REDOX REACTIONS Reduction Electrons gained H atoms added from O > C Oxygen removed Energy Stored Anabolic Simple > complex Endergonic Photosynthesis Oxidation Electrons lost H atoms lost From C to O Oxygen gained Energy released Catabolic Complex > simple Exergonic Cellular Respiration

REDOX REACTIONS ∆G = ∆H - T∆S Reduction Nonspontaneous ∆ G (+) >H, G Oxidation Spontaneous ∆ G (-) S, <G

Photosynthesis vs. Respiration Photosynthesis: 6 H 2 O + 6 CO 2 + energy C 6 H 12 O O 2 reduction oxidation Respiration: C 6 H 12 O O 2 6 H 2 O + 6 CO 2 + energy reduction oxidation

Figure 9.4 NAD + as an electron shuttle

LE 9-5a 1 / 2 O 2 H2H2 + H2OH2O Explosive release of heat and light energy Uncontrolled reaction Free energy, G

LE 9-5b 2 H e – 2 H (from food via NADH) Controlled release of energy for synthesis of ATP 2 H + 2 e – H2OH2O + 1 / 2 O 2 Cellular respiration Free energy, G Electron transport chain

LE H e – 2 H (from food via NADH) Controlled release of energy for synthesis of ATP 2 H + 2 e – H2OH2O + 1 / 2 O 2 H2H2 + H2OH2O Explosive release of heat and light energy Cellular respiration Uncontrolled reaction Free energy, G Electron transport chain

3 Types of phosphorylation: ADP  ATP Photophosphorylation - in Noncyclic Photosynthesis in ETC between PSII & PSI; using the energy of sunlight to create a high-energy electron donor and a lower-energy electron acceptor. Substrate phosphorylation -in glycolysis and Krebs cycle; Direct transfer of P i to ADP by an enzyme- A KINASE In both aerobic and anaerobic respiration – no O 2 needed Oxidative phosphorylation- at ATP synthase; result of proton gradient; electrons from NADH or FADH 2 transferred to O 2

Figure 9.6 An overview of cellular respiration (Layer 1)

Figure 9.7 Substrate-level phosphorylation

Figure 9.6 An overview of cellular respiration (Layer 2)

Figure 9.6 An overview of cellular respiration (Layer 3) Chemiosmosis

 Glycolysis Glycolysis Animation option I (simple)Glycolysis Animation Glycolysis Animation option II (intermediate)Glycolysis Animation Glycolysis Animation option III (advanced)Glycolysis Animation

LE 9-9a_1 Glucose ATP ADP Hexokinase ATP Glycolysis Oxidation phosphorylation Citric acid cycle Glucose-6-phosphate

LE 9-9a_2 Glucose ATP ADP Hexokinase ATP Glycolysis Oxidation phosphorylation Citric acid cycle Glucose-6-phosphate Phosphoglucoisomerase Phosphofructokinase Fructose-6-phosphate ATP ADP Fructose- 1, 6-bisphosphate Aldolase Isomerase Dihydroxyacetone phosphate Glyceraldehyde- 3-phosphate

LE 9-9b_1 2 NAD + Triose phosphate dehydrogenase + 2 H + NADH 2 1, 3-Bisphosphoglycerate 2 ADP 2 ATP Phosphoglycerokinase Phosphoglyceromutase 2-Phosphoglycerate 3-Phosphoglycerate

LE 9-9b_2 2 NAD + Triose phosphate dehydrogenase + 2 H + NADH 2 1, 3-Bisphosphoglycerate 2 ADP 2 ATP Phosphoglycerokinase Phosphoglyceromutase 2-Phosphoglycerate 3-Phosphoglycerate 2 ADP 2 ATP Pyruvate kinase 2 H 2 O Enolase Phosphoenolpyruvate Pyruvate

GLUCOSE C-C-C-C-C-C PGAL C-C-C PYRUVATE C-C-C PYRUVATE C-C-C AT P NAD+ NADH2 GLYCOLYSIS Prepartory Steps Energy Investment Phase Energy Payout Phase Oxidation of NAD+ Substrate level phosphorylation of ATP ANAEROBIC RESPIRATION (WITH OR WITH OUT O2) IN CYTOSOL NAD OX = NAD+ NADre = NADH NET GAIN 2 ATP 2 NADH

Coupled Reactions - A chemical reaction having a common intermediate in which energy is transfered from one side of the reaction to the other. Examples: 1. The formation of ATP is endergonic and is coupled to the creation of a proton gradient. 2. The energy of an exergonic reaction can be used to drive an endergonic reaction EX: Step 3 of glycolysis yields +3.0 kcal/mol of free energy; Step 4 has a free energy of Together = -6.0, so together they are strongly exergonic – energy is released -  passed to ATP!

