Presentation on theme: "AP Biology 2006-2007 Cellular Respiration Stage 2 & 3: Oxidation of Pyruvate Krebs Cycle."— Presentation transcript:
AP Biology Cellular Respiration Stage 2 & 3: Oxidation of Pyruvate Krebs Cycle
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
AP Biology Cellular respiration
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?
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!
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!
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 
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
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
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
AP Biology So we fully oxidized glucose C 6 H 12 O 6 CO 2 & ended up with 4 ATP! Whassup? Whats the point?
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
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
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
AP Biology Whats the point? The point is to make ATP ! ATP
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
AP Biology NO! The final chapter to my story is next! Any Questions?