Lipid and Amino Acid Metabolism

lipid transport

chylomicrons, VLDL, IDL, LDL, and HDL

cholesterol obtained

dietary sources or synthesis in liver

cholesterol biosynthesis enzyme

HMG-CoA reductase

palmitic acid

only fatty acid that humans can synthesize, produced in cytoplasm from acetyl-CoA out of mitochondria

fatty acid oxidation

occurs in mitochondria, transported by carnitine shuttle via beta oxidation

ketogenesis

ketone bodies form due to excess acetyl-CoA in the liver during starvation

ketolysis

regenerates acetyl-CoA as energy source in peripheral tissues

protein digestion

primarily in small intestines

protein catabolism

carbon skeletons of amino acids used for energy in gluconeogenesis or ketogenesis

urea cycle

amino groups enter for excretion