Electron Carriers The poison cyanide prevents transfer of electrons to oxygen NADH donates electrons to Complex I ( NADH Dehydrogenase) FADH 2 donates electrons to Complex II (Succinate Dehydrogenase) Cytochromes are electron carriers with a heme prosthetic group

Formation of H + Gradient The poison arsenic prevents the buildup of the H + gradient Protons are pumped from the matrix into the intermembrane space Flow of protons through ATP synthase powers ATP production

ATP Synthase H + ions cause the rotor of ATP synthase to spin Sites in the catalytic knob are activated to catalyze ATP production The inner mitochondrial membrane is impermeable to H +, which can only pass through the ATP synthase The internal rod also spins as a result of rotor movement

Oxidative Phosphorylation Production of ATP as a result of electron transfer through carriers in the Electron Transport ChainProduction of ATP as a result of electron transfer through carriers in the Electron Transport Chain –Electrons pass through a set of membrane-associated carriers by a series of redox reactions –Energy from electron transport powers the active transport of H + to the intermembrane compartment of the mitochondrion, building a concentration gradient –Chemiosmosis: Diffusion of hydrogen ions (H + ) through the differentially permeable inner mitochondrial membrane, resulting in ATP production H + can only cross the membrane into the mitochondrial matrix through the pores of an ATP-synthesizing enzymeH + can only cross the membrane into the mitochondrial matrix through the pores of an ATP-synthesizing enzyme Movement of H + through the enzyme provides energy for ATP synthesisMovement of H + through the enzyme provides energy for ATP synthesis

Fermentation Glucose (6C) 2 X Pyruvate (3C) 2 X Acetyl-CoA (2C) Cytoplasm Mitochondrion Citric Acid Cycle ATP e - Carriers 4 CO 2 2 CO 2 2 CO 2 ATP Glycolysis oxidized e - Carriers Fermentation 2 X Lactate (3C) (in muscle) O 2 present when O 2 becomes available X O 2 absent

Alcoholic and Lactic Acid Fermentation Muscle cells Microorganisms Yeasts Some Plants Alcoholic Fermentation Lactic Acid Fermentation

Energy From Macromolecules Glucose (6C) 2 X Pyruvate (3C) 2 X Acetyl-CoA (2C) Citric Acid Cycle Glycolysis Monosaccharides Polysaccharides Disaccharides Gluconeogenesis

Energy From Macromolecules Glucose (6C) 2 X Pyruvate (3C) 2 X Acetyl-CoA (2C) Triglycerides Fatty Acids multiples of 2C Glycerol (~5%) Citric Acid Cycle Glucose (6C) 2 X Pyruvate (3C) GlycolysisGluconeogenesisDAP

Energy From Macromolecules 2 X Pyruvate (3C) 2 X Acetyl-CoA (2C) Proteins Other amino Acids 3C-amino acids Citric Acid Cycle Glucose (6C) GlycolysisGluconeogenesis

Anabolic Interconversions Glucose (6C) 2 X Pyruvate (3C) 2 X Acetyl-CoA (2C) Citric Acid Cycle GlycolysisPolysaccharidesGluconeogenesis Fatty Acids Glycerol Amino Acids Triglycerides Proteins

Regulation of Glycolysis Phosphofructokinase isPhosphofructokinase is –allosterically inhibited by ATP –allosterically activated by ADP or AMP –inhibited by citrate

Regulation of the Citric Acid Cycle Isocitrate dehydrogenaseIsocitrate dehydrogenase –responds to negative feedback from NADH and H+ and ATP –is activated by ADP and NAD+

Regulation of Acetyl-CoA Entering the Citric Acid CycleEntering the Citric Acid Cycle –Citrate synthase (1) is inhibited by ATP or NADH Use in Fatty Acid SynthesisUse in Fatty Acid Synthesis –Fatty Acid synthase (2) is stimulated by Citrate (1) (2)