Overview of Cellular Respiration Copy the Slides with the Smiley Face

ATP Supplies Energy for Cellular Function What activities require ATP? Where does this energy come from? –Food and O 2 are needed to make ATP. How does it work?

Figure 9.1

The big picture Photosynthesis light 6 CO H > C 6 H 12 O H 2 0+6O 2 Cellular Respiration C 6 H 12 O H 2 0+6O > 6 CO H 2 0 +energy

The big picture Photosynthesis 6 CO H20 ---> C6H12O6 + 6 H20+6O2 Cellular Respiration C6H12O6 + 6 H20+6O > 6 CO H20

Figure 9.2 Light energy ECOSYSTEM Photosynthesis in chloroplasts Cellular respiration in mitochondria CO 2  H 2 O  O 2 Organic molecules ATP powers most cellular work ATP Heat energy

Catabolic Pathways and Production of ATP The breakdown of organic molecules is exergonic Fermentation is a partial degradation of sugars that occurs without O 2 Aerobic respiration consumes organic molecules and O 2 and yields ATP Anaerobic respiration is similar to aerobic respiration but consumes compounds other than O 2 © 2011 Pearson Education, Inc.

Energy Procurement Chemical bonds are broken in small steps that maximize the energy that is made available to the cell from food. Energetic Electrons are not haphazardly thrown throughout the cell...

NADH and FADH 2 ARE ELECTRON SHUTTLES NAD is reduced to NADH, FAD is reduced to FADH 2 These high energy e - s are carried to inner mitochondrial membrane to make ATP. Electron cascade-- e - s then pass down a complex of carriers on a membrane, releasing packets of energy in small increments. We talked about enzyme complexes (ch 8), this uses several. (see page 175, electron transport chain, ETC)

Figure 9.5 (a) Uncontrolled reaction (b) Cellular respiration Explosive release of heat and light energy Controlled release of energy for synthesis of ATP Free energy, G H 2  1 / 2 O 2 2 H  1 / 2 O 2 H2OH2O H2OH2O 2 H +  2 e  2 e  2 H + ATP Electron transport chain (from food via NADH)

Stepwise Energy Harvest via NAD + and the Electron Transport Chain In cellular respiration, glucose and other organic molecules are broken down in a series of steps Electrons from organic compounds are usually first transferred to NAD +, a coenzyme As an electron acceptor, NAD + functions as an oxidizing agent during cellular respiration Each NADH (the reduced form of NAD + ) represents stored energy that is tapped to synthesize ATP © 2011 Pearson Education, Inc.

Figure 9.4 Nicotinamide (oxidized form) NAD  (from food) Dehydrogenase Reduction of NAD  Oxidation of NADH Nicotinamide (reduced form) NADH This is NAD+ Does this remind you of anything?

Oxidation of Organic Fuel Molecules During Cellular Respiration During cellular respiration, the fuel (such as glucose) is oxidized, and O 2 is reduced © 2011 Pearson Education, Inc.

The Principle of Redox Chemical reactions that transfer electrons between reactants are called oxidation-reduction reactions, or redox reactions In oxidation, a substance loses electrons, or is oxidized In reduction, a substance gains electrons, or is reduced (the amount of positive charge is reduced) © 2011 Pearson Education, Inc.

2 ways to make ATP Oxidative Phosphorylation-Proton gradient across membrane stores potential energy. –This occurs alongside ETC –- Chemiosmosis-Protons pass thru ATP synthase to make ATP Substrate level phosphorylation –Simpler, not membrane bound –Phosphate transferred from a substrate to ADP, forms ATP –GYCOLYSIS AND KREB’S

Aerobic Respiration occurs in four stages 1)Glycolysis- 1)Glucose to pyruvate, in cytoplasm 2)Pyruvate Oxidation 1)Pyruvate ---> Acetyl CoA, in Mitochondrial Intermembrane Space 3)Citric Acid Cycle ( same as Kreb’s Cycle ) 1)Acetyl CoA---> CO 2, ATP, NADH, FADH 2 in Mitochondrial Matrix 4)Electron Transport Chain 1)NADH, FADH > High Levels of ATP and water Inner mitochondrial membrane