END OF GLYCOLYSIS…. 2 ATP’S USED  4 ATP’S  2 net gain + 2 NAD+----  2 NADH and 2 H+ 1 GLUCOSE  2 C 3 H 4 O 3 (PYRUVIC ACID)

Prepartory Conversion Step Prior to Krebs Citric Acid Cycle

Figure 9.10 Conversion of pyruvate to acetyl CoA, the junction between glycolysis and the Krebs cycle MATRIX

NADH PYRUVATE C-C-C MITOCHONDRIAL MEMBRANE Acetyl CoA CO2 Co A MATRIX NAD+ KREB’S CITRIC ACID CYCLE

Figure 9.11 A closer look at the Krebs cycle (Layer 1) GLYCOLYSIS MOVIE Conversion Thru Krebs Summary

Figure 9.11 A closer look at the Krebs cycle (Layer 2)

Figure 9.11 A closer look at the Krebs cycle (Layer 3)

Figure 9.11 A closer look at the Krebs cycle (Layer 4)

Figure 9.12 A summary of the Krebs cycle NET GAIN PER PYRUVATE? 4 NADH 1 FADH2 1 ATP X 2 TURNS ( 1 PER PYRUVATE) 8 NADH 2 FADH2 2 ATP NET GAIN PER GLUCOSE? - so far…. 10 NADH 2 FADH2 4 ATP WHERE IS THE BIGGEST PART OF THE ENERGY NOW?

ELECTRON TRANSPORT SYSTEM

Figure 9.13 Free-energy change during electron transport

Figure 9.15 Chemiosmosis couples the electron transport chain to ATP synthesis ETS ETS w/ electrons Proton/Electron Accounting

Figure 9.14 ATP synthase, a molecular mill ATP SYNTHASE WHAT’S HAPPENING? The Details of ATP Syntase

COMPLETE CATABOLISM OF GLUCOSE REQUIRES 5 STEPS: GLYCOLYSIS-----GLUCOSE CONVERTED TO PYRUVIC ACID OXIDATION OF PYRUVIC ACID TO ACETYL CoA KREB’S CYCLE -CITRIC ACID CYCLE ELECTRON TRANSPORT CHAIN CHEMIOSMOSIS Chemiosmosis- the phosphorylation of ADP to ATP occurring when protons that are following a concentration gradient contact ATP synthase. Oxidative Phosphorylation- Refers to the coupling of the electron transport chain to ATP synthesis via the proton gradient and ATP synthase. This occurs primarily in the presence of oxygen.

From glycolysisProtons pumpedATP 2 NADH8-12*4-6* 2 ATP (substrate level phosphorylation) 2 From bridge stage 2 NADH 12 6 From citric acid cycle 6 NADH FADH ATP (substrate level phosphorylation) 2 TOTAL36-38 * The NADH that comes from glycolysis has to enter the mitochondrion in order to hand its electrons over to the electron transport system. There is usually a loss of energy involved in doing this.

Figure 9.16 Review: how each molecule of glucose yields many ATP molecules during cellular respiration

FERMENTATION

Figure 9.x2 Fermentation

Figure 9.17a Fermentation IN MOST PLANTS AND MANY MICROBES

Figure 9.17b Fermentation IN ANIMALS (MUSCLE) AND SOME MICROBES

LACTIC ACID AND ALCOHOL ARE STILL RELATIVELY HIGH IN ENERGY.... AND CAN EVENTUALLY UNDERGO AEROBIC RESPIRATION TO RELEASE THIS ENERGY AND CONVERT THEM TO CO 2 AND H 2 0. THE NET ENERGY YIELD FROM THE ANAEROBIC RESPIRATION OF ONE GLUCOSE MOLECULE IS 2 ATP MOLECULES.

Figure 9.18 Pyruvate as a key juncture in catabolism

Figure 9.19 The catabolism of various food molecules

Figure 9.20 The control of cellular respiration