Week 9

• What is ATP?

  used by cells as a source of metabolic energy
• How much atp is stored?

  a small amount
• exchange reactions are made of two parts: oxidaton and reduction
• Oxidation: electron removal
• Redox: electron is gained (electronegativity additive)
• Metabolic Pathways 


  Clusters of chemical reactions that achieve a goal, limited to a specific part of a cell.
• Mitochondrea


  The primary site where atp production occurs
• Macronutrients overlap in metabolic pathways to produce energy as atp
• Phosphorylation: addition of a phosphate group to a compound. occurs when atp bonds are broken
• When glucose is phosphorylated it is stored as glycogen
• When glucose is transported to the liver what happens to it?

  phosphorylated for energy
• When glucose is transported to the liver what happens to it?

  released for other cells as fuel or glycogen storage OR

  converted to fatty acids and stored as triglycerides in adipose tissues (excess glucose)
• Glycolysis

  occurs in the cytosol, converts glucose to pyruvate

  anaerobic, net 2 atp
• Lipolysis

  dietary and adipocyte triglycerides are broken down, yields glycerol and 3 fatty acids
• B oxidation (fatty acid)


  metabolic reactions that oxidize free acids
• B oxidation: albumin


  fatty acids are transported to working cells in need of energy
• B oxidation : fatty acids must be activated by a coenzyme before being transported across the mitochondreal membrane by caritine
• What happens to long fatty acid chains in the mitochondrea?

  broken down into 2 carbon segments (acetyl COA)
• What is acetyl coa not able to be converte dinto?

  pyruvate, or glucose
• Proteolysis

  dietary proteins digested into small peptides or AAs
• AAs from proteolysis are transported to the liver and are mode into proteins
• Excess dietary protein is used for energy or converted into triglcerides for storage
• Energy from proteins are rarely used as fuel. proteins can be saved for metabolic functions
• When are proteins used as energy?

  used when carb intake or total energy is low
• Deamination

  amine group is removed fom the carbon skeleton and ammonia.
• Deamination is toxic, the liver converts ammonia to less toxic urea
• Glucogenic AAs

  converted to pyrvate
• Ketogenic AAs

  converted to acetyl coa
• TCA cycle (citric acid, krebs)


  loop of 8 metabolic reactions, occurs within the mitochondrea
• 2 acetyl coa are converted into 2 CO2 molecules, oxidation of NADH and FADH2 occurs,
• Ketones are byproducts of fat catabolism
• Production of energy from primarily ketones is inefficient.
• Ketosis: ketones lower blood ph
• Ketoacidosis: blood ph falls, leading to severe dehydration
• Gluconeogenesis: making of new glucose from noncarbs. usually from AAs or glycerol
• Protein catabolism: glucose production that occurs in the liver and muscle
• Lipogenesis: fat from carbs, ketogenic AAs, and alcohol.
• When excess calories are consumed, acetyl coa units form fatty acid chains. fatty acids combine with glycerol to form triglycerides
• AA synthesis makes the carbon skeleton of nonessential AAs
• Where does an amine group come from?

  transamination