Lecture 9.pdf

Located in the inner mitochondrial membrane (Review structure of mitochondria!) Most mitochondria are found in cells requiring lots of energy Oxidative phosphorylation Another way to make ATP ETC and ATP synthesis High energy electron carriers NADH and FADH2 bring electrons to the ETC 3 electrons fr...

Located in the inner mitochondrial membrane (Review structure of mitochondria!) Most mitochondria are found in cells requiring lots of energy Oxidative phosphorylation Another way to make ATP ETC and ATP synthesis High energy electron carriers NADH and FADH2 bring electrons to the ETC 3 electrons from NADH, 2 electrons from FADH2 Each complex has cytochromes and iron-sulfur centers iron-sulfur centers transfer the high energy electrons Cytochromes hold more tightly to electrons Loading… Proton motive force: the proton concentration gradient and the voltage gradient across the inner mitochondrial membrane NADH and NAD+ are a redox pair Loading… 100 ATP/sec Metabolites have to enter and leave the mitochondria for oxidative phosphorylation to work. Summary of Aerobic Respiration Glycolysis: – 1glucose to 2 pyruvate – Cytosol – 2 ATP, 2 NADH 2 pyruvate oxidized to 2 Acetyl CoA – 2 NADH, 2 CO2 – matrix Citric Acid Cycle – Matrix – 2 acetyl CoA used – 2 ATP(GTP), 6 NADH, 2 FADH2, 4 CO2 Oxidative phosphorylation – Across inner membrane – 2.5 ATP per NADH, 1.5 ATP per FADH2 = over 30 ATP per glucose How many ATP come from one molecule of glucose going through glycolysis and the TCA? How many come from oxidative phosphorylation? Which molecule below is reduced? Is FADH2 reduced or oxidized? Loading… What happens to the redox potential of the ETC components as you follow the electron through the chain? Which are better electron donors? Which are better electron receptors? Where do the electrons finally end up? What happens to the free energy of the electrons as they move through the ETC? Draw the ETC components in a membrane. Label each component. Label the membrane the ETC is located in as well as the spaces on either side. Indicate where NADH and FADH2 donate electrons. Include where the electrons finally end up (what molecule). Loading… How many ATP are made for each NADH? How many ATP are made for each FADH2? The citric acid cycle generates NADH and FADH2, which are then used in the process of oxidative phosphorylation to make ATP. If the citric acid cycle, which does not use oxygen, and oxidative phosphorylation are separate processes, as they are, then why is it that the citric acid cycle stops almost immediately upon removal of O2? The citric acid cycle stops without oxygen because oxygen is needed indirectly for the regeneration of molecules like NAD+ and FAD, which are crucial for the cycle to continue. What would happen if the proton motive force were reversed? ATP synthase would function in reverse, acting as an ATPase instead of an ATP synthase. This means that instead of synthesizing ATP, the enzyme would hydrolyze ATP to ADP and inorganic phosphate, releasing energy in the process. What type of transport is used to move pyruvate into the matrix? Pi into the matrix? ATP into the intermembrane space? (4 Artificial ATP synthesis machine