ETC/CHEMIOSIS. By: Leslie, Kelsey, Morgan

Transcription

1 ETC/CHEMIOSIS By: Leslie, Kelsey, Morgan

2 WHY THIS IS IMPORTANT House Clip SO3E7 The Son of a Coma Guy- Time: 32:00 Patient was visiting his father who was in a vegetative state for 10 years, and his only living relative, when House caused him to have a grand mal seizure by quickly turning the lights on and off causing him to become disoriented and was not able to see things as they were moving. He was admitted to the hospital and given seizure meds which coupled with his alcoholism sent him into liver failure, than renal failure and slowly all his organs began shutting down House woke his father up to get a complete family history as the son didn t know anything about his other relatives or how they all died.

3 ETC ETC stands for Electron Transport Chain The ETC is the inner mitochondrial membrane Eventually used to transport H+ to a series of components (mostly protein) The components are arranged in order of least to greatest electronegativity(nadh Dehydrogenase, the cytochrome b-c 1 complex, and the cytochrome oxidase complex Ubiquinone a.k.a Q and cytochrome c are electon mobile carriers Each component is reduced and oxidized, by gaining electrons from the component behind it and losing them to the one in front As the electrons move through the ETC they become more and more stable as they change position within the atom in comparison to the nuclei The free energy released from this process is used to pull H+ from the matrix into the mitochondria through the three proton pumps

4 THE ELECTRON TRANSPORT CHAIN* *Also known as Oxidative Phosphorylation

5 DIFFERENCES BETWEEN NADH AND FADH 2 NADH FADH 2 Passes it s electrons into NADH Dehydrogenase Free energy released from NADH oxidation pumps and produces 3 ATP molecules NADH produced in glycolysis May diffuse through outer mitochondria membrane into inter-membrane space but can t go through the inner membrane Has two shuttles to pass through the inter-membrane space into the matrix: Glycerolphosphate where it goes to FAD and produces FADH 2 and the Asparate where it goes to NAD + and produces NADH NADH produced in pyruvate oxidation and Krebs Transfers electrons into Q(Ubiquinone) Free energy released from FADH 2 oxidations pumps and produces 2 ATP molecules

6 THE PROCESS NADH Gives up two electrons to the first protein (NADH Dehydrogenase) Mobile electron carriers, Q and cytochrome c push the electrons from complex to complex until they reach the cytochrome oxidase complex where oxygen strips the electrons from the final protein complex The enzymes in the cytochrome oxidase complex catalyze the reaction (between electrons, protons and oxygen) to form water The free energy converts from potential energy into electrochemical potential energy(type of stored energy used in batteries) This energy will be stored in an electrochemical gradient to be used during chemiosmosis

7 CHEMIOSMOSIS Called chemiosmosis by Dr. Peter Mitchell because the energy that drives the synthesis of ATP comes from the osmosis of protons through a membrane from one compartment into another. Actual definition: A process for synthesizing ATP using the energy of an electrochemical gradient and the ATP synthase enzyme Forms 34 ATP molecules Turn to page 106

8 CHEMIOSMOSIS CONTINUED.. The electrochemical gradient has two components: an electrical one caused by the inter-membrane space having a higher positive charge than the matrix and a chemical one caused by the inter-membrane space having a higher concentration of protons than the matrix thus the intermembrane space becomes a H + reservoir This causes a voltage across the inner mitochondrial membrane forcing the protons to pass through channels associated with the enzyme ATP Synthase. The energy stored in the electrochemical gradient produces PMF (proton-motive forces) that move the protons through the ATP Synthase complex where the energy is reduced and drives the synthesis of ATP from ADP and P i in the matrix

9 CHEMIOSMOSIS CONTINUED.. So than the free energy lost by the electrochemical gradient is harvested as chemical potential energy in ATP After the ATP molecules are formed they are transported through the membranes into the cytoplasm where they are used to drive endergonic processes

10 QUIZ What is the difference between NADH and FADH2? What did you take away from the House Clip?? Where is the ETC located? What is the actual definition of chemiosmosis? How many ATP molecules does chemiosmosis form?