Chapter 9 (continued) Fermentation. glucose 2 ATP 2 NADH 2 pyruvate 2 ATP 8 NADH 2FADH 2 O 2 32-34...

Chapter 9 (continued)

Fermentation

glucose

2 ATP

2 NADH

2 pyruvate

2 ATP

8 NADH

2FADH2

O2 32-34 ATP

water

glycolysis

citric Acidcycle

oxidative phosphorylation

glucose

2 ATP

2 NADH

2 pyruvate

2 ATP

8 NADH

2FADH2

O2 32-34 ATP

water

glycolysis

citric Acidcycle

oxidative phosphorylation

What if there’s no oxygen?

glucose

2 ATP

2 NADH

2 pyruvate

2 ATP

8 NADH

2FADH2

O2 32-34 ATP

water

glycolysis

citric Acidcycle

oxidative phosphorylation

Then there’s nowhere for the ETC to dump its electrons.

glucose

2 ATP

2 NADH

2 pyruvate

2 ATP

8 NADH

2FADH2

O2 32-34 ATP

water

glycolysis

citric Acidcycle

oxidative phosphorylation

So there’s nowhere for NADH

and FADH2 to unload.

glucose

2 ATP

2 NADH

2 pyruvate

2 ATP

8 NADH

2FADH2

O2 32-34 ATP

water

glycolysis

citric Acidcycle

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 lactateWe can use the NADH… to turn

pyruvateinto 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

2FADH2

O2 32-34 ATP

water

glycolysis

citric acidcycle

oxidative phosphorylationIt’s not much, but it’s

better than nothing.

2 ethanol or 2 lactate

.