The document discusses two processes that cells use to synthesize ATP - oxidative phosphorylation and photophosphorylation. Both processes involve the flow of electrons through a transport chain coupled to the transport of protons across a membrane. Energy from the electron transport is used to pump protons against their gradient, and when protons flow back through ATP synthase, the energy is used to phosphorylate ADP into ATP. The chemiosmotic theory proposed that this is how cells harness energy to drive the endergonic formation of ATP from ADP and phosphate.
ATP synthase—also called FoF1 ATPase is the universal protein that terminates oxidative phosphorylation by synthesizing ATP from ADP and phosphate.
ATP Synthase is one of the most important enzymes found in the mitochondria of cells
This document summarizes ATP synthesis via oxidative phosphorylation and photophosphorylation. It describes how electron transport chains in the mitochondria and chloroplasts establish proton gradients across membranes, which are then used by ATP synthase complexes to phosphorylate ADP and produce ATP. Specifically, it outlines how electrons from NADH/FADH2 or water power proton pumping via complex I-IV in mitochondria or photosystems I and II in chloroplasts. The resulting proton gradient drives ATP synthesis when protons flow back through the ATP synthase.
This document summarizes the biosynthesis of various amino acids from different metabolic precursors. It discusses 6 main families of amino acid biosynthesis defined by their precursor: (1) α-ketoglutarate family including glutamate, glutamine, proline, and arginine; (2) 3-phosphoglycerate family including serine, glycine, and cysteine; (3) oxaloacetate family including aspartate, asparagine, methionine, threonine, and lysine; (4) pyruvate family including alanine, valine, leucine, and isoleucine; (5) phosphoenolpyruvate and erythrose 4-phosphate
The document discusses the chemiosmotic hypothesis, which explains how ATP synthesis is coupled to the electron transport chain. It states that (1) as electrons move through complexes I, III, and IV of the electron transport chain, protons are pumped from the mitochondrial matrix to the intermembrane space, building a proton gradient. (2) This proton gradient provides the energy for ATP synthase (Complex V) to catalyze the phosphorylation of ADP to ATP. Specifically, protons reenter the matrix through ATP synthase, driving the rotation of its membrane domain and causing conformational changes that lead to ATP production.
COVALENT MODIFICATION AND ZYMOGEN ACTIVATIONMariya Raju
1) Covalent modifications, both reversible and irreversible, play important roles in regulating enzyme function. Reversible modifications like phosphorylation fine-tune enzyme activity, while irreversible proteolysis activates zymogens into active enzymes.
2) Digestive enzymes like trypsinogen are synthesized as inactive zymogens to avoid unwanted catalysis, then activated through limited and specific proteolysis. This proteolysis removes inhibitory peptide sequences and allows catalytic activity.
3) Activation of zymogens through proteolytic cascades amplifies hormonal signals, allowing a small stimulus to elicit a large response. This cascade activation greatly increases the potency and efficiency of regulation compared to direct hormone binding.
The document discusses the urea cycle, which is the process by which excess nitrogen from amino acid catabolism is converted to urea for excretion. It describes the six amino acids and five enzymes involved in the cyclic urea formation reactions, which take place in the liver. Defects in the urea cycle enzymes can cause hyperammonemia due to the buildup of toxic ammonia, often presenting in newborns but sometimes not until later in life. Laboratory tests of blood ammonia levels, amino acid levels, and genetic testing can help diagnose specific urea cycle disorders.
The document discusses the key components of the cytoskeleton - microtubules, microfilaments, and intermediate filaments - and how they work together to maintain cell shape, allow movement of organelles and vesicles, transport materials within the cell, and enable cell movement through polymerization and interaction with motor proteins like myosin and kinesin. The cytoskeleton is a dynamic network that forms various structures through accessory proteins and allows rapid changes in cell morphology.
ATP synthase—also called FoF1 ATPase is the universal protein that terminates oxidative phosphorylation by synthesizing ATP from ADP and phosphate.
ATP Synthase is one of the most important enzymes found in the mitochondria of cells
This document summarizes ATP synthesis via oxidative phosphorylation and photophosphorylation. It describes how electron transport chains in the mitochondria and chloroplasts establish proton gradients across membranes, which are then used by ATP synthase complexes to phosphorylate ADP and produce ATP. Specifically, it outlines how electrons from NADH/FADH2 or water power proton pumping via complex I-IV in mitochondria or photosystems I and II in chloroplasts. The resulting proton gradient drives ATP synthesis when protons flow back through the ATP synthase.
This document summarizes the biosynthesis of various amino acids from different metabolic precursors. It discusses 6 main families of amino acid biosynthesis defined by their precursor: (1) α-ketoglutarate family including glutamate, glutamine, proline, and arginine; (2) 3-phosphoglycerate family including serine, glycine, and cysteine; (3) oxaloacetate family including aspartate, asparagine, methionine, threonine, and lysine; (4) pyruvate family including alanine, valine, leucine, and isoleucine; (5) phosphoenolpyruvate and erythrose 4-phosphate
The document discusses the chemiosmotic hypothesis, which explains how ATP synthesis is coupled to the electron transport chain. It states that (1) as electrons move through complexes I, III, and IV of the electron transport chain, protons are pumped from the mitochondrial matrix to the intermembrane space, building a proton gradient. (2) This proton gradient provides the energy for ATP synthase (Complex V) to catalyze the phosphorylation of ADP to ATP. Specifically, protons reenter the matrix through ATP synthase, driving the rotation of its membrane domain and causing conformational changes that lead to ATP production.
COVALENT MODIFICATION AND ZYMOGEN ACTIVATIONMariya Raju
1) Covalent modifications, both reversible and irreversible, play important roles in regulating enzyme function. Reversible modifications like phosphorylation fine-tune enzyme activity, while irreversible proteolysis activates zymogens into active enzymes.
2) Digestive enzymes like trypsinogen are synthesized as inactive zymogens to avoid unwanted catalysis, then activated through limited and specific proteolysis. This proteolysis removes inhibitory peptide sequences and allows catalytic activity.
3) Activation of zymogens through proteolytic cascades amplifies hormonal signals, allowing a small stimulus to elicit a large response. This cascade activation greatly increases the potency and efficiency of regulation compared to direct hormone binding.
The document discusses the urea cycle, which is the process by which excess nitrogen from amino acid catabolism is converted to urea for excretion. It describes the six amino acids and five enzymes involved in the cyclic urea formation reactions, which take place in the liver. Defects in the urea cycle enzymes can cause hyperammonemia due to the buildup of toxic ammonia, often presenting in newborns but sometimes not until later in life. Laboratory tests of blood ammonia levels, amino acid levels, and genetic testing can help diagnose specific urea cycle disorders.
