Aerobic Respiration Glycolysis Glycolysis
Animations
The
Krebs Cycle Aerobic
Respiration Animation
Anaerobic
Respiration Lactic Acid
Alcohol
Fermentation Anaerobic Respiration Summary
Biotechnology Immobilised Cells
Respiration is
the process by which cells convert food in energy.
The food from which energy is released is mainly glucose. There are 2 types
of respiration: aerobic and anaerobic respiration.
Aerobic respiration uses oxygen to get the energy from food. Living things that use aerobic
respiration are called aerobes. As a
result of aerobic respiration ATP is
released from food. The energy released is used by the cell to perform its
functions. Enzymes are used in this
process.
The basic chemical equation for respiration is:
C6H12O6
+ 6 O2
----------------> 6 CO2 + 6
H2O + ENERGY
THE STAGES OF RESPIRATION (ordinary
level)
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There are 2 stages involved in respiration:
Glycolysis takes
place in the cytosol. The cytosol is the
clear portion of the cytoplasm. Here is where the enzymes needed for stage 1 are located. This process does not need oxygen.
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The process of
glycolysis functions to split a glucose molecule into two 3-carbon molecules called pyruvic
acid (C3H4O3). This releases a small amount of ATP but most of the ATP is still
contained in the 3-Carbon molecules.
Click
here to view an interactive animation of glycolysis
Click
here to view animation #1 of glycolysis
Click
here to view animation #2 of glycolysis
Stage 2
requires oxygen and takes place in the mitochondia
of the cell.
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In stage 2 the 3-Carbon
molecules (pyruvic acid) breaks apart to form carbon dioxide and water. This releases a great deal of ATP for the cell to use.
A generalised view of respiration:
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ANAEROBIC RESPIRATION (ordinary level)
In anaerobic respiration
oxygen is not needed although it can take place in the presence of oxygen. In
anaerobic respiration glycolysis
takes place. The 3-carbon molecules (pyruvic acid) are then converted into
other products. Anaerobic respiration is also known as fermentation.
Two products of anaerobic respiration
are lactic acid and alcohol.
Lactic acid is produced in
some bacteria, fungi, and muscle tissue.
Pyruvic Acid is changed into lactic acid + small amount of energy
Pyruvic Acid is
changed to Lactic Acid +
energy (ATP)
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Examples of Lactic Acid:
Bacteria change cabbage to sauerkraut
Bacteria changing dairy products to cheese and yoghurt
Build up of lactic acid in muscles (because of lack of oxygen) causing
cramps and stiffness
ALCOHOL FERMENTATION
Alcohol fermentation occurs in
some bacteria, yeasts, and in plants deprived of oxygen. Again the pyruvic acid
formed by glycolysis is changed. Here it is changed into ethanol ethyl alcohol) and carbondioxide.
Pyruvic Acid is changed into ethanol +
small amount of energy
Pyruvic Acid is changed to Alcohol +
Carbon Dioxide + energy (ATP)
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Uses of Alcohol Fermentation
Baking:
the carbon dioxide causes the dough to rise
Beer
and Wine production
Summary of Anaerobic Respiration
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Biotechnology
Biotechnology: (See batch processing and continuous flow processing by clicking on the Bacteria Webpage on the Homepage)
Just as enzymes are immobilised for
commercial uses bacteria, fungi, and yeasts are also immobilised for production
of products. See the enzyme webpage to review
immobilisation techniques.