Part 2 of Module 3 - Products Involved

Module 3 3). Glycolysis Glycolysis happens in the cytosol of cells which is the sarcoplasm of a muscle cell. Products involved in Bioenergetics Both pyruvate (1) and lactate are the products of glycolysis. 2 molecules of a product of glycolysis: pyruvate, 2 lactate, or 1 of each NADH (a reducing equivalent that travels to the ETC), ADP, and ATP as products for glycolysis. The substrates for glycolysis: ATP, ADP, NAD, with glucose being most important. 4). Krebs cycle and electron transport chain These two pathways are found in the mitochondria. Pathways and enzymes represent the oxidative system. Glycolytic pyruvate is transported into a mitochondrion where it is converted to acetyl-CoA via the PDH enzyme. Acetyl-CoA produced by PDH becomes a main substrate for the Krebs cycle. As long as acetyl-CoA is produced, molecules keep feeding themselves. Substrates of the ETC are the reducing equivalents: NADH and FADH2. The ETC utilizes both electrons and H+ from the reducing equivalents. The final electron acceptor (O2) bonds with 2H+ to form H2O. Electrons carried in NADH: Pyruvic acid Electrons carried in NADH and FADH2: Glucose Glycolysis Cytoplasm Krebs Cycle Mitochondrion Electron Transport Chain Mitochondrion ATP Cytoplasm ATP Mitochondrion ATP Mitochondrion 5). Gluconeogenesis Takes place in the liver. Creates new glucose: The pathway, via many enzymes, that converts different substrates to glucose. Lipolysis: The catabolism (breakdown) of triglycerides into fatty acids & glycerol. Proteolysis: Catabolism of proteins into amino acids. Module 3 Glycogenolysis: The breakdown of glycogen into glucose Glycolysis: breakdown of glucose (from glycogen or blood glucose) to pyruvate / lactate ALL OF THE ABOVE ARE SUBSTRATES OF GLUCONEOGENESIS Which of the following molecules can help supply glucose to a working muscle? Lactate, pyruvate, glycerol, Alanine (amino acids) What do you think happens to the rate at which we use gluconeogenesis when exercise is intense? Gluconeogenesis increases What do you think happens to our use of gluconeogenesis during rest? Gluconeogenesis decreases 6). Beta oxidation Occurs within the mitochondria. Converting fatty acids (that have been transported into the mitochondria) into Acetyl-CoA. Acetyl-CoA can then proceed through the Krebs cycle What is the substrate for beta oxidation? Fatty acids What are the sources of Acetyl-CoA that will enter the Krebs cycle? Glycolysis produces pyruvate (from glucose) which is transported into mitochondria & converted to Acetyl CoA by PDH and fed into the Krebs cycle (FAST) Acetyl CoA can be made from fat and CHO sources? TRUE 7). Cori cycle What is the intensity at which the production of lactate and the use of lactate as a substrate for gluconeogenesis? High intensity What are all the reasons that can cause lactate to be made? Glycolysis is making a lot of pyruvate There is not enough mitochondria to take up the pyruvate being produced in the sarcoplasm PDH and the mitochondria can't keep up with the amount of pyruvate being made The more mitochondria you have, the longer it takes for lactate to build up (Lactate threshold) UNDER HIGH INTENSITY CONDITIONS: Too much pyruvate is being produced and there isn't enough mitochondria to use all of the pyruvate being produced by glycolysis. The mitochondria become overwhelmed by the amount of pyruvate being produced by glycolysis & can't handle it all. If pyruvate isn't taken up into the mitochondria the liver is converted to lactate.