The document discusses the key components of the cytoskeleton - microtubules, microfilaments, and intermediate filaments - and how they work together to maintain cell shape, allow movement of organelles and vesicles, transport materials within the cell, and enable cell movement through polymerization and interaction with motor proteins like myosin and kinesin. The cytoskeleton is a dynamic network that forms various structures through accessory proteins and allows rapid changes in cell morphology.
Membranes cover the surface of cells and surround organelles within cells. They serve several functions including maintaining cellular integrity by keeping components inside, selectively controlling movement of molecules in and out, and allowing cellular processes to occur separately within organelles. The plasma membrane forms the boundary of the cell and is made of a phospholipid bilayer with various embedded and attached proteins and carbohydrates. It regulates what enters and exits the cell.
Glycolysis is the breakdown of glucose to pyruvate through a series of enzyme-catalyzed reactions. It occurs in the cytosol and consists of a preparatory phase requiring ATP and a payoff phase generating ATP. Key steps include phosphorylation by hexokinase, aldolase cleavage, substrate-level phosphorylation by phosphoglycerate kinase, and pyruvate formation by pyruvate kinase. Glycolytic enzymes are regulated by feedback inhibition and metabolites like fructose 2,6-bisphosphate and AMP/ATP ratios to control flux through the pathway.
Membrane transport involves selective transport of solutes across membranes via transport proteins. There are three main types of transport: passive transport via diffusion, facilitated transport via carrier proteins, and active transport via pumps which move solutes against concentration gradients using ATP. Key transport proteins include carrier proteins that selectively transport particular solutes, ion channels that selectively transport ions, and the sodium-potassium pump which actively transports sodium and potassium ions out and into cells respectively to maintain electrochemical gradients.
A membrane protein is a protein molecule that is attached to, or associated with the membrane of a cell or an organelle.
More than half of all proteins interact with membranes.
Oxidative phosphorylation and photophosphorylation are the two main mechanisms by which organisms generate ATP. In oxidative phosphorylation, electrons are passed through an electron transport chain in mitochondria to reduce oxygen to water, pumping protons across the inner mitochondrial membrane. The resulting proton gradient is used by ATP synthase to phosphorylate ADP to ATP. Photophosphorylation uses sunlight to drive electron transport and proton pumping across thylakoid membranes in chloroplasts to similarly synthesize ATP. Both mechanisms conserve the energy of electron transport as a proton gradient that is then used to power ATP synthesis, demonstrating the fundamental similarity between these critical energy conversion processes.
This document summarizes the synthesis of purines and pyrimidines, which are nitrogenous bases that along with pentose sugars and phosphate groups make up nucleotides. It describes that purines adenine and guanine and pyrimidines cytosine, thymine, and uracil are components of both DNA and RNA. The synthesis of purine nucleotides involves ten steps to form inosine monophosphate, followed by two additional steps to form adenosine monophosphate and guanosine monophosphate. Pyrimidine synthesis involves six steps beginning with carbamoyl phosphate and aspartate to form a pyrimidine ring and ultimately uridine monophosphate. Rate of DNA synthesis can
Chapter 16 - The citric acid cycle - BiochemistryAreej Abu Hanieh
The document discusses cellular respiration, which occurs in three stages: 1) acetyl-CoA production from organic fuels like glucose and fatty acids, 2) acetyl-CoA oxidation in the citric acid cycle (CAC) to produce NADH, FADH2, and GTP, and 3) oxidative phosphorylation to generate large amounts of ATP. The citric acid cycle involves a series of chemical reactions that generate energy in the form of ATP, NADH, and FADH2. These stages capture energy from nutrients and transfer it to ATP via electron transport chains located in cellular organelles like mitochondria.
The document summarizes the structure and function of microtubules in eukaryotic cells. It discusses how microtubules are composed of protein subunits that assemble into hollow tubes. Microtubules emanate from microtubule organizing centers and serve important roles as structural supports, in intracellular transport through motor proteins like kinesin and dynein, and in cell division through formation of the mitotic spindle. Microtubules are also the main components of cilia and flagella and enable their bending movements through the motor protein dynein.
1. Proteins in eukaryotic cells are synthesized in the cytosol but must be targeted to various intracellular destinations like organelles. They use signal sequences and membrane receptors to direct their transport.
2. In the ER, proteins are modified through glycosylation and folding before being sent to the Golgi apparatus for further processing and sorting to their final locations like the plasma membrane or lysosomes.
3. Mitochondria and chloroplasts import proteins using signal sequences after full synthesis, while nuclear transport relies on non-cleaved NLS sequences and importin proteins.
4. Bacteria also use cleaved signal sequences and chaperones to transport proteins through membrane complexes. Cells import proteins through receptor-mediated
I have tried to make a precise presentation on protein transport, targeting and sorting into organelle's other than nucleus. Hope this might help you. Comments are welcome.
This ppt describes the overview of enzyme regulation and Allosterism. Presented since October 23,2017GC at Addis Ababa University, School of Medicine, Department of medical biochemistry.
1. Protein trafficking is the mechanism by which cells transport proteins to appropriate positions through lysosomes and vesicular transport.
2. Lysosomes contain acid hydrolases that digest molecules and organelles, while vesicular transport uses coated vesicles like clathrin-coated vesicles to move proteins between organelles.
3. Vesicle formation is regulated by GTP-binding proteins and adaptor proteins, while vesicle fusion is mediated by interactions between v-SNAREs on vesicles and t-SNAREs on target membranes through a process called the SNARE hypothesis.
The document discusses the composition and functions of the extracellular matrix (ECM) and cell-cell junctions. The ECM provides structural support to cells and regulates cell behavior. It is composed of fibrous proteins like collagen, polysaccharides like glycosaminoglycans, and adhesion proteins like fibronectin and laminin. Cells interact with the ECM through integrin receptors. Cell-cell junctions allow communication between cells and include adherens junctions, desmosomes, tight junctions, and gap junctions. The ECM and cell-cell junctions are essential for tissue structure and function.
Introduction-Cell wall and functions
Gram +ve and -ve cell wall
Bacterial cell wall - structure
Peptidoglycan-Composition and Structure
Types of polysaccharidesBacterial cell wall
Functions of polysaccharides in Bacterial cell wall
Chapter 19 - Oxidative Phosphorylation and Photophosphorylation- BiochemistryAreej Abu Hanieh
The document discusses two processes that cells use to synthesize ATP - oxidative phosphorylation and photophosphorylation. Both processes involve the flow of electrons through electron transport chains to establish a proton gradient across a membrane. In oxidative phosphorylation, the proton gradient is used by ATP synthase to phosphorylate ADP, while in photophosphorylation light provides the energy to drive the process in chloroplasts. The chemiosmotic theory proposes that it is the flow of protons back through ATP synthase, not a direct chemical reaction, that provides the energy for ATP synthesis.
