A LTERNATIVE F UELS FOR C ELLULAR R ESPIRATION Glucose is not the only fuel for respiration

P ROTEINS ( LAST RESORT ENERGY SOURCE ) Proteins can be fuel if broken down into amino acids Amino acids transformed by liver enzymes into 4 – 5 carbon acids that enter Glycolysis or Krebs Cycle. *amino group removal results in build up of nitrogenous wastes

D IAGRAM

F ATS Fats broken down into glycerol to become an intermediate of glycolysis and fatty acids that enter the Krebs cycle. Fats create twice as much ATP per gram than carbohydrates.

C ONTROL OF R ESPIRATION If energy demand is high → blood glucose broken down by glycolysis If blood glucose is low → stored glycogen broken down If energy demand is low → blood glucose is stored as glycogen and then as fat