1 / 14

Chapter 9. Cellular Respiration Oxidation of Pyruvate Krebs Cycle

Chapter 9. Cellular Respiration Oxidation of Pyruvate Krebs Cycle. glucose      pyruvate. 6C. 3C. 2 x. 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

koen
Download Presentation

Chapter 9. Cellular Respiration Oxidation of Pyruvate Krebs Cycle

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 9. Cellular Respiration Oxidation of Pyruvate Krebs Cycle Adapted from: Kim Foglia

  2. glucose      pyruvate 6C 3C 2x Glycolysis is only the start • Glycolysis • Pyruvate has more energy to yield • 3 more C to strip off (to oxidize) • if O2 is available, pyruvate enters mitochondria • enzymes of Krebs cycle complete oxidation of sugar to CO2 pyruvate       CO2 3C 1C

  3. Cellular respiration

  4. What’s the point? The Point is to Make ATP! ATP Adapted from: Kim Foglia

  5. [ ] pyruvate  acetyl CoA + CO2 2x NAD NADH 1C 3C 2C Waiting to exhale? Oxidation of pyruvate • Pyruvate enters mitochondria • 3 step oxidation process • releases 1 CO2 (count the carbons!) • reduces NAD  NADH (stores energy) • produces acetyl CoA • Acetyl CoA enters Krebs cycle • where does CO2 go?

  6. Pyruvate oxidized to Acetyl CoA reduction oxidation Yield = 2C sugar + CO2 + NADH

  7. 1937 | 1953 Krebs cycle • aka Citric Acid Cycle • in mitochondrial matrix • 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 O22.7 billion years ago (photosynthesis) • eukaryotes 1.5 billion years ago (aerobic respiration (organelles) Hans Krebs 1900-1981

  8. 2C 6C 5C 4C 3C 4C 4C 4C 4C 6C CO2 CO2 Count the carbons! pyruvate acetyl CoA citrate x2 This happens twice for each glucose molecule oxidationof sugars

  9. 2C 6C 5C 4C 3C 4C 6C 4C 4C 4C NADH CO2 CO2 NADH FADH2 NADH ATP Count the electron carriers! pyruvate acetyl CoA citrate x2 This happens twice for each glucose molecule reductionof electroncarriers

  10. What’s thePoint? Whassup? So we fully oxidized glucose C6H12O6  CO2 & ended up with 4 ATP!

  11. What’s soimportant about NADH? NADH & FADH2 • Krebs cycle produces large quantities of electron carriers • NADH • FADH2 • stored energy! • go to ETC

  12. 4 NAD+1 FAD 4 NADH+1FADH2 1 ADP 1 ATP [ ] Energy accounting of Krebs cycle • Net gain = 2 ATP = 8 NADH + 2 FADH2 2x pyruvate          CO2 1C 3C 3x

  13. So why the Krebs cycle? • If the yield is only 2 ATP, then why? • value of NADH & FADH2 • electron carriers • reduced molecules store energy! • to be used in the Electron Transport Chain

  14. What’s the point? The Point is to Make ATP! ATP Adapted from: Kim Foglia

More Related