Mitochondrial and bacterial electron transport, oxidation reduction by Akshay...HNGU
The document summarizes mitochondrial and bacterial electron transport. It describes the key components of the electron transport chain (ETC) in mitochondria, including four complexes and coenzyme Q that transfer electrons and pump protons. Bacterial ETCs can resemble mitochondria but vary in electron carriers and branches. They are usually shorter and less efficient than mitochondrial ETC. The ETC couples electron transfer with proton pumping to build a proton gradient and facilitate ATP synthesis through oxidative phosphorylation.
Membranes cover the surface of cells and surround organelles within cells. They serve several functions including maintaining cellular integrity by keeping components inside, selectively controlling movement of molecules in and out, and allowing cellular processes to occur separately within organelles. The plasma membrane forms the boundary of the cell and is made of a phospholipid bilayer with various embedded and attached proteins and carbohydrates. It regulates what enters and exits the cell.
Glycolysis is the breakdown of glucose to pyruvate through a series of enzyme-catalyzed reactions. It occurs in the cytosol and consists of a preparatory phase requiring ATP and a payoff phase generating ATP. Key steps include phosphorylation by hexokinase, aldolase cleavage, substrate-level phosphorylation by phosphoglycerate kinase, and pyruvate formation by pyruvate kinase. Glycolytic enzymes are regulated by feedback inhibition and metabolites like fructose 2,6-bisphosphate and AMP/ATP ratios to control flux through the pathway.
Membrane transport involves selective transport of solutes across membranes via transport proteins. There are three main types of transport: passive transport via diffusion, facilitated transport via carrier proteins, and active transport via pumps which move solutes against concentration gradients using ATP. Key transport proteins include carrier proteins that selectively transport particular solutes, ion channels that selectively transport ions, and the sodium-potassium pump which actively transports sodium and potassium ions out and into cells respectively to maintain electrochemical gradients.
A membrane protein is a protein molecule that is attached to, or associated with the membrane of a cell or an organelle.
More than half of all proteins interact with membranes.
Oxidative phosphorylation and photophosphorylation are the two main mechanisms by which organisms generate ATP. In oxidative phosphorylation, electrons are passed through an electron transport chain in mitochondria to reduce oxygen to water, pumping protons across the inner mitochondrial membrane. The resulting proton gradient is used by ATP synthase to phosphorylate ADP to ATP. Photophosphorylation uses sunlight to drive electron transport and proton pumping across thylakoid membranes in chloroplasts to similarly synthesize ATP. Both mechanisms conserve the energy of electron transport as a proton gradient that is then used to power ATP synthesis, demonstrating the fundamental similarity between these critical energy conversion processes.
This document summarizes the synthesis of purines and pyrimidines, which are nitrogenous bases that along with pentose sugars and phosphate groups make up nucleotides. It describes that purines adenine and guanine and pyrimidines cytosine, thymine, and uracil are components of both DNA and RNA. The synthesis of purine nucleotides involves ten steps to form inosine monophosphate, followed by two additional steps to form adenosine monophosphate and guanosine monophosphate. Pyrimidine synthesis involves six steps beginning with carbamoyl phosphate and aspartate to form a pyrimidine ring and ultimately uridine monophosphate. Rate of DNA synthesis can
Chapter 16 - The citric acid cycle - BiochemistryAreej Abu Hanieh
The document discusses cellular respiration, which occurs in three stages: 1) acetyl-CoA production from organic fuels like glucose and fatty acids, 2) acetyl-CoA oxidation in the citric acid cycle (CAC) to produce NADH, FADH2, and GTP, and 3) oxidative phosphorylation to generate large amounts of ATP. The citric acid cycle involves a series of chemical reactions that generate energy in the form of ATP, NADH, and FADH2. These stages capture energy from nutrients and transfer it to ATP via electron transport chains located in cellular organelles like mitochondria.
The document summarizes the structure and function of microtubules in eukaryotic cells. It discusses how microtubules are composed of protein subunits that assemble into hollow tubes. Microtubules emanate from microtubule organizing centers and serve important roles as structural supports, in intracellular transport through motor proteins like kinesin and dynein, and in cell division through formation of the mitotic spindle. Microtubules are also the main components of cilia and flagella and enable their bending movements through the motor protein dynein.
1. Proteins in eukaryotic cells are synthesized in the cytosol but must be targeted to various intracellular destinations like organelles. They use signal sequences and membrane receptors to direct their transport.
2. In the ER, proteins are modified through glycosylation and folding before being sent to the Golgi apparatus for further processing and sorting to their final locations like the plasma membrane or lysosomes.
3. Mitochondria and chloroplasts import proteins using signal sequences after full synthesis, while nuclear transport relies on non-cleaved NLS sequences and importin proteins.
4. Bacteria also use cleaved signal sequences and chaperones to transport proteins through membrane complexes. Cells import proteins through receptor-mediated
I have tried to make a precise presentation on protein transport, targeting and sorting into organelle's other than nucleus. Hope this might help you. Comments are welcome.
This ppt describes the overview of enzyme regulation and Allosterism. Presented since October 23,2017GC at Addis Ababa University, School of Medicine, Department of medical biochemistry.
1. Protein trafficking is the mechanism by which cells transport proteins to appropriate positions through lysosomes and vesicular transport.
2. Lysosomes contain acid hydrolases that digest molecules and organelles, while vesicular transport uses coated vesicles like clathrin-coated vesicles to move proteins between organelles.
3. Vesicle formation is regulated by GTP-binding proteins and adaptor proteins, while vesicle fusion is mediated by interactions between v-SNAREs on vesicles and t-SNAREs on target membranes through a process called the SNARE hypothesis.
The document discusses the composition and functions of the extracellular matrix (ECM) and cell-cell junctions. The ECM provides structural support to cells and regulates cell behavior. It is composed of fibrous proteins like collagen, polysaccharides like glycosaminoglycans, and adhesion proteins like fibronectin and laminin. Cells interact with the ECM through integrin receptors. Cell-cell junctions allow communication between cells and include adherens junctions, desmosomes, tight junctions, and gap junctions. The ECM and cell-cell junctions are essential for tissue structure and function.
