Oxidative Phosphorylation and Transport Chain PDF

Oxidative Phosphorylation © Teachable and Toby Tufton. Some rights reserved. http://teachable.net/res.asp?r=816 Oxidative H+ Phosphorylation...

Oxidative Phosphorylation © Teachable and Toby Tufton. Some rights reserved. http://teachable.net/res.asp?r=816 Oxidative H+ Phosphorylation Intermembrane space H+ + H Inner membrane Matrix - 2e 2e- reduced FAD oxidised here ATP synthase ADP red. NAD NAD Pi H+ 2H+ ½ O2 H2O ATP Terminal electron acceptor © Teachable and Toby Tufton. Some rights reserved. http://teachable.net/res.asp?r=816 Oxidative Phosphorylation ❑ Arrow(s) which show dehydrogenation ❑ The molecule which releases the most energy when it is oxidised (dehydrogenated) ❑ Any line or arrow which shows electron transfer ❑ Electron carriers ❑ Arrow(s) which show active transport of hydrogen ions - write H+ next to arrowhead(s) ❑ The phospholipid structure which is impermeable to H+ ions ❑ Arrow(s) which show diffusion of hydrogen ions - write H+ next to arrowhead(s) ❑ An enzyme ❑ Arrow(s) which show phosphorylation Labels © Teachable and Toby Tufton. Some rights reserved. http://teachable.net/res.asp?r=816 Oxidative Phosphorylation ❑ Arrow(s) which show dehydrogenation ❑ The molecule which releases the most energy when it is oxidised (dehydrogenated) ❑ Any line or arrow which shows electron transfer ❑ Electron carriers ❑ Arrow(s) which show active transport of hydrogen ions - write H+ next to arrowhead(s) ❑ The phospholipid structure which is impermeable to H+ ions ❑ Arrow(s) which show diffusion of hydrogen ions - write H+ next to arrowhead(s) ❑ An enzyme ❑ Arrow(s) which show phosphorylation © Teachable and Toby Tufton. Some rights reserved. http://teachable.net/res.asp?r=816 Oxidative Phosphorylation ❑ Arrow(s) which show dehydrogenation ❑ The molecule which releases the most energy when it is oxidised (dehydrogenated) ❑ Any line or arrow which shows electron transfer ❑ Electron carriers ❑ Arrow(s) which show active transport of hydrogen ions - write H+ next to arrowhead(s) ❑ The phospholipid structure which is impermeable to H+ ions ❑ Arrow(s) which show diffusion of hydrogen ions - write H+ next to arrowhead(s) ❑ An enzyme ❑ Arrow(s) which show phosphorylation © Teachable and Toby Tufton. Some rights reserved. http://teachable.net/res.asp?r=816 Oxidative Phosphorylation ❑ Arrow(s) which show dehydrogenation ❑ The molecule which releases the most energy when it is oxidised (dehydrogenated) ❑ Any line or arrow which shows electron transfer ❑ Electron carriers ❑ Arrow(s) which show active transport of hydrogen ions - write H+ next to arrowhead(s) ❑ The phospholipid structure which is impermeable to H+ ions ❑ Arrow(s) which show diffusion of hydrogen ions - write H+ next to arrowhead(s) ❑ An enzyme ❑ Arrow(s) which show phosphorylation © Teachable and Toby Tufton. Some rights reserved. http://teachable.net/res.asp?r=816 Oxidative Phosphorylation ❑ Arrow(s) which show dehydrogenation ❑ The molecule which releases the most energy when it is oxidised (dehydrogenated) ❑ Any line or arrow which shows electron transfer ❑ Electron carriers ❑ Arrow(s) which show active transport of hydrogen ions - write H+ next to arrowhead(s) ❑ The phospholipid structure which is impermeable to H+ ions ❑ Arrow(s) which show diffusion of hydrogen ions - write H+ next to arrowhead(s) ❑ An enzyme ❑ Arrow(s) which show phosphorylation © Teachable and Toby Tufton. Some rights reserved. http://teachable.net/res.asp?r=816 Oxidative Phosphorylation ❑ Arrow(s) which show dehydrogenation ❑ The molecule which releases the most energy when it is oxidised (dehydrogenated) ❑ Any line or arrow which shows electron transfer ❑ Electron carriers ❑ Arrow(s) which show active transport of hydrogen ions - write H+ next to arrowhead(s) ❑ The phospholipid structure which is impermeable to H+ ions ❑ Arrow(s) which show diffusion of hydrogen ions - write H+ next to arrowhead(s) ❑ An enzyme ❑ Arrow(s) which show phosphorylation © Teachable and Toby Tufton. Some rights reserved. http://teachable.net/res.asp?r=816 Oxidative Phosphorylation ❑ Arrow(s) which show dehydrogenation ❑ The molecule which releases the most energy when it is oxidised (dehydrogenated) ❑ Any line or arrow which shows electron transfer ❑ Electron carriers ❑ Arrow(s) which show active transport of hydrogen ions - write H+ next to arrowhead(s) ❑ The phospholipid structure which is impermeable to H+ ions ❑ Arrow(s) which show diffusion of hydrogen ions - write H+ next to arrowhead(s) ❑ An enzyme ❑ Arrow(s) which show phosphorylation © Teachable and Toby Tufton. Some rights reserved. http://teachable.net/res.asp?r=816 Oxidative Phosphorylation ❑ Arrow(s) which show dehydrogenation ❑ The molecule which releases the most energy when it is oxidised (dehydrogenated) ❑ Any line or arrow which shows electron transfer ❑ Electron carriers ❑ Arrow(s) which show active transport of hydrogen ions - write H+ next to arrowhead(s) ❑ The phospholipid structure which is impermeable to H+ ions ❑ Arrow(s) which show diffusion of hydrogen ions - write H+ next to arrowhead(s) ❑ An enzyme ❑ Arrow(s) which show phosphorylation © Teachable and Toby Tufton. Some rights reserved. http://teachable.net/res.asp?r=816 Oxidative Phosphorylation ❑ Arrow(s) which show dehydrogenation ❑ The molecule which releases the most energy when it is oxidised (dehydrogenated) ❑ Any line or arrow which shows electron