Lab 6 Respiration: Aerobic & Anaerobic Oxidation of Organic

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Respiration Aerobic Anaerobic Oxidation of
Organic
Lab 6

• Exp.12

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Metabolism(Enzymes mediated reaction of living
cells)

• - Anabolism Vs. Catabolism.

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Cellular Respiration

• organic molecules (energy rich ) must be broken
  down and their energy is transferred to ATP .
• This break down involves a step by step reaction
  called Glycolysis where
• Glucose ? 2 molecules of pyruvic acid

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Glycolysis

• 2 NAD are reduced to NADH.
• NAD amount is limited in cells

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NOW, the presence or absence of O2 makes a
difference
The fate of pyruvate depends on oxygen
availability
- O2
O2
Aerobic respiration
Fermentation
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2
2
2 Citric acid
4 CO2 2ATP 6NADH 2FADH2
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Electron Transport

• O2 2 NADH 2 H ? 2 H2 O 2 NAD
• And we are left with the 2 pyruvic acid molecules
  that can break further to generate more ATP.

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2
2
2 Citric acid
4 CO2 2ATP 6NADH 2FADH2
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If O2 is absent Fermentation

• Pyruvic acid will accept the electrons from NADH
  and will give the cell back its NAD.
• Two types
• 1- Lactic acid fermentation
• 2- Alcoholic fermentation

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Lactic acid fermentation(in animals some
microbes)

• C6H12O6 2 Pyruvic acid 2 NADH2H
• 2 lactic acid 2 NAD
• Fatigue

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Alcoholic fermentation(in plants some microbes)

• C6H12O6 2 Pyruvic acid 2 NADH 2 H
• 2 C2 H5 OH 2 CO2 2 NAD
• (ethanol)

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Experiment

• Fermentation by yeast
• alcoholic beverages, cheeses, yogurt and other
  dairy products.
• Saccharomyces cerevisiae ( bakers or brewers
  yeast ) used in bread making

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Fermentation tube
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Use a dye as an indicator of electron transport
in yeast.

• Methylene blue will be the final electron
  acceptor.
• In the absence of oxygen, methylene blue will
  accept the electrons Hydrogen ions that follow
  them.
• Oxidized Form Reduced Form
• (blue)
  (colorless)

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B- Add the following 1- Magnesium Chloride
2- Iodoacetamide 3- Citrate 4- Citrate
Iodoacetamide. 5- Formaldehyde. 6- distilled
water.
A- Add yeast suspension (1cm) to 6 test tubes
Methylene Blue
E- Wait for 15 mins record change in color
C- Add one drop to all the tubes
D- Mix all the tubes
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CO2 production by respiring plants

• Ba(OH)2 CO2 BaCO3
• 
  (Barium
  carbonate)
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  White precipitae