Introduction-Cell wall and functions
Gram +ve and -ve cell wall
Bacterial cell wall - structure
Peptidoglycan-Composition and Structure
Types of polysaccharidesBacterial cell wall
Functions of polysaccharides in Bacterial cell wall
Chapter 19 - Oxidative Phosphorylation and Photophosphorylation- BiochemistryAreej Abu Hanieh
The document discusses two processes that cells use to synthesize ATP - oxidative phosphorylation and photophosphorylation. Both processes involve the flow of electrons through electron transport chains to establish a proton gradient across a membrane. In oxidative phosphorylation, the proton gradient is used by ATP synthase to phosphorylate ADP, while in photophosphorylation light provides the energy to drive the process in chloroplasts. The chemiosmotic theory proposes that it is the flow of protons back through ATP synthase, not a direct chemical reaction, that provides the energy for ATP synthesis.
Mitochondrial and bacterial electron transport, oxidation reduction by Akshay...HNGU
The document summarizes mitochondrial and bacterial electron transport. It describes the key components of the electron transport chain (ETC) in mitochondria, including four complexes and coenzyme Q that transfer electrons and pump protons. Bacterial ETCs can resemble mitochondria but vary in electron carriers and branches. They are usually shorter and less efficient than mitochondrial ETC. The ETC couples electron transfer with proton pumping to build a proton gradient and facilitate ATP synthesis through oxidative phosphorylation.
ETC and Phosphorylation by Salman SaeedSalman Saeed
ETC and Phosphorylation lecture for Biology, Botany, Zoology, and Chemistry Students by Salman Saeed lecturer Botany University College of Management and Sciences Khanewal, Pakistan.
About Author: Salman Saeed
Qualification: M.SC (Botany), M. Phil (Biotechnology) from BZU Multan.
M. Ed & B. Ed from GCU Faisalabad, Pakistan.
The ETC is a collection of proteins bound to the inner mitochondrial membrane and organic molecules, which electrons pass through in a series of redox reactions, and release energy. The energy released forms a proton gradient, which is used in chemiosmosis to make a large amount of ATP by the protein ATP-synthase.
B.Sc Micro II Microbial physiology Unit 2 Bacterial RespirationRai University
Respiration is the energy source to all living organism. Bacterial ETS system generates energy for bacteria in form of ATP using oxidative phosphorylation.
The electron transport chain is comprised of a series of enzymatic reactions within the inner membrane of the mitochondria, which are cell organelles that release and store energy for all physiological needs.
As electrons are passed through the chain by a series of oxidation-reduction reactions, energy is released, creating a gradient of hydrogen ions, or protons, across the membrane. The proton gradient provides energy to make ATP, which is used in oxidative phosphorylation.
This document provides an overview of chemioenergetics and oxidative phosphorylation. It discusses how mitochondria convert food into ATP through a series of redox reactions known as the electron transport chain located on the inner mitochondrial membrane. These reactions establish a proton gradient that is used by ATP synthase to phosphorylate ADP, producing ATP. Specifically, it describes (1) the structure and function of the electron transport chain complexes and enzymes, (2) how the chemiosmotic theory and proton gradient underlie ATP production, and (3) the binding change mechanism of ATP synthesis by ATP synthase. The document concludes that oxidative phosphorylation is the key process by which mitochondria generate cellular energy in the form of ATP.
Biochem Respiratory chain and Oxidative phosphorylationBlazyInhumang
The electron transport chain (ETC) is a series of complexes located in the inner mitochondrial membrane that shuttle electrons from electron carriers to oxygen. As electrons are passed through four protein complexes, protons are pumped from the mitochondrial matrix to the intermembrane space, generating an electrochemical gradient. ATP synthase harnesses this proton gradient to phosphorylate ADP, producing the majority of a cell's ATP through oxidative phosphorylation. The ETC and oxidative phosphorylation are essential metabolic pathways that generate energy to power cellular functions.
The document summarizes bioenergetics and metabolism. It discusses:
1) Metabolism, including catabolism which breaks down molecules to generate energy, and anabolism which builds molecules. The citric acid cycle and oxidative phosphorylation are described as the main catabolic pathways.
2) Glycolysis and how it feeds into the citric acid cycle, producing pyruvate. Fatty acid and amino acid oxidation also feed into the citric acid cycle.
3) The citric acid cycle which oxidizes acetyl-CoA completely to carbon dioxide, producing ATP, NADH, FADH2, and GTP. The cycle provides precursors for other processes.
The electron transport chain (ETC) transports electrons from electron donors like NADH to molecular oxygen. It consists of protein complexes embedded in the inner mitochondrial membrane. Complexes I, III, and IV pump protons out of the matrix, building up an electrochemical gradient used for ATP synthesis. Electrons flow from complex to complex via mobile carriers like coenzyme Q and cytochrome c. This transfers energy from electrons to protons, conserving energy as ATP. Mitochondria contain many copies of the ETC to generate sufficient ATP through oxidative phosphorylation.
Cellular respiration is a metabolic pathway that breaks down glucose and produces ATP. It occurs in three main stages: glycolysis, the citric acid cycle, and the electron transport chain. The electron transport chain generates the most ATP through oxidative phosphorylation, which uses a proton gradient established by pumping protons across membranes to power ATP synthase. Oxygen acts as the final electron acceptor in aerobic cellular respiration. Overall, cellular respiration breaks down glucose and other fuels to extract energy, producing carbon dioxide and water as waste products.
1) Biological oxidation involves the conversion of energy from foods like carbohydrates and lipids into ATP through electron transport chain and oxidative phosphorylation in mitochondria.
2) The electron transport chain involves a series of protein complexes that transfer electrons from electron donors like NADH to final acceptor oxygen, creating a proton gradient that drives ATP synthesis.
3) Through the chemiosmotic hypothesis, the potential energy of the proton gradient is used by ATP synthase to phosphorylate ADP into ATP, coupling electron transport to oxidative phosphorylation.
ETC is the transfer of electrons from NADH and FADH2 to oxygen via electron carriers. This releases energy to drive ATP synthesis from ADP and Pi. Multiple protein complexes make up the electron transport chain, passing electrons from one complex to the next until reaching oxygen. As electrons are passed, protons are pumped from the mitochondrial matrix to the intermembrane space, building up a proton gradient used for ATP production.
The document summarizes biochemical energy production through metabolism. It discusses catabolism and anabolism, metabolic pathways, the structures of prokaryotic and eukaryotic cells, and the four main stages of energy production: digestion, acetyl group formation, the citric acid cycle in mitochondria, and the electron transport chain and oxidative phosphorylation that generates ATP in mitochondria. The citric acid cycle and its role in producing NADH, FADH2, and GTP is described in detail.
The document provides information on cellular respiration and how it generates ATP through oxidative phosphorylation in the mitochondria. It discusses the electron transport chain, made up of protein complexes I-IV in the inner mitochondrial membrane, which establishes a proton gradient by pumping protons from the matrix to the intermembrane space. This proton gradient drives ATP synthase to catalyze the phosphorylation of ADP to ATP. The chemiosmotic theory explains how the potential energy in the proton gradient is used to produce ATP through rotation of the ATP synthase complex.
