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9.7 The Biochemistry of movement: 6. Fats release energy
| Syllabus reference (October 2002 version) | ||
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6. Fats are oxidised to release energy in cells
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Students learn to: | Students: |
Extract from Chemistry Stage 6 Syllabus (Amended
October 2002) © Board of Studies, NSW.
[Edit:27 Jun 08]
identify the importance of the oxidation of long-chain fatty acids in tissues
- Fats are a good source of energy, providing more than
twice the energy of carbohydrates on a per gram basis. They
are also the long term storage form of energy in our
bodies.
Some interesting information
Fats are less weight to carry around as they are hydrophobic, whereas stored glycogen granules contain many H-bonded water molecules which add considerable weight and limit the total amount of glycogen which can be stored.
- Most tissues in the body can use more than one energy source including oxidation of fatty acids to carbon dioxide and water for energy. This allows for the use of stored fats composed of fatty acids and glycerol as well as dietary fatty acids. Tissues can adapt to the most readily available source of energy, usually carbohydrate when food is plentiful, stored fat when food is in short supply and structural protein during starvation.
explain that the decomposition of fatty acids occurs by oxidative removal of 2-carbon fragments
identify the 2-carbon fragments as part of acetyl CoA
- Fatty acids are broken down to form acetyl-CoA as the
end product of their oxidation.
- Fatty acid oxidation occurs by successive removal of a
2C fragment, each time leaving a fatty acid with 2Cs less
in its chain. This continues until the entire chain is
broken down. Since fatty acids found naturally have even
numbers of Cs the only product will be acetyl-CoA.
- The 2C fragments end up in the acetyl part
CH3CO which is attached through a sulfur to the
rest of the Coenzyme A molecule.
- You should be able to demonstrate this process using a
specific fatty acid as an example and determine the number
of acetyl-CoA molecules obtained per fatty acid. For
example myristic acid:
CH3(CH2)nCOOH + CoA
changes to
CH3(CH2)n-2COOH + CH3CO-CoA.
process information from a simplified flow chart of biochemical pathways to identify and describe the oxidation of a typical fatty acid to acetyl CoA
- Using the Biochemical
Pathways Chart, identify and
describe the breakdown of a fatty acids
such as myristic acid to acetyl-CoA. This information could
be added to your own copy of the Biochemical Pathways
Flowchart and can be used to explain the connection between
carbohydrate oxidation and fatty acid oxidation.
- Process information from the Biochemical Pathways Flowchart to track the further breakdown path of acetyl-CoA and calculate the total amount of ATP produced per fatty acid molecule.
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