These are water soluble molecules that are by-products of fat metabolism. Can potentially release more atp than glucose and are an important fuel source for the brain and heart under some specific conditions, in the absence of cho. Then keto(cid:374)e (cid:271)odes are released i(cid:374)to the (cid:271)lood strea(cid:373) (cid:449)here it tra(cid:448)els to peripheral tissue. This is what happens when we restrict cho intake. During the krebs cycle, less oxaloacetate is formed but we still get an increase in acetyl-coa. This acetyl- coa goes to form ketone bodies. Acetyl coa + acetyl coa = ketone body. Occurs in the liver: muscle, renal cortex, brain during prolonged fast, heart. Note: wo(cid:374)"t (cid:271)e used (cid:271)(cid:455) the li(cid:448)er, the(cid:455) do(cid:374)"t have the appropriate enzyme to convert it to energy, but it can create energy from ffas and glucose via gluconeogenesis. Ketosis: accumulation of ketone bodies in blood, metabolic state where an individual achieves and sustains a conc. of blood ketones of 0. 5-8 (cid:373)(cid:373)ol/l.