The document describes electron transport chain and oxidative phosphorylation. It discusses how the electron transport chain transfers electrons from NADH and FADH2 to oxygen. This establishes a proton gradient across the inner mitochondrial membrane. ATP synthase then uses this proton gradient to drive the phosphorylation of ADP to ATP, in a process called oxidative phosphorylation. The electron transport chain and oxidative phosphorylation are essential for aerobic respiration to generate the majority of the cell's ATP.
1) The document is an assignment submission on the electron transport chain from a student at PrimeAsia University.
2) It provides an overview of the electron transport chain as a series of protein complexes in the mitochondrial inner membrane that pass electrons from NADH and FADH2 through redox reactions to generate a proton gradient.
3) This proton gradient is then used by ATP synthase to produce ATP through chemiosmosis, completing oxidative phosphorylation.
The document summarizes the electron transport chain (ETC). The ETC is located in the mitochondria and is composed of a series of electron carriers that transfer electrons from donors like NADH and FADH2 to oxygen. As electrons flow from carrier to carrier, their energy is used to pump protons across the inner mitochondrial membrane, creating a proton gradient that drives ATP synthesis. The ETC consists of four complexes that transfer electrons step-wise to oxygen with complexes I, III, and IV pumping protons. The chemiosmotic hypothesis proposes that this proton gradient powers ATP synthase to generate ATP through oxidative phosphorylation.
The document discusses fatty acid catabolism. It states that oxidation of fatty acids is a major energy source for many organisms, providing about one-third of our energy needs. Fatty acids are an efficient way to store fuel, as they carry more energy per carbon than polysaccharides and require less water. Fatty acids are broken down into acetyl-CoA units through beta-oxidation in the mitochondria, generating energy rich NADH and FADH2. The acetyl-CoA then enters the citric acid cycle to be fully oxidized to CO2.
Carbohydrates range widely in size and structure, and serve important functions in living organisms. They are produced from carbon dioxide and water through photosynthesis in plants. Monosaccharides are the simplest carbohydrates and include sugars like glucose, galactose, and fructose. In solution, monosaccharides typically form ring structures called pyranoses or furanoses with intramolecular bonds. The cyclic forms exist in equilibrium with linear forms, and reducing sugars can be detected through chemical tests involving oxidation-reduction reactions. Modern methods for quantifying sugars like glucose use enzyme-based colorimetric or electrochemical assays.
Enzymes are biological catalysts that greatly accelerate chemical reactions in living organisms. They are typically proteins that precisely bind substrates in their active sites, properly orienting them and bringing reactive groups close together. This organization lowers the activation energy barrier for reactions. Enzymes achieve catalytic power by preferentially stabilizing the high-energy transition state of reactions more than the starting reactants or products. The active sites of enzymes are often complementary in shape and interactions to the transition states, not the ground states, of reactions.
Globular proteins serve many important functions in the body:
- They transport molecules like oxygen (hemoglobin) and glucose.
- They store ions and molecules for later use (myoglobin, ferritin).
- They catalyze biochemical reactions as enzymes.
Proteins interact with other molecules through their binding sites. The affinity between a ligand and protein binding site is described by the dissociation constant (Kd), with a lower Kd indicating tighter binding. This interaction is reversible and regulated by the rates of ligand binding and dissociation.
This document provides an overview of proteins, amino acids, and peptides. It discusses how proteins perform important biological functions like catalysis, transport, and structure. It describes how amino acids are the building blocks of proteins and the different classifications of amino acids. It also summarizes how peptides are formed from amino acids and some of their functions. Finally, it covers common techniques used to separate, analyze, and study proteins like chromatography, electrophoresis, and spectroscopy.
Glycolysis is a central pathway for glucose catabolism that converts glucose into pyruvate through a series of 10 enzyme-catalyzed reactions. It occurs in most organisms and tissues as a source of energy. The first phase activates glucose through phosphorylation, while the second phase generates ATP and NADH through substrate-level phosphorylation and hydride transfer. Pyruvate produced can then undergo aerobic or anaerobic fates including fermentation to regenerate NAD+ under anaerobic conditions.
The document discusses metabolic pathways and their regulation in living cells. It notes that biochemical reactions are organized into metabolic pathways that have dedicated purposes like extracting energy, storing fuels, and eliminating waste. Pathways work to maintain homeostasis by keeping metabolite concentrations at a steady state. Regulation of pathway flux occurs through changing the number or activity of regulatory proteins in response to various factors. This allows pathways to rapidly adapt flux as needed to environmental changes while maintaining homeostasis.
The document discusses cellular respiration, which occurs in three stages: 1) acetyl-CoA production from organic fuels like glucose and fatty acids, 2) acetyl-CoA oxidation in the citric acid cycle (CAC) to produce NADH, FADH2, and GTP, and 3) oxidative phosphorylation to generate large amounts of ATP. The citric acid cycle involves a series of chemical reactions that generate energy in the form of ATP, NADH, and FADH2. These stages capture energy from nutrients and facilitate the production of ATP to fuel cellular work.
Literature Review Basics and Understanding Reference Management.pptxDr Ramhari Poudyal
Three-day training on academic research focuses on analytical tools at United Technical College, supported by the University Grant Commission, Nepal. 24-26 May 2024
A SYSTEMATIC RISK ASSESSMENT APPROACH FOR SECURING THE SMART IRRIGATION SYSTEMSIJNSA Journal
The smart irrigation system represents an innovative approach to optimize water usage in agricultural and landscaping practices. The integration of cutting-edge technologies, including sensors, actuators, and data analysis, empowers this system to provide accurate monitoring and control of irrigation processes by leveraging real-time environmental conditions. The main objective of a smart irrigation system is to optimize water efficiency, minimize expenses, and foster the adoption of sustainable water management methods. This paper conducts a systematic risk assessment by exploring the key components/assets and their functionalities in the smart irrigation system. The crucial role of sensors in gathering data on soil moisture, weather patterns, and plant well-being is emphasized in this system. These sensors enable intelligent decision-making in irrigation scheduling and water distribution, leading to enhanced water efficiency and sustainable water management practices. Actuators enable automated control of irrigation devices, ensuring precise and targeted water delivery to plants. Additionally, the paper addresses the potential threat and vulnerabilities associated with smart irrigation systems. It discusses limitations of the system, such as power constraints and computational capabilities, and calculates the potential security risks. The paper suggests possible risk treatment methods for effective secure system operation. In conclusion, the paper emphasizes the significant benefits of implementing smart irrigation systems, including improved water conservation, increased crop yield, and reduced environmental impact. Additionally, based on the security analysis conducted, the paper recommends the implementation of countermeasures and security approaches to address vulnerabilities and ensure the integrity and reliability of the system. By incorporating these measures, smart irrigation technology can revolutionize water management practices in agriculture, promoting sustainability, resource efficiency, and safeguarding against potential security threats.