transfer ❑ Electron carriers ❑ Arrow(s) which show active transport of hydrogen ions - write H+ next to arrowhead(s) ❑ The phospholipid structure which is impermeable to H+ ions ❑ Arrow(s) which show diffusion of hydrogen ions - write H+ next to arrowhead(s) ❑ An enzyme ❑ Arrow(s) which show phosphorylation © Teachable and Toby Tufton. Some rights reserved. http://teachable.net/res.asp?r=816 Oxidative Phosphorylation ❑ Arrow(s) which show dehydrogenation ❑ The molecule which releases the most energy when it is oxidised (dehydrogenated) ❑ Any line or arrow which shows electron transfer ❑ Electron carriers ❑ Arrow(s) which show active transport of hydrogen ions - write H+ next to arrowhead(s) ❑ The phospholipid structure which is impermeable to H+ ions ❑ Arrow(s) which show diffusion of hydrogen ions - write H+ next to arrowhead(s) ❑ An enzyme ❑ Arrow(s) which show phosphorylation © Teachable and Toby Tufton. Some rights reserved. http://teachable.net/res.asp?r=816  Let’s see this in action… https://www.youtube.com/watch?v=xbJ0nbzt 5Kw  Oxidative Phosphorylation A process that couples the oxidation of NADH and FADH2 by the electron transport chain with the synthesis of ATP by phosphorylation of ADP Electron Transport Chain (ETC) The Electron Transport Chain is a series of electron carriers and proteins that are embedded in the inner membrane of the mitochondrion Electrons donated by NADH and FADH2 are transported through the chain, providing the energy needed for oxidative phosphorylation It is not until the end of this part of the overall process of aerobic respiration that oxygen acts as an electron acceptor and is converted to water  NAD+ and FAD When NAD+ accepts electrons, it accepts two electrons and one hydrogen ion FAD accepts two electron and two hydrogen ions when NADH and FADH2 pass these electrons on to the electron acceptors in the ETC, they pass only one at a time and the hydrogen ions do not accompany the electrons, but instead say in the matrix  Electron Transport Chain The components of the ETC are arranged in order of increasing electronegativity, from weakest to strongest: 1. NADH dehydrogenase 2. Ubiquinone 3. Cytochrome b-c1 complex 4. Cytochrome c 5. Cytochrome oxidase complex  Cont. NADH passes its electrons on to the first protein complex, NADH dehyrodgenase, and FADH2 transfers its electrons to Ubiquinone, the second component of the chain The electrons are passed down this chain of proteins. As they move down, they lose potential energy. This energy is used to pump H+ ions from the matrix into the fluid filled intermembrane space. The enzyme cytochrome oxidase catalyzes the reaction between the electrons, protons (H+ions), and oxygen to form water For every H+ ion pumped out of the matrix, 1 ATP is made; the result is that 2ATP are formed per FADH2 and 3ATP are formed per NADH FADH2= 2ATP, NADH= 3ATP  Chemiosmosis Chemiosmosis is a process that uses energy in a hydrogen ion gradient across the inner mitochondrial membrane to drive phosphorylation of ADP to ATP As protons (H+ ions) accumulate in the intermembrane space, there are two gradients that are established: chemical and electrical  increased number of protons establishes a concentration gradient (chemical gradient) increased intensity of positive charge establishes an electrical gradient the increased electrochemical gradient across the inner mitochondrial membrane creates a “battery” effect where the potential for H+ ions to move back into the matrix is high - the free energy stored in the electrochemical gradient is referred to as a proton motive force (PMF)  Cont. the intermembrane space becomes a H+ reservoir since the inner mitochondrial membrane is impermeable to H+ ions since the protons (H+ ions) cannot diffuse through the lipid bilayer of the inner membrane, they are forced to move through the ATP synthase complex the PMF drives the hydrogen ions to move back into the matrix, via ATP synthase When electrons are moving down their gradient through an ATP synthase complex, the energy is used to phosphorylate ADP to form ATP – chemiosmosis.  What does this all Mean? Purpose of cellular respiration = to create ATP! Summary of Cellular Respiration: The overall purpose of these ‘domino’ reactions is to take the potential energy stored in the bonds of glucose and release it, so it can charge the “chemiosmotic battery” in the mitochondrion, which will power ATPase to phosphorylate ADP into ATP.  Let’s see all of this together http://www.youtube.com/watch?v=1KgDX DLZNJI https://www.youtube.com/watch?v=4Eo7Jt RA7lg Interconnections and Metabolic Pathways What nutrients are present in this meal?  A healthy diet consists more than glucose Depending on the nutrients, it goes through a different metabolic processes. Note how an amino acid can become a pyruvate directly avoiding glycolysis  Regulation of Aerobic Catabolic Pathways How does the cell determine and control the rate to generate ATP? 2 major enzymes are controlled by feedback mechanisms 1. phosphofructokinase: glycolysis - It has an allosteric binding site for ATP. When the cell has sufficient ATP, excess ATP binds to the site and inhibits the enzyme  2. conversion of pyruvate into acetyl-CoA and carbon dioxide Enzyme that catalyzes this reaction, pyruvate dehydrogenase, is inhibited by excess NADH. 3. many other Krebs cycle enzymes are also inhibited by excess ATP, NADH, and acetyl-CoA (see figure 3.16 pg 132)