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Beta oxidation. Fat. Fat taken up from the blood is either stored in the intramuscular triglyceride or used immediately in mitochondria. To be able to use fat immediately in the mitochondria it needs to be broken down using beta oxidation to get in the TCA cycle. Fig 4.1 (p.60).
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Fat • Fat taken up from the blood is either stored in the intramuscular triglyceride or used immediately in mitochondria. • To be able to use fat immediately in the mitochondria it needs to be broken down using beta oxidation to get in the TCA cycle.
The fatty acids must be transported into the mitochondria for oxidation by using fatty acid transporters, converted to a fatty acyl CoA. Acyl CoA synthetase: Fatty acid + ATP + CoA Fatty acyl CoA + AMP + PPi • The transformation of fatty acyl CoA into the mitochondrial matrix occurs through three different proteins and the small molecule carnitine.
The beta oxidation begins as soon as the fatty acyl CoA appears in the matrix, using repeated cycles of four steps. • Each cycle is broken down to form a new fatty acyl CoA, shortened by two carbon atoms, plus an acetyl CoA.
Oxidative Phosporylation • Oxidative phosphorylation consists of two pathways: TCA and ETC • Acetyl CoA is the substrate for the krebs cycle which can arise form either; - breakdown of fatty acids using beta-oxidation - Pyruvate (which is produced during glygolysis in the cytosol).