Figure Electrons carried via NADH Electrons carried via NADH and FADH 2 Citric acid cycle Pyruvate oxidation Acetyl CoA Glycolysis Glucose Pyruvate Oxidative phosphorylation: electron transport and chemiosmosis CYTOSOL MITOCHONDRION ATP Substrate-level phosphorylation Oxidative phosphorylation Where processes take place:

Figure Glycolysis: Energy Investment Phase ATP Glucose Glucose 6-phosphate Fructose 6-phosphate Fructose 1,6-bisphosphate Dihydroxyacetone phosphate Glyceraldehyde 3-phosphate To step 6 ADP Hexokinase Phosphogluco- isomerase Phospho- fructokinase Aldolase Isomerase 12345

Figure Glycolysis: Energy Payoff Phase 2 ATP 2 NADH 2 NAD  + 2 H  2 P i 2 ADP 1,3-Bisphospho- glycerate 3-Phospho- glycerate 2-Phospho- glycerate Phosphoenol- pyruvate (PEP) Pyruvate 2 ADP H 2 O Phospho- glycerokinase Phospho- glyceromutase EnolasePyruvate kinase Triose phosphate dehydrogenase

Figure NADH 1 Acetyl CoA Citrate Isocitrate  -Ketoglutarate Succinyl CoA Succinate Fumarate Malate Citric acid cycle NAD  NADH FADH 2 ATP + H  NAD  H2OH2O H2OH2O ADP GTPGDP P i FAD CoA-SH CO2CO2 CO2CO2 Oxaloacetate Citric Acid Cycle (Kreb’s Cycle)

Figure 9.14 INTERMEMBRANE SPACE Rotor Stator HH Internal rod Catalytic knob ADP + P i ATP MITOCHONDRIAL MATRIX What are we looking at? ____________ _

Figure 9.15 Protein complex of electron carriers (carrying electrons from food) Electron transport chain Oxidative phosphorylation Chemiosmosis ATP synth- ase I II III IV Q Cyt c FAD FADH 2 NADH ADP  P i NAD  HH 2 H  + 1 / 2 O 2 HH HH HH 21 HH H2OH2O ATP

Figure 9.19 Carbohydrates Proteins Fatty acids Amino acids Sugars Fats Glycerol Glycolysis Glucose Glyceraldehyde 3- P NH 3 Pyruvate Acetyl CoA Citric acid cycle Oxidative phosphorylation

Figure 9.20 Phosphofructokinase Glucose Glycolysis AMP Stimulates    Fructose 6-phosphate Fructose 1,6-bisphosphate Pyruvate Inhibits ATPCitrate Citric acid cycle Oxidative phosphorylation Acetyl CoA NEGATIVE FEEDBACK EXAMPLE

Anaerobic Respiration ATP is made in glycolysis only NADH needs to be recycled Ethanol (Alcohol) fermentation –Acetaldehyde intermediate – CO 2, ATP and ethanol are products. How do products benefit humans? Lactic Acid fermentation –Only lactate and ATP produced. What is the benefit to humans?

Anaerobic Respiration See animation

Remember: Protein Kinase A protein kinase or kinase is an enzyme that adds a phosphate group from ATP to a target protein. HARVARD MITOCHONDRIA ANIMATIONHARVARD MITOCHONDRIA ANIMATION

Effect of poisons and toxins Cyanide- competive inhibitor of cytochrome C oxidase. Blocks ATP production. Rotenone (rat poison and insecticide)- competive inhibitor of NADH producing enzyme, which inhibits ATP production Carbon monoxide (CO) – binds with Hb 300 X more efficiently than O 2. No oxygen, no final electron acceptor

What you will be tested on in Respiration These notes Major Products and Reactants of each stage Meaning what goes in, and what comes out. You need to know number of ATP derived from each stage. Fill in the blank items on handouts.