3. **Glucose made as a byproduct of photosynthetic reactions Harvesting stored energy…  Energy stored in organic molecules  carbohydrates, fats, proteins  Heterotrophs eat food  digestive results… raw materials for synthesis fuels for energy controlled release of energy “burning” fuels occurs in series of step-by-step enzyme-controlled reactions

4.  Glucose is the treasure chest  catabolize glucose to produce ATP C 6 H 12 O 6 6O 2 ATP 6H 2 O 6CO 2  + ++ RESPIRATION = making ATP (& some heat) by burning fuels in many small steps CO 2 + H 2 O + ATP (+ heat) ATP glucose glucose + oxygen  energy + water + carbon dioxide respiration O2O2 + heat enzymes ATP

5.  Food digestion = bond breaking & electron movement (energy carrying)  Electron movement  NOT alone → move as part of H atom p e + H + H +– loses e-gains e-oxidizedreduced oxidationreduction C 6 H 12 O 6 6O 2 6CO 2 6H 2 O ATP  +++ oxidation reduction H e-e-

6.  Electron carriers move ele - by shuttling H atoms  NAD +  NADH (reduced)  FAD +2  FADH 2 (reduced) + H reduction oxidation P O–O– O–O– O –O–O P O–O– O–O– O –O–O C C O NH 2 N+N+ H adenine ribose sugar phosphates NAD + nicotinamide Vitamin B3 niacin P O–O– O–O– O –O–O P O–O– O–O– O –O–O C C O NH 2 N+N+ H NADH carries electrons as a reduced molecule reducing power! H Ele - Movement in Respiration

7.  4 metabolic stages  Anaerobic respiration (NO O 2 ) 1. Glycolysis in cytosol  Aerobic respiration ( O 2 ) in mitochondria 2. Pyruvate oxidation 3. Krebs cycle 4. Electron transport chain C 6 H 12 O 6 6O 2 ATP 6H 2 O 6CO 2  +++ (+ heat )

8. That’s not enough ATP for me!  “glyco – lysis” (splitting sugar)  Pathway observed in nearly ALL organisms Speculated as one of oldest pathways, most fundamental WHY?  Inefficient For every 1 glucose generate only 2 ATP glucose      pyruvate 2x2x 6C3C

9. 10 reactions  convert glucose (6C) to 2 pyruvate (3C)  produce: 4 ATP & 2 NADH  consumes: 2 ATP  NET YIELD: 2 ATP & 2 NADH glucose C-C-C-C-C-C fructose-1,6bP P-C-C-C-C-C-C-P G3P x2 C-C-C-P Pyruvate x2 C-C-C G3P = glyceraldehyde-3-phosphate ATP 2 ADP 2 ATP 4 ADP 4 NAD + 2 2Pi2Pi enzyme 2Pi2Pi 2H2H 2 G3P x2 P~C-C-C-P

10. WWhy use excess when its not needed? [[ATP] activates/inactivates phosphofructokinase EEnzyme used to make 1,6 fructose bisphosphate AAllosteric regulation!!! 22 active sites 1. forms 1,6 fructose bisphosphate 2. conformation change, inactivate

11.  Not a lot of energy…  for 1 billon years + life on Earth survived this way no O 2 = slow growth, slow reproduction only harvest 3.5% of energy stored in glucose more carbons to strip off = more energy to harvest O2O2 O2O2 O2O2 O2O2 O2O2 Is this enough to support life? O 2 present Onto the Krebs Cycle!!!

13. intermembrane space inner membrane outer membrane matrix cristae  Double membrane  smooth outer membrane  highly folded inner membrane cristae  intermembrane space fluid-filled between membranes  matrix inner fluid-filled space  DNA, ribosomes  enzymes free in matrix & membrane-bound mitochondrial DNA

14. Yield = 2C sugar + NADH + CO 2 reduction oxidation Coenzyme A Pyruvate Acetyl CoA C-C-C C-C CO 2 NAD + 2 x [ ] Prepping for Krebs: formation of Acetyl CoA

15. pyruvate    acetyl CoA + CO 2 NAD 3C2C 1C [ 2x ]  Pyruvate enters matrix  3 step oxidation process  releases 2 CO 2  reduces 2 NAD +  2 NADH (moves e - )  produces 2 acetyl CoA  enters Krebs cycle Electron Carriers = Hydrogen Carriers

