Respiration

How Is a Marathoner Different from a Sprinter? Aerobic vs. anaerobic

Aerobic vs. Anaerobic Aerobic pathways Newer Require O Start in cytoplasm Completed in mitochondria Anaerobic pathways Older No O In cytoplasm

Food Sources Autotrophs (producers) Hetrotrophs (consumers) Both make ATP

CO 2 H2OH2O Glucose O2O2 ATP ECOSYSTEM Sunlight energy Photosynthesis in chloroplasts Cellular respiration in mitochondria (for cellular work) Heat energy  

Energy Consumption

Why Breathe? CO 2 O2O2 O2O2 Bloodstream Muscle cells carrying out Cellular Respiration Breathing Glucose  O 2 CO 2  H 2 O  ATP Lungs

Summary Equation for Aerobic Respiration C 6 H 12 O 6 CO 2 6H2OH2OATPs Glucose Oxygen gas Carbon dioxide 6 Water Energy O2O

Electron Transfers Oxidation - lose electron Reduction - gain electron C 6 H 12 O 6 6 O 2 6 CO 2 6 H 2 O Loss of hydrogen atoms (oxidation) Gain of hydrogen atoms (reduction) Energy (ATP)Glucose + ++

Coenzymes NAD + and FAD NADH and FADH 2 Carry electrons and hydrogen

Coenzymes O H H O2H Reduction Dehydrogenase (carries 2 electrons) NAD  2H 2H  2e  NADH HH Oxidation

ETC H2OH2O NAD  NADH ATP HH HH Controlled release of energy for synthesis of ATP Electron transport chain 2 O2O2 2e   1 2

NADH FADH 2 GLYCOLYSIS Glucose Pyruvate CITRIC ACID CYCLE OXIDATIVE PHOSPHORYLATION (Electron Transport and Chemiosmosis) Substrate-level phosphorylation Oxidative phosphorylation Mitochondrion and High-energy electrons carried by NADH ATP CO 2 Cytoplasm Substrate-level phosphorylation Figure 6.6 Overview

C 6 H 12 O 6 Glucose In-text figure Page 136

Glycolysis

Two stages Energy-requiring steps –2 ATP –Transfers P group Energy-releasing steps –Splits activated glucose –Forms 2 pyruvate, 4 ATP and 2 NADH

Glycolysis NAD  NADH HH Glucose 2 Pyruvate ATP 2 P 2 ADP

Figure 6.8_1

Figure 6.8_2

Figure 6.8_3

“Prep” Reaction Pyruvate is oxidized 2 C acetyl-CoA 3 rd C released as CO 2 NAD + -> NADH

“Prep” Reaction CO 2 Pyruvate NAD  NADH  H  CoA Acetyl CoA (acetyl coenzyme A) Coenzyme A Figure 6.8

Citric Acid Cycle CoA CO 2 NAD  NADH FAD FADH 2 ATPP CITRIC ACID CYCLE ADP  3 3  3 H  Acetyl CoA 2

Citric Acid Cycle Loads e- and H onto NAD+ and FAD ATP by substrate-level Phos.

1 turn yields: –2 CO 2 –1 ATP, –3 NADH –1 FADH 2 –Regenerates starting product Citric Acid Cycle and Stepsand CITRIC ACID CYCLE Oxaloacetate CoA 2 carbons enter cycle Acetyl CoA Citrate leaves cycle  H H NAD  NADH CO 2 Alpha-ketoglutarate leaves cycleCO 2 ADP P NAD  NADH  H  ATP  Succinate FAD FADH 2 Malate  H  NAD  NADH Step Acetyl CoA stokes the furnace. Steps NADH, ATP, and CO 2 are generated during redox reactions. Redox reactions generate FADH 2 and NADH.

Electron Transport Coenzymes deliver electrons Pump H + Forms H + gradient H + flows down gradient Powers ATP formation (ATP synthase)

Figure 6.12a

Importance of Oxygen Intermembrane space Inner mitochondrial membrane Mitochondrial matrix Protein complex Electron flow Electron carrier NADH NAD + FADH 2 FAD H2OH2O ATP ADP ATP synthase H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+  P O2O2 Electron Transport Chain Chemiosmosis. OXIDATIVE PHOSPHORYLATION Figure 6.10

Summary of Energy Harvest (per molecule of glucose) Glycolysis –2 ATP Citric acid and “prep” rxns –2 ATP ETC –32 ATP formed

686 kcal of energy are released 7.5 kcal are conserved in each ATP When 36 ATP form, 270 kcal (36 X 7.5) are captured in ATP Efficiency is 270 / 686 X 100 = 39 percent Most energy is lost as heat FYI - Efficiency of Aerobic Respiration

Poisons Block the movement of electrons (cyanide, CO) Block the flow of H + through ATP synthase (Oligomycin) H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ O2O2 H2OH2O P ATP NADHNAD + FADH 2 FAD Rotenone Cyanide, carbon monoxide Oligomycin DNP ATP Synthase  2 ADP  Electron Transport Chain Chemiosmosis 1 2 Figure 6.11

Anaerobic Pathways Less ATP Fermentation pathways

Fermentation Pathways Bacteria –Lactobacillus (cheese) Animal cells

Fermentation Pathways Glycolysis 2 ATP Regenerate NAD +

Lactate Fermentation Muscle cells FAST ATP Lactic acid builds up 2 Lactate NAD  NADH NAD  ATP 2 ADP  2 2 Pyruvate GLYCOLYSIS P Glucose

Alcoholic Fermentation Produces ethanol Yeast NAD  NADH NAD  GLYCOLYSIS 2 ADP  2 P ATP Glucose 2 Pyruvate released CO 2 2 Ethanol 2 2 Figure 6.13B

Figure 6.16

Question of the Day How does the insecticide rotenone work? Is it safe?