Electric vehicle and photovoltaic advanced roles in enhancing the financial p...IJECEIAES
Climate change's impact on the planet forced the United Nations and governments to promote green energies and electric transportation. The deployments of photovoltaic (PV) and electric vehicle (EV) systems gained stronger momentum due to their numerous advantages over fossil fuel types. The advantages go beyond sustainability to reach financial support and stability. The work in this paper introduces the hybrid system between PV and EV to support industrial and commercial plants. This paper covers the theoretical framework of the proposed hybrid system including the required equation to complete the cost analysis when PV and EV are present. In addition, the proposed design diagram which sets the priorities and requirements of the system is presented. The proposed approach allows setup to advance their power stability, especially during power outages. The presented information supports researchers and plant owners to complete the necessary analysis while promoting the deployment of clean energy. The result of a case study that represents a dairy milk farmer supports the theoretical works and highlights its advanced benefits to existing plants. The short return on investment of the proposed approach supports the paper's novelty approach for the sustainable electrical system. In addition, the proposed system allows for an isolated power setup without the need for a transmission line which enhances the safety of the electrical network
Using recycled concrete aggregates (RCA) for pavements is crucial to achieving sustainability. Implementing RCA for new pavement can minimize carbon footprint, conserve natural resources, reduce harmful emissions, and lower life cycle costs. Compared to natural aggregate (NA), RCA pavement has fewer comprehensive studies and sustainability assessments.
TIME DIVISION MULTIPLEXING TECHNIQUE FOR COMMUNICATION SYSTEMHODECEDSIET
Time Division Multiplexing (TDM) is a method of transmitting multiple signals over a single communication channel by dividing the signal into many segments, each having a very short duration of time. These time slots are then allocated to different data streams, allowing multiple signals to share the same transmission medium efficiently. TDM is widely used in telecommunications and data communication systems.
### How TDM Works
1. **Time Slots Allocation**: The core principle of TDM is to assign distinct time slots to each signal. During each time slot, the respective signal is transmitted, and then the process repeats cyclically. For example, if there are four signals to be transmitted, the TDM cycle will divide time into four slots, each assigned to one signal.
2. **Synchronization**: Synchronization is crucial in TDM systems to ensure that the signals are correctly aligned with their respective time slots. Both the transmitter and receiver must be synchronized to avoid any overlap or loss of data. This synchronization is typically maintained by a clock signal that ensures time slots are accurately aligned.
3. **Frame Structure**: TDM data is organized into frames, where each frame consists of a set of time slots. Each frame is repeated at regular intervals, ensuring continuous transmission of data streams. The frame structure helps in managing the data streams and maintaining the synchronization between the transmitter and receiver.
4. **Multiplexer and Demultiplexer**: At the transmitting end, a multiplexer combines multiple input signals into a single composite signal by assigning each signal to a specific time slot. At the receiving end, a demultiplexer separates the composite signal back into individual signals based on their respective time slots.
### Types of TDM
1. **Synchronous TDM**: In synchronous TDM, time slots are pre-assigned to each signal, regardless of whether the signal has data to transmit or not. This can lead to inefficiencies if some time slots remain empty due to the absence of data.
2. **Asynchronous TDM (or Statistical TDM)**: Asynchronous TDM addresses the inefficiencies of synchronous TDM by allocating time slots dynamically based on the presence of data. Time slots are assigned only when there is data to transmit, which optimizes the use of the communication channel.
### Applications of TDM
- **Telecommunications**: TDM is extensively used in telecommunication systems, such as in T1 and E1 lines, where multiple telephone calls are transmitted over a single line by assigning each call to a specific time slot.
- **Digital Audio and Video Broadcasting**: TDM is used in broadcasting systems to transmit multiple audio or video streams over a single channel, ensuring efficient use of bandwidth.
- **Computer Networks**: TDM is used in network protocols and systems to manage the transmission of data from multiple sources over a single network medium.
### Advantages of TDM
- **Efficient Use of Bandwidth**: TDM all
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2. Energy
from
reduced
fuels
is
used
to
synthesize
ATP
in
animals
• Carbohydrates,
lipids,
and
amino
acids
are
the
main
reduced
fuels
for
the
cell
• Their
oxida9ve
steps
converge
in
the
final
stage
of
cellular
respira9on
• Electrons
from
reduced
fuels
are
transferred
to
reduced
cofactors
NADH
or
FADH2
• In
oxida*ve
phosphoryla*on,
energy
from
NADH
and
FADH2
are
used
to
make
ATP
3. Oxida*ve
Phosphoryla*on
• Electrons
from
the
reduced
cofactors
NADH
and
FADH2
are
passed
to
proteins
in
the
respiratory
chain
• In
eukaryotes,
oxygen
is
the
ul9mate
electron
acceptor
for
these
electrons
• Energy
of
oxida9on
is
used
to
phosphorylate
ADP
4. Photophosphoryla*on
• In
photosynthe9c
organisms
light
causes
charge
separa9on
between
a
pair
of
chlorophyll
molecules
• Energy
of
the
oxidized
and
reduced
chlorophyll
molecules
is
used
to
drive
synthesis
of
ATP
• Water
is
the
source
of
electrons
that
are
passed
via
a
chain
of
protein
transporters
to
the
ul9mate
electron
acceptor,
NADP+
• Oxygen
is
the
byproduct
of
water
oxida9on
• Both
processes:
1. Involve
the
flow
of
e–s
through
a
chain
2. Coupled
to
an
endergonic
“uphill”
transport
of
protons
3. Flow
back
of
protons
provides
energy
for
making
ATP
5.
6. Chemiosmo*c
Theory
Ø
ADP
+
Pi
à
ATP
is
Highly
Thermodynamically
Unfavorable
• How
do
we
make
it
possible?
