Chapter 9 (continued) Fermentation

glucose 2 ATP 2 NADH 2 pyruvate 2 ATP 8 NADH 2FADH 2 O ATP water glycolysis citric Acid cycle oxidative phosphorylation

glucose 2 ATP 2 NADH 2 pyruvate 2 ATP 8 NADH 2FADH 2 O ATP water glycolysis citric Acid cycle oxidative phosphorylation What if there’s no oxygen?

glucose 2 ATP 2 NADH 2 pyruvate 2 ATP 8 NADH 2FADH 2 O ATP water glycolysis citric Acid cycle oxidative phosphorylation Then there’s nowhere for the ETC to dump its electrons.

glucose 2 ATP 2 NADH 2 pyruvate 2 ATP 8 NADH 2FADH 2 O ATP water glycolysis citric Acid cycle oxidative phosphorylation So there’s nowhere for NADH and FADH 2 to unload.

glucose 2 ATP 2 NADH 2 pyruvate 2 ATP 8 NADH 2FADH 2 O ATP water glycolysis citric Acid cycle oxidative phosphorylation So the citric acid cycle stops.

glucose 2 ATP 2 NADH 2 pyruvate glycolysis But wait! It gets even worse!

glucose 2 ATP 2 NADH 2 pyruvate 2 NAD + glycolysis You can’t make NADH without a steady supply of NAD+.

glucose 2 ATP 2 NADH 2 pyruvate 2 NAD + glycolysis NADH has nowhere to dump its electrons.

glucose 2 ATP 2 NADH 2 pyruvate 2 NAD + glycolysis So we stop making more.

glucose 2 ATP 2 NADH 2 pyruvate 2 NAD + glycolysis So even glycolysis stops.

glucose 2 ATP 2 NADH 2 pyruvate 2 NAD + glycolysis Is there no hope?

glucose 2 ATP 2 NADH 2 pyruvate 2 NAD + glycolysis There is! There’s something else we can do.

glucose 2 ATP 2 NADH 2 pyruvate 2 NAD + glycolysis We can use the NADH…

glucose 2 ATP 2 NADH 2 pyruvate 2 NAD + glycolysis 2 ethanol or 2 lactate We can use the NADH… to turn pyruvate into ethanol or lactate.

glucose 2 ATP 2 NADH 2 pyruvate 2 NAD + glycolysis 2 ethanol or 2 lactate That way, at least we get to keep the 2 ATP.

glucose 2 ATP 2 NADH 2 pyruvate 2 NAD + 2 ATP 8 NADH 2FADH 2 O ATP water glycolysis citric acid cycle oxidative phosphorylation It’s not much, but it’s better than nothing. 2 ethanol or 2 lactate.