1 / 12

Pathways that reduce NAD+ to NADH

Pathways that reduce NAD+ to NADH. How do cells transfer electrons from food to NAD+ to make NADH? From sugars From proteins From fatty acids. Images are from Wikimedia Commons unless otherwise indicated. Oxidation of glucose to CO 2. Glycolysis. Citric acid cycle. Pyruvate oxidation.

englishb
Download Presentation

Pathways that reduce NAD+ to NADH

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. Pathways that reduce NAD+ to NADH • How do cells transfer electrons from food to NAD+ to make NADH? • From sugars • From proteins • From fatty acids Images are from Wikimedia Commons unless otherwise indicated

  2. Oxidation of glucose to CO2 Glycolysis Citric acid cycle Pyruvate oxidation http://www.biologie.uni-hamburg.de/b-online/e19/19d.htm

  3. Glycolysis: partial oxidation of glucose to pyruvate

  4. Glycolysis – in cytoplasm of all cells • Uses 2 ATPs to “activate” glucose • Splits glucose into two 3-carbon sugars • Partially oxidizes the sugars, yielding 2 NADH per glucose • Substrate-level phosphorylation of ADP to make 4 molecules of ATP • Nets 2 pyruvates, 2 ATP, 2 NADH

  5. In respiring cells, pyruvate is oxidized to CO2 + acetyl CoA http://www.micro.siu.edu/micr201/chapter8N.html Two molecules of pyruvate are oxidized to 2 acetyl CoA + 2CO2, generating 2 NADH per molecule of glucose.

  6. Citric acid cycle generates ATP, reduced electron carriers and oxidizes acetate to CO2 Campbell & Reece Biology 8th ed.

  7. Fats and proteins http://www.ruf.rice.edu/~bioslabs/studies/mitochondria/mitokrebs.html http://www.life.umd.edu/classroom/bsci424/BSCI223WebSiteFiles/GeneralCatabolism.gif

  8. Locations of eukaryotic energy pathways Campbell & Reece Biology 8th ed.

  9. Respiring cells make most of their ATP via oxidative phosphorylation. What happens in the absence of respiration (no electron transport chain function)?

  10. Fermentation reduces pyruvate to lactic acid or ethanol, to regenerate NAD+ from NADH 2 ADP + 2 Pi 2 ATP Glucose Glycolysis 2 Pyruvate 2 NAD+ 2 NADH CO2 2 + 2 H+ 2 Acetaldehyde 2 Ethanol (a) Alcohol fermentation 2 ADP + 2 Pi 2 ATP Glucose Glycolysis 2 NADH 2 NAD+ + 2 H+ 2 Pyruvate 2 Lactate (b) Lactic acid fermentation

  11. In the absence of respiration • Cells can make ATP through glycolysis and fermentation of glucose • Cells cannot run pyruvate oxidation or citric acid cycle (no mitochondrial function in eukaryotes)

More Related