• Peter
Mitchell
proposed
the
chemiosmo(c
theory
(Noble
prize
in
chemistry,
1978)
• Phosphoryla9on
of
ADP
is
not
a
result
of
a
direct
reac9on
between
ADP
and
some
high-‐energy
phosphate
carrier
(substrate-‐level
phosphoryla9on)
• Energy
needed
to
phosphorylate
ADP
is
provided
by
the
flow
of
protons
down
the
electrochemical
gradient
• The
energy
released
by
electron
transport
is
used
to
transport
protons
against
the
electrochemical
gradient
7. Chemiosmo*c
energy
coupling
requires
membranes
• The
proton
gradient
needed
for
ATP
synthesis
can
be
stably
established
across
a
membrane
that
is
impermeable
to
ions
– Plasma
membrane
in
bacteria
– Inner
membrane
in
mitochondria
– Thylakoid
membrane
in
chloroplasts
• Membrane
must
contain
proteins
that
couple
the
“downhill”
flow
of
electrons
in
the
electron-‐transfer
chain
with
the
“uphill”
flow
of
protons
across
the
membrane
• Membrane
must
contain
a
protein
that
couples
the
“downhill”
flow
of
protons
to
the
phosphoryla9on
of
ADP
(oxida9ve
phosphoryla9on)
8. Chemiosmo*c
Theory
e–s move through a chain spontaneously, driven by the high reduction
potential of O2 and the low reduction potentials of the reduced
substrates
9. Flow
of
Protons:
Mitochondria,
Chloroplasts,
Bacteria
• According
to
endosymbio9c
theory,
mitochondria
and
chloroplasts
arose
from
entrapped
bacteria
• Bacterial
cytosol
became
mitochondrial
matrix
and
chloroplast
stroma
10. Structure
of
a
Mitochondrion
Double
membrane
leads
to
four
dis9nct
compartments:
1. Outer
Membrane:
– Rela9vely
porous
membrane
allows
passage
of
metabolites
– Permeable
to
solutes
<5000
Da
2. Intermembrane
Space
(IMS):
– similar
environment
to
cytosol
– higher
proton
concentra9on
(lower
pH)
3. Inner
Membrane
– Rela9vely
impermeable,
with
proton
gradient
across
it
– Loca9on
of
electron
transport
chain
complexes
– Convolu9ons
called
Cristae
serve
to
increase
the
surface
area
(9ssues
with
high
demand
for
aerobic
respira9on
contain
thousands
of
mito
and
their
cristae
are
more
densely
packed)
4. Matrix
– Loca9on
of
the
citric
acid
cycle
and
parts
of
lipid
and
amino
acid
metabolism
(all
fuel
oxida8on
pathways
except
glycolysis)
– Lower
proton
concentra9on
(higher
pH)
11. Structure
of
a
Mitochondrion
Defects
in
mito
func9on
have
serious
medical
consequences:
-‐ Neurodegenera9ve
diseases
-‐ Cancer
-‐ Diabetes
-‐ Obesity
ATP
produc9on
is
not
the
only
func9on
of
mito
-‐ Thermogenesis
-‐ Steroid
synthesis
-‐ Apoptosis
Divide
by
fission
12. Electron-‐transport
chain
complexes
contain
a
series
of
electron
carriers
• Nico*namide
nucleo*de-‐linked
dehydrogenases
use
NAD+
or
NADP+
(NAD+
in
catabolism
and
NADPH
in
anabolism)
-‐
Remove
2
e–s
and
hydrogen
atom
from
their
substrates
(:H–
to
NAD+
and
H+)
• Each
complex
contains
mul9ple
redox
centers
consis9ng
of:
– Flavin
Mononucleo*de
(FMN)
or
Flavin
Adenine
Dinucleo*de
(FAD)
• Ini9al
electron
acceptors
for
Complex
I
and
Complex
II
• Can
carry
two
electrons
by
transferring
one
at
a
8me
– Cytochromes
a,
b
or
c
– Iron-‐sulfur
clusters
13. Cytochromes
• One
electron
carriers
• a,
b
or
c
differ
by
ring
addi9ons
(light
absorp9on)
• Iron
coordina9ng
porphyrin
ring
deriva9ves
(9ghtly
but
not
covalently
bound
in
a
and
b
but
covalent
in
c)
14. Iron-‐Sulfur
Clusters
• One
electron
carriers
• Coordina9on
by
cysteines
in
the
protein
• Containing
equal
number
of
iron
and
sulfur
atoms
• Rieske
Fe-‐S
proteins
–
1
Fe
is
coordinated
to
two
His
instead
of
2
Cys)
• At
least
8
Fe-‐S
proteins
func9on
in
mitochondrial
ETC
15. Coenzyme
Q
or
Ubiquinone
• Ubiquinone
(Q)
is
a
lipid-‐soluble
conjugated
dicarbonyl
compound
that
readily
accepts
electrons
• Upon
accep9ng
two
electrons,
it
picks
up
two
protons
to
produce
an
alcohol,
ubiquinol
(QH2)
• Ubiquinol
can
freely
diffuse
in
the
membrane,
carrying
electrons
with
protons
from
one
side
of
the
membrane
to
another
side
• Coenzyme
Q
is
a
mobile
electron
carrier
transpor9ng
electrons
from
Complexes
I
and
II
to
Complex
III
16. Free
Energy
of
Electron
Transport
Reduc9on
Poten9al
(E)
∆Eʹ′o
=
Eʹ′o
(e-‐
acceptor)
–
Eʹ′o
(e-‐
donor)
∆G’o
=
–nF∆E’o
For
nega9ve
ΔG
need
posi9ve
ΔE
E(acceptor)
>
E(donor)
Electrons
are
transferred
from
lower
(more
nega9ve)
to
higher
(more
posi9ve)
reduc9on
poten9al.
Free
Energy
released
is
used
to
pump
proton,
storing
this
energy
as
the
electrochemical
gradient
17. Recall: reduction potential is the relative tendency of a given
chemical species to accept electrons in a redox reaction (the
higher the reduction potential the more oxidized the species)
We
would
expect
the
carriers
to
func9on
in
order
of
increasing
reduc9on
poten9al
(e–s
flow
spontaneously):
NADH
à
Q
à
cyt
b
à
cyt
c1
à
cyt
c
à
cyt
a
à
cyt
a3
à
O2
Not
necessarily
the
same
as
the
order
of
the
actual
reduc9on
poten9al,
but
this
sequence
was
confirmed
by
other
experiments
18. Flow
of
Electrons
from
Biological
Fuels
into
the
Electron-‐Transport
Chain
Ubiquinone (Q) is the point of
entry for electrons derived from
reactions in the cytosol, from fatty
acid oxidation, and from succinate
oxidation (in the citric acid cycle).
