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Anaerobic Cellular Respiration. An aerobic . Without oxygen No oxygen to act as final electron acceptor in electron transport chain of cellular respiration. Glycolysis First. Glycolysis is first step in fermentation Breaks down the glucose molecule into 2 pyruvic acid molecules
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Anaerobic • Without oxygen • No oxygen to act as final electron acceptor in electron transport chain of cellular respiration
Glycolysis First • Glycolysis is first step in fermentation • Breaks down the glucose molecule into 2 pyruvic acid molecules • Produces 2 ATP • Takes place in cytoplasm – no need for membrane bound organelles such as mitochondria
Lactic Acid Fermentation • Carried out by human muscle cells when not enough oxygen is available – most energy is still trapped in the lactic acid molecule • Lactic acid fermentation does not produce carbon dioxide • The lactic acid molecule is later broken down in human liver cells into products (pyruvic acid) that can be fed into the Krebs cycle
Lactic Acid (continued) • Lactic acid fermentation can be carried out by certain fungi and bacteria • Used in dairy industry to produce cheese and yogurt • Can also be used in the production of acetone (nail polish remover) and methanol (methyl alcohol (poisonous))
Alcohol Fermentation • Pyruvic acid produced by glycolysis is broken down in 2 steps • 1st release carbon dioxide (important in bread rising) • 2nd step produces ethanol • Carried out by many bacteria and also by yeast (a single celled fungi)
Ethanol Formula C2OH6 Molecular formula Structural formula
Facultative Anaerobes • Organisms that use aerobic cellular respiration when there is enough oxygen but that switch to fermentation when there isn’t enough oxygen • Much more efficient use of sugar when lots of oxygen present • How would you describe human muscle cells?
The Reactions C6H12O6 2 CH3CHOHCOOH + 2 ATP Glucose lactic acid C6H12O6 → 2 C2H5OH + 2 CO2 + 2 ATP Glucose Ethanol
Yeast • Bakers yeast Saccharomycescerevisiae http://en.wikipedia.org/wiki/File:S_cerevisiae_under_DIC_microscopy.jpg