AP Biology 2006-2007

Anaerobic RespirationStages:

1. Glycolysis2. Fermentation

yeast

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Anaerobic Respiration

Cellular Respiration (harvesting ATP from glucose) in the absence of Oxygen.

1. Bacteria that live in oxygen-free places

2. Some organisms that are exposed to oxygen, but switch to fermentation when oxygen is scarce.

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Convert: glucose (6C) to 2 pyruvate (3C)

produces: 4 ATP & 2 NADH

uses:2 ATP

net yield: 2 ATP & 2 NADH

Glycolysis

ATP2

2

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Pyruvate is a branching pointPyruvate

O2O2

mitochondriaKrebs cycle

aerobic respiration

fermentationanaerobicrespiration

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FERMENTATION

Fermentation does not yield any more ATP than the tiny amount supplied by Glycolysis

It simply regenerates NAD, to refuel Glycolysis.

1. This is plenty of ATP for small anaerobic organisms

2. Not enough for large, multi-celled organisms

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Lactate Fermentation

-Occurs in some bacteria AND animals for a quick fix of ATP

-Regenerates 2 NAD

-Produces 2 Lactates

(Lactic Acids)

pyruvate lactic acid3C 3C

NADH NAD+ back to glycolysis

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Alcoholic Fermentation

-Occurs in bacteria, some plants, AND

some fungi (like yeast) for a quick fix of ATP

-Regenerates 2 NAD

-Produces 2 Ethanol (Alcohol) and

2 Carbon Dioxides

1C3C 2Cpyruvate ethanol + CO2

NADH NAD+ back to glycolysis