metabolism 2

• fatty acids are broken down into 2 carbon units by beta oxidation in the matrix
• beta oxidation reduces NAD and FAD, and produces ATP
• end result of Beta oxidation is multiple units of acetyl CoA for Krebs cycle
• lipids can produce so much energy as they reduce many coenzymes for ETC
• in beta oxidation, the 2 carbons break away (form acetyl group) for Krebs and the 2 NADH and FADH go to ETC
• in triglycerides, the fatty acids are cleaved for beta oxidation
• the glycerol from triglycerides goes into the cytosol and becomes glyceraldehyde phosphate, to go into glycolysis
• lipolysis produces many ATP as beta oxidation produces many co-enzymes
• lipid synthesis: anabolism
• anabolism requires ATP
• anabolism is the formation of glyceraldehyde 3 phosphate back into glycerol for the back bone of triglycerides, that are built back from acetyl CoA
• proteins are the only macronutrients that contains nitrogen, so it needs to be removed, this is excreted with 2 hydrogens in the urea
• the R group in the keto acid determines how the amino acid is metabolised and its entry into the metabolism pathway
• glycogen synthesis in the liver: insulin is released by pancreas due to increased BG, and stimulates liver cell to produce glycogen (Glycogenesis), which requires ATP
• liver glycogen degradation: glucagon is released from pancreas and signals the liver to break down glycogen and release into blood (glycogenolysis), liver can do this as it has glucose 6 phosphatase
• glycogen degradation can only happen in the liver
• muscle glycogen synthesis: insulin must be present as stimulates Glut 4 to cell membrane to allow glucose to enter the cell
• insulin signals skeletal muscle to produce glycogen
• skeletal muscle doesnt have glucose 6 phosphatase so it cannot produce glucose from glucose 6 phosphate, instead the G-6-P enters glycolysis
• over 100 ATP is produced for each fatty acid over 16c long
• glucose 6 phosphatase is in liver, some kidney cells, and some intestinal cells