KIN 3306 1nd Edition Exam 1 Study Guide Lectures 1 4 Lecture 1 January 27 Cells generate ATP through three metabolic pathways There are 3 metabolic energy systems ATP PC Glycolysis and Oxidative Phosphorylation ATP PC and Glycolysis can occur in the absence of oxygen so they are termed anaerobic metabolism On the other hand Oxidative Phosphorylation requires oxygen so is termed aerobic metabolism ATP PC System o Anaerobic metabolism o This system is a single chemical reaction that uses what we already store in our muscles PCr and ADP to create ATP PCr ADP ATP C o In this system ATP can be re created from the binding of Pi and ADP with the energy derived from the breakdown of PCr o Rate limiting enzyme creatine kinase TQ ADP and Pi activates creating kinase ATP inhibits creatine kinase o This system is used for explosive power type of activities o It is used primarily for something of short duration and will come into play anytime you start doing something o For the first few seconds this will kick it until others take over o Glycolytic System Glycolysis o Anaerobic metabolism o This system involves the breakdown of 1 glucose or 1 glycogen to 2 pyruvic acid which turns into 2 lactic acid in the presence of oxygen on the other hand pyruvate will get shuttled into the mitochondria to being the Krebs Cycle o There are two stages Energy Investment Phase and Energy Generation Phase Energy Investment Phase Uses 2 ATP Energy Generation Phase Makes 4 ATP o Net Equation for Glycolysis Glucose 2 ATP 2 Lactate H2O o Rate limiting enzyme phosphofructokinase PFK ADP and Pi activates PFK ATP inhibits PFK o This process can begin with either glucose circulating in the blood or glycogen the storage form of glucose in the muscles and liver substrate The difference between the two If it starts with glucose it will use 2 ATP to make 4 ATP with a net gain of 2 ATP If it starts with glycogen it will use 1 ATP to make 4 ATP with a net gain of 3 ATP o Oxidative System Oxidative Phosphorylation Oxidative energy production can come from carbohydrates starting from glycolysis or fats Oxidation from carbohydrates involves the 3 processes of Glycolysis the Krebs Cycle and the Electron Transport Chain o Glycolysis In carbohydrate metabolism glycolysis plays a role in both anaerobic and aerobic ATP production The only difference is the end produce In the presence of oxygen the end result of 2 pyruvic acid is converted to 2 acetyl coenzyme A o Krebs Cycle Pyruvate is converted to acetyl coenzyme A by the enzyme pyruvate dehydrogenase which turns NAD to NADH and also releases CO2 2 acetyl coenzyme A enters the mitochondria Remember that per 1 molecule of glucose we get 2 molecules of pyruvate which means that per 1 molecule of glucose we go around the Krebs Cycle twice TQ Per 1 molecule of glucose we get 6 NADH 2 FADH 2 ATP 4 CO2 Rate limiting enzyme isocitrate dehydrogenase ADP and Pi and NAD and Ca2 activates isocitrate dehydrogenase ATP and NADH inhibits isocitrate dehydrogenase o Electron Transport Chain Background info During Glycolysis H ions are released when glucose is being converted to pyruvic acid Also H ions are released when pyruvate is being converted to acetyl coenzyme A In addition to that H ions are released in several steps of the Krebs Cycle These H ions combine with NAD and FAD which then turn into NADH and FADH respectively and then these two hydrogen shuttles carry the H ions to the Electron Transport Chain The Electron Transport Chain is a group of protein complexes located in the inner mitochondrial membrane It is physically attached to the cristae of the mitochondria The Electron Transport Chain is dictated by the Chemiosmotic Theory which is when things move against their gradient The transfer of electrons along the chain provides the energy to pump protons to the outer mitochondrial compartment The pumped protons create an energy gradient which is used to resynthesize ATP from ADP and Pi For each NADH 2 5 ATP Is formed For each FADH 1 5 ATP is formed At the end of the chain the H combines with oxygen to form water which prevents acidification of the cell Because this overall process relies on oxygen as the final acceptor of electrons and H it is referred to as oxidative phosphorylation o Tally of ATP Production from Carbohydrates Fats also contribute to energy production There are 3 types of lipids fatty acids triglycerides which are the storage form and phospholipids Triglycerides are the major energy sources of the three To be used for energy triglycerides must be broken down to its basic units of one molecule of glycerol and three free fatty acid molecules The free fatty acids are the primary energy source for fat metabolism In lipid metabolism it requires more oxygen and generates more ATP than carbohydrate metabolism Also you can also store more fat than you can store carbs o Beta Oxidation Triglycerides must be catalyzed by the enzyme hormone sensitive lipase to be broken down into free fatty acids and glycerol The FFAs are released into the blood and transported to muscle cells based on the concentration gradient Before the FFA s can be used for energy production it must be converted to acetyl coenzyme A in the matrix of the mitochondria which is called beta oxidation Beta Oxidation is a series of steps in which two carbon are chopped off of the carbon chain of the FFA For example if an FFA originally has a 18 C chain Beta Oxidation will yield 9 molecules of acetyl coenzyme A This means that 9 cycles of the krebs cycle happened but only 8 cycles of beta oxidation Lecture 2 February 3 Protein Metabolism is a secondary source of fuel compared to carbohydrate and fat metabolism are the first source of fuel BCAA s are the primary source of energy in proteins Protein can go through a deamination process where when the amino acids of the protein are removed nitrogen is released Some of the nitrogen is used to form new amino acids and then some of the nitrogen cannot be oxidized by the body so it is converted to urea and then excreted by urine This conversion to urea uses ATP Protein can also go through a transamination process where an amino acid from one molecule can transfer to another group The one that lost the amine group can then be converted into various intermediates of oxidative metabolism to enter the oxidative process Glucogenesis is when amino acids are converted into glucose Ketogenesis is when amino acids can jump into different places around the krebs cycle There are