CHAPTER 13 CONT. LECTURE NOTESMitochondrial Compartments-All anaerobic elimination of pyruvate happens in the cytoplasm-If it happens in aerobic conditions, pyruvate moves into the mitochondria-Outer membrane-Porins: -Have huge space for solutes to move through-Not very selective in terms of what they allow to pass through, as long as it fits-Inner membrane-Is a barrier-Need specific membrane transport proteins to get solutes into the lumen of the mitochondria-Lumen is called the matrix-Matrix is where pyruvate dehydrogenase is; 1st complex of enzymes that deals with pyruvate-Where electron transport happens-ATP is synthesized here-The intermembrane space is important because one of the ways that the energy from electrons is used is to transport protons from the matrix into the intermembrane space-The difference between the concentration of the protons, difference in pH, means there is a charge difference across the membrane (pH difference is the same as a charge difference)Pyruvate Dehydrogenase-This enzyme complex is comprised of 3 different enzymes which carry out 3 different functions-Start off with pyruvate and the enzyme, and during the oxidation of pyruvate, one of the carbons is oxidized to CO2 (first fully oxidized carbons from glucose to be generated in the process)-As pyruvate is oxidized, one of the molecules that in return is picking up those electronsand protons is NAD+, which helps generate NADH-NADH carries high energy electrons (preserve some of that energy in NADH)-You end up with acetate, which is combined with CoA, to form Acetyl CoA-What you get at the end is NADH, CO2, and Acetyl CoA-Results in additional carbon bonds that can be used to generate additional activated carriers-The sulfur carbon bond is a very high energy bond-CoA is a derivative of ATP***-This is all generating activated carriers from glucoseGenerating acetyl-CoA from fat-When you generate fatty acetyl-CoA, they go into a fatty acid oxidation cycle-Every round of this cycle, you strip off two carbons from the fatty acid-For every round you generate 1 FADH2 and 1 NADH-Because you’re oxidizing those bonds, the go to FAD and NAD+ to generate FADH2 and NADH-You are generating high energy carrier proteins-If you start with 4 carbons and go 1 round, it will result in…-2 acetyl-CoA-1 FADH2-1 NADH- If you start with 6 carbons and go 2 rounds, it will result in…-3 acetyl-CoA-2 FADH2-2 NADH- If you start with 12 carbons and go 5 rounds, it will result in…-6 acetyl-CoA-5 FADH2-5 NADH-All acetyl-CoA is being generated in the matrix of the mitochondria, and it is all used in the matrix of the mitochondria through the citric acid cycleCitric Acid Cycle-Also known as Krebs cycle-Completely oxidizing the acetyl group of acetyl-CoA to CO2-All of the other carbons that started out in glucose, the other 4 that are still there, are going to be oxidized to CO2 in the Citric Acid Cycle-This is the end of the process of oxidizing glucose-In eukaryotic cells, all of this cycle also occurs in the matrix of the mitochondria-You yield a lot of energy from those acetyl-CoA-1 GTP, 1 FADH2, and 3 NADH-Very high energy yield-This cycle doesn’t directly use oxygen (no oxygen that receives electrons, directly, in this process)-FAD and NAD are being reduced, meaning they are receiving -Indirectly uses oxygen by regenerating molecules that will receive -The enzyme citrate synthase is combining acetyl-CoA and oxaloacetate to generate ATP-In the first 2 steps, you make 2 NADH and oxidize 2 carbons to make 2 CO2s -Left with a 4-carbon molecule-Through the reactions, you oxidize the 4 carbons to form GTP, FADH2, and NADH to regenerate oxaloacetateGTP-GTP can be easily converted to ATP-When you generate GTP, just count it as an ATP because the bond contains the same amount of energy-Energetically equivalent-The problem is that enzymes are very specific for their substrates, so enzymes that bond to GTP can’t bond to ATP, so it needs to be convertedNAD+ vs. FAD-NAD is receiving two hydride ions from whatever molecule it is oxidizing-These are high energy electrons-FAD doesn’t receive hydride ions-NADH have a higher energy than those in FADHElectron-Transport Chain-Only step where oxygen is directly involved because you are directly reducing oxygen to water-NADH is fed into the electron transport chain in the first pump because they have high enough energy where they can be transported to another pump-FADH2 doesn’t have enough energy-Products are CO2 and H2O-Pumping protons, or releasing them from, these molecules and they are being released in the intermembrane space-Generating a pH and a charge difference between the intermembrane space and the matrix (the goal of the chain)-Taking energy from chemical bonds and generating a pH, charge, and concentration difference of protons across the membrane -Converting energy from one form (chemical bonds) to electrical and concentration gradients-ELECTRON-TRANSPORT CHAIN DRIVES OXIDATIVE PHOSPHORYLATIONATP Synthase-Has an opening that will allow protons to move from high concentration, or high positive charge, to the matrix which has a low proton concentration and a relatively low charge-Aligned to maximize the energy that is released-That energy is used to phosphorylate the process of ADP to