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AP Biology 2006-2007 Cellular Respiration Stage 2 & 3: Oxidation of Pyruvate Krebs Cycle.

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Presentation on theme: "AP Biology 2006-2007 Cellular Respiration Stage 2 & 3: Oxidation of Pyruvate Krebs Cycle."— Presentation transcript:

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2 AP Biology Cellular Respiration Stage 2 & 3: Oxidation of Pyruvate Krebs Cycle

3 AP Biology pyruvate CO 2 Glycolysis is only the start Glycolysis Pyruvate has more energy to yield 3 more C to strip off (to oxidize) if O 2 is available, pyruvate enters mitochondria enzymes of Krebs cycle complete the full oxidation of sugar to CO 2 2x2x 6C3C glucose pyruvate 3C1C

4 AP Biology Cellular respiration

5 AP Biology intermembrane space inner membrane outer membrane matrix cristae Mitochondria Structure Double membrane energy harvesting organelle smooth outer membrane highly folded inner membrane ________________ ____________________________ fluid-filled space between membranes ____________________________ inner fluid-filled space mitochondrial DNA, ribosomes enzymes free in matrix & membrane-bound mitochondrial DNA What cells would have a lot of mitochondria?

6 AP Biology Mitochondria – Function What does this tell us about the evolution of eukaryotes? __________________________ Dividing mitochondria Who else divides like that? Advantage of highly folded inner membrane?____________________________ Membrane-bound proteins Enzymes & permeases Oooooh! Form fits function!

7 AP Biology pyruvate acetyl CoA + CO 2 Oxidation of pyruvate NAD 3C2C 1C [ 2x ] Pyruvate enters mitochondrial matrix 3 step oxidation process releases _______ (count the carbons!) reduces _______________ (moves e - ) produces __________________ Acetyl CoA enters ________________ Where does the CO 2 go? Exhale!

8 AP Biology Pyruvate oxidized to Acetyl CoA Yield = 2C sugar + NADH + CO 2 reduction oxidation Coenzyme A Pyruvate Acetyl CoA C-C-C C-C CO 2 NAD + 2 x []

9 AP Biology Krebs cycle aka Citric Acid Cycle in _________________________ 8 step pathway each catalyzed by specific enzyme step-wise catabolism of 6C citrate molecule Evolved later than glycolysis does that make evolutionary sense? bacteria 3.5 billion years ago (glycolysis) free O billion years ago (photosynthesis) eukaryotes 1.5 billion years ago (aerobic respiration = organelles mitochondria) 1937 | 1953 Hans Krebs

10 AP Biology 4C6C4C 2C6C5C4C CO 2 citrate acetyl CoA Count the carbons! 3C pyruvate x2x2 oxidation of sugars This happens twice for each glucose molecule

11 AP Biology 4C6C4C 2C6C5C4C CO 2 citrate acetyl CoA Count the electron carriers! 3C pyruvate __________ __________ __________ This happens twice for each glucose molecule x2x2 CO 2 NADH FADH 2 ATP

12 AP Biology So we fully oxidized glucose C 6 H 12 O 6 CO 2 & ended up with 4 ATP! Whassup? Whats the point?

13 AP Biology Krebs cycle produces large quantities of _______________ ____________ go to Electron Transport Chain! Electron Carriers = Hydrogen Carriers Whats so important about electron carriers? H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ ATP ADP + P i

14 AP Biology Energy accounting of Krebs cycle Net gain=2 ATP =8 NADH + 2 FADH 2 1 ADP1 ATP ATP 2x 4 NAD + 1 FAD4 NADH + 1 FADH 2 pyruvate CO 2 3C 3x3x 1C

15 AP Biology Value of Krebs cycle? If the yield is only 2 ATP then how was the Krebs cycle an adaptation? __________________________________ ____________________________________ __________________________________ ____________________________________ like $$ in the bank

16 AP Biology Whats the point? The point is to make ATP ! ATP

17 AP Biology H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ And how do we do that? ATP But… Have we done that yet? ADP P + ATP synthase set up a H + gradient allow H + to flow through ATP synthase powers bonding of P i to ADP ADP + P i ATP

18 AP Biology NO! The final chapter to my story is next! Any Questions?


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