16.  aka Citric Acid Cycle  in mitochondrial matrix  8 step pathway each catalyzed by specific enzyme step-wise catabolism of 6C citrate molecule (stripping out the carbons)  Appeared later than glycolysis – WHY? 1937 | 1953 Hans Krebs 1900-1981

17. 4C6C4C 2C6C5C4C CO 2 citrate acetyl CoA Count the carbons! 3C pyruvate x2x2 oxidation of sugars This happens twice for each glucose molecule **Process regulated by + and – feedback control by [ATP]!!!**

18. 4C6C4C 2C6C5C4C CO 2 citrate acetyl CoA Count the electron carriers! 3C pyruvate reduction of electron carriers This happens twice for each glucose molecule x2x2 NADH FADH 2 ATP

19. Fully oxidized C 6 H 12 O 6  CO 2 NET YIELD: (4 NADH) x 2 (1 ATP) x 2 (1 FADH 2 ) x 2 8 NADH 2 ATP 2 FADH2 How’s our savings?

20.  Glycolysis  2 ATP  Kreb’s cycle  2 ATP  Life takes a lot of energy to run, need to extract more energy than 4 ATP!  Fun Fact!!! A working muscle recycles over 10 million ATPs per second I need a lot more ATP!

21.  Proteins built into inner mitochondrial membrane along cristae transport proteins & enzymes  In presence of O 2  Ele - shuttled (by NADH & FADH 2 )down ETC pump H + to create H + gradient → chemiosmosis!!!  yields ~36 ATP from 1 glucose!

22. Intermembrane space Mitochondrial matrix Q C NADH dehydrogenase cytochrome bc complex cytochrome c oxidase complex Inner mitochondrial membrane

23. intermembrane space mitochondrial matrix inner mitochondrial membrane NAD + Q C NADH H 2 O H+H+ e–e– 2H + +O2O2 H+H+ H+H+ e–e– FADH 2 1212 NADH dehydrogenase cytochrome bc complex cytochrome c oxidase complex FAD e–e– H H  e- + H + NADH  NAD + + H H p e Building proton gradient! What powers the proton (H + ) pumps?… Let’s Follow the Chain…

24.  Ele - move in steps from carrier to carrier downhill to oxygen  each carrier more electronegative  controlled oxidation  controlled release of energy Electrons Flow Downhill

25. H+H+ ADP + P i H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+  Set up H + gradient  Allow protons to flow through ATP synthase  Synthesize ATP ADP + P i  ATP CHEMIOSMOSIS!!!

26. Energy Conversion **The Rules: NADH = 3 ATP FADH 2 = 2 ATP GGlycolysis – 2 NADH CConversion to – 2 NADH Acetyl CoA KKrebs cycle - 6 NADH 2 FADH 2 EETC 6 ATP 18 ATP + 4 ATP = 22 ATP 34 ATP!!!

27. 2 ATP ~34 ATP ++ ~40 ATP

29. amino group = Waste, excreted as ammonia, urea, or uric acid N H H C—OH || O H | —C— | R waste glycolysis Krebs cycle proteins      amino acids hydrolysis 2C sugar = carbon skeleton = enters glycolysis or Krebs cycle

30. fatty acids  2C acetyl  acetyl  Krebs groupscoAcycle 3C glycerol enters glycolysis as G3P enter Krebs cycle as acetyl CoA 2C fatty acids fats      glycerol + fatty acids hydrolysis glycerol (3C)   G3P   glycolysis

31.  Digestion  carbohydrates, fats & proteins all catabolized through same pathways enter at different points  cell extracts energy from every source

32. Why waste? Enough energy? Build stuff!!!  points in glycolysis & Krebs cycle used as link to pathways for synthesis run pathways “backwards” have extra fuel, build fat! Krebs cycle intermediaries    amino acids pyruvate   glucose acetyl CoA   fatty acids

33. What happens the absence of oxygen? Pyruvate O2O2 O2O2 aerobic respiration mitochondria Krebs cycle anaerobic respiration fermentation

34. Dead end process  ~12% ethanol, kills cells  can’t reverse reaction Alcohol Fermentation

35. Reversible process  if O 2 becomes available, lactate converted to pyruvate by the liver Lactic Acid Fermentation

36. recycle NADH

37.  Bacteria, yeast  Animals, some fungi 1C 3C2C pyruvate  ethanol + CO 2 pyruvate  lactic acid 3C  beer, wine, bread  cheese, anaerobic exercise (no O 2 ) NADH NAD + NADH NAD + back to glycolysis  Commercial Uses…

38.  ETC ETC  ATP Synthase ATP Synthase