22-1 Principles and Applications of Inorganic, Organic, and Biological Chemistry Denniston, Topping, and Caret 4th ed Chapter 22 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Power Point to Accompany

The Mitochondria Size of a bacterial cell. Outer mitochondrial membrane. Inner mitochondrial membrane: Highly folded membranes=christae Has electron transport system and ATP synthase Space between membranes is the intermembrane space. Interior is the matrix

Pyruvate to Acetyl CoA Pyruvate from glycolysis enters the mitochondria and is converted to acetyl CoA which activates the acetyl group for entry into the tricarboxylic acid cycle (Kreb’s cycle or TCA cycle). Pyruvate to acetyl CoA Decarboxylation (loss of CO 2 ) Oxidation by NAD + which accepts the hydride anion. Acetyl group linked to coenzyme A via a thioester bond.

22-4 Pyruvate Decarboxylate Complex pyruvate Acetyl CoA Vitamins Thiamine PP (B 1 ) FAD (B 2 ) NAD + (niacin) CoA (panthothenic acid) + coenzyme lipoamide

Overview: Aerobic Respiration Oxygen-requiring breakdown of food and production of ATP. Enzymes in the mitochondrial matrix. Three oxidations transfer hydride to NAD + or FAD. Electrons passed from NAD + or FAD to the electron transport chain and then O 2. Protons are transferred to the intermembrane space which leads to the synthesis of ATP as protons return to the matrix.

The Citric Acid Cycle Acetyl CoA and oxaloacetate feed the citric acid (TCA) cycle. The acetyl group is oxidized to two molecules of CO 2 and high energy electrons are transferred to NAD + and FAD. Acetyl CoA

22-7 TCA Cycle CO 2 NAD + CoA-SH CO 2 NAD + GTP Pi FAD H2OH2O Now recycle

22-8 The TCA Cycle-1, 2 Citrate synthase Citrate aconitase Isocitrate

22-9 The TCA Cycle-3, 4 Isocitrate isocitrate dehydrogenase  -ketoglutarate + CO 2 + NADH 1.Oxidation: ROH to C=O 2.Carbon dioxide released 3.NAD+ reduced + NAD + + CoA  - ketoglutarate dehydrogenase complex + CO 2 + NADH Succinyl CoA

22-10 The TCA Cycle-5, 6 + GDP + P i succinyl-CoA synthase Succinyl CoA + GTP + CoA Succinate + FAD succinate dehydrogenase Fumarate + FADH 2

22-11 The TCA Cycle-7, 8 + H 2 O fumarase L-Malate malate dehydrogenase

Control of the TCA Cycle Insert Fig 22.6 to fill below line

Oxidative Phosphorylation The respiratory electron transport system is made up of a series of electron carriers embeded in the inner mitochondrial membrane. At three sites in the electron transport system, protons (H+) can be pumped from the matrix to the intermembrane space. NADH provides three ATP molecules FADH 2 provides two ATP molecules because only two sites are involved. ATP synthesis occurs at the ATP synthase.

22-14 Insert Fig th ed I want to add comments after the Figure is in.

22-15 ATP Synthase and ATP The terminal electron acceptor in the transport chain is dioxygen. ½ O H +  H 2 O The protons in the intermembrane space flow back through ATP synthase F 0 channel activating F 1 that catalyzes phosphorylation of ADP to produce ATP.

22-16 Energy Yield from One Glucose Glycolysis Substrate-level phosphorylation2 ATP 2 NADH X 2 ATP (cytoplasm)4 ATP Two Pyruvate to two Ac-CoA 2 NADH X 3 ATP/NADH6 ATP Citric Acid Cycle (Two turns) 2 GTP X 1 ATP/GTP2 ATP 6 NADH X 3 ATP/NADH18 ATP 2 FADH 2 X 2 ATP/FADH 2 4 ATP NET36 ATP

Degradaton of Amino Acids When the body has depleted glycogen (starving), it can use amino acids for fuel. Degredation takes place in the liver in two stages. 1.Removal of the amino group. 2.Degradation of the carbon skeleton.

22-18 Degradaton of Amino Acids, cont. Removal of the a-amino group: Transamination Requires pyridoxal phosphate, a coenzyme derived from vitamin B 6.  -ketoglutarate aspartate oxaloacetate glutamate transaminase

22-19 Degradaton of Amino Acids, cont. Oxidative Deamination glutamate

22-20 Fate of Carbon Skeleton Insert Fig th and caption

the Urea Cycle Oxidative deamination produces large amounts of ammonium ion which is toxic. The pathway to eliminate ammonium ion is the Urea Cycle. Urea is excreted in the urine. Failure of enzymes in the urea cycle leads to hyperammonemia. In severe cases this leads to early death from toxic ammonium ion buildup. It can also lead to retardation, convulsions, and vomiting.

22-22 carbamoyl phosphate ornithine citruline In the mitochondria To cytosol Urea Cycle-1

22-23 arginosuccinate aspartate Urea Cycle-2 in cytosol

22-24 fumarate arginine urea! Urea Cycle-3 In cytosol

22-25 Start here

Overview of Anabolism Insert Fig 22.13

22-27 The End Aerobic Respiration And Energy Production