Alternative Respiratory Substrates

• The respiration of lipids:

  Lipids are hydrolysed to glycerol and fatty acids. Glycerol is phosphorylated and converted into triose phosphate - It enters glycolysis.

  Fatty acids are broken down into 2 carbon fragments and converted into acetyl coenzyme A which enters Kreb’s cycle.
• The respiration of proteins:

  Proteins are hydrolysed into amino acids. These are deaminated and enter the respiratory pathway at different points depending on the number of carbon atoms they contain:

  3 carbon molecules are converted into pyruvate and enter the link reaction

  4 carbon and 5 carbon molecules are converted into intermediates in Kreb’s cycle.