20. NADH
dehydrogenase
(Complex
I)
• One
of
the
largest
macro-‐molecular
assemblies
in
the
mammalian
cell
• Over
40
different
polypep9de
chains,
encoded
by
both
nuclear
and
mitochondrial
genes
• NADH
binding
site
in
the
matrix
side
• Non-‐covalently
bound
flavin
mononucleo9de
(FMN)
accepts
two
electrons
from
NADH
• Several
iron-‐sulfur
centers
pass
one
electron
at
a
9me
toward
the
ubiquinone
binding
site
• A
vectorial
proton
pump
(in
one
direc9on
only):
NADH
+
5H+
N
+
Q
à
NAD+
+
QH2
+
4H+
P
P
=
posi9ve
(IMS);
N
=
nega9ve
(matrix)
22. Succinate
Dehydrogenase
(Complex
II)
• Smaller
and
simpler
than
complex
I
• FAD
accepts
two
electrons
from
succinate
• Electrons
are
passed,
one
at
a
9me,
via
iron-‐sulfur
centers
to
ubiquinone,
which
becomes
reduced
QH2
• Does
not
transport
protons
23. Complex
II
3
2Fe-‐2S
Bound
FAD
Heme
b
Q
binding
site
Succinate
binding
site
C
and
D
(integral
proteins)
A
and
B
(matrix)
24. Ubiquinone:Cytochrome
c
Oxidoreductase,
(Complex
III)
• Uses
two
electrons
from
QH2
to
reduce
two
molecules
of
cytochrome
c
• Addi9onally
contains
iron-‐sulfur
clusters,
cytochrome
b’s,
and
cytochrome
c’s
• The
Q
cycle
results
in
four
addi9onal
protons
being
transported
to
the
IMS
26. The
Q
Cycle
• Experimentally,
four
protons
are
transported
across
the
membrane
per
two
electrons
that
reach
cyt
c
• Two
of
the
four
protons
come
from
QH2
• The
Q
cycle
provides
a
good
model
that
explains
how
two
addi9onal
protons
are
picked
up
from
the
matrix
• Two
molecules
of
QH2
become
oxidized,
releasing
protons
into
the
IMS
• One
molecule
becomes
re-‐reduced,
thus
a
net
transfer
of
four
protons
per
reduced
Coenzyme
Q
29. • The
second
mobile
electron
carrier
• A
soluble
heme-‐containing
protein
in
the
intermembrane
space
• Heme
iron
can
be
either
ferric
(Fe3+,
oxidized)
or
ferrous
(Fe2+,
reduced)
• Cytochrome
c
carries
a
single
electron
from
the
cytochrome
bc1
complex
to
cytochrome
oxidase
(to
a
binuclear
copper
center)
Cytochrome
c
30. Cytochrome
Oxidase
(Complex
IV)
• Mammalian
cytochrome
oxidase
is
a
membrane
protein
with
13
subunits
• Contains
two
heme
groups:
a
and
a3
• Contains
copper
ions
– CuA:
two
ions
that
accept
electrons
from
cyt
c
– CuB:
bonded
to
heme
a3
forming
a
binuclear
center
that
transfers
four
electrons
to
oxygen
31. Cytochrome
oxidase
passes
electrons
to
O2
• Four
electrons
are
used
to
reduce
one
oxygen
molecule
into
two
water
molecules
(coming
from
4
cyt
c
molecules)
• Four
protons
are
picked
up
from
the
matrix
in
this
process
• Four
addi9onal
protons
are
passed
from
the
matrix
to
the
intermembrane
space
35. Summary
of
Electron
Transport
• Complex
I
à
Complex
IV
1NADH
+
11H+
(N)
+
½O2
——>
NAD+
+
10H+
(P)
+
H2O
• Complex
II
à
Complex
IV
FADH2
+
6H+
(N)
+
½O2
——>
FAD
+
6H+
(P)
+
H2O
Difference
in
number
of
protons
transported
reflects
the
amount
of
synthesized
ATP.
36.
37. Energy
of
electron
transfer
is
efficiently
conserved
in
a
proton
gradient
NADH
+
H+
+
½
O2
à
NAD+
+
H2O
(Net)
∆Eʹ′o
=
Eʹ′o
(e-‐
acceptor)
–
Eʹ′o
(e-‐
donor)
=
0.816
–
(-‐0.32)
=
1.14
V
∆Gʹ′o
=
–
nF∆Eʹ′o
=
–
2
x
96.5
x
1.14
=
–
220
kJ/mol
of
NADH
Succinate
to
fumarate
oxida9on
yields
~
–
150
kJ/mol
Much
of
this
energy
is
used
to
pump
protons
(proton-‐mo*ve
force)
38. Proton-‐Mo*ve
Force
• 2
components:
1. Concentra9on
gradient
(of
protons)
2. Electrical
gradient
(+
and
–
ions
are
segregated)
• The
proteins
in
the
electron-‐transport
chain
created
the
electrochemical
proton
gradient
by
one
of
three
means:
– Ac9vely
transport
protons
across
the
membrane
• Complex
I
and
Complex
IV
– Chemically
remove
protons
from
the
matrix
• Reduc9on
of
CoQ
and
reduc9on
of
oxygen
– Release
protons
into
the
intermembrane
space
• Oxida9on
of
QH2
39. Proton-‐Mo*ve
Force
In
ac9vely
respiring
mito:
Δψ
~0.15
V
and
the
matrix
is
0.75x
more
alkaline
ΔG
=
(5.7x0.75)
+
(96.5x0.15)
=
19
kJ/mol
Since
2
e–s
from
NADH
leads
to
pumping
of
10
protons
è
roughly
190
kJ
of
the
220
kJ
released
by
NADH
oxida8on
is
conserved
in
the
proton
gradient!
40. Reac*ve
oxygen
species
(ROS)
can
damage
biological
macromolecules
When
the
rate
of
e–
entry
into
the
RC
and
the
rate
of
e–
transfer
through
the
chain
are
mismatched
è
superoxide
radical
(•O2
–)
produc9on
increases
(par9ally
reduced
ubiquinone
radical
(•Q–)
donates
an
electron
to
O2)
è
forma9on
of
the
highly
reac9ve
hydroxyl
free
radical
(•OH)
è
damaging
enzymes,
lipids
and
DNA
To
prevent:
superoxide
dismutase
&
glutathione
peroxidase
41. Chemiosmo*c
Model
for
ATP
Synthesis
•
Electron
transport
sets
up
a
proton-‐mo9ve
force
•
Energy
of
proton-‐mo9ve
force
(~190
kJ)
drives
synthesis
of
ATP
(requires
52
kJ)
see
worked
example
13-‐2
ADP + Pi + nH+
P à ATP + H2O + nH+
N
42. Consequently,
electron
transport
is
coupled
to
ATP
synthesis
Coupling:
• Electron
transport
requires
ATP
synthesis
• ATP
synthesis
requires
electron
transport
• Obligate!
Neither
process
can
proceed
without
the
other
43. Coupling
• O2
consump9on
and
ATP
synthesis
depends
on
the
presence
of
ADP
+
Pi
and
an
oxidizable
substrate
• Blocking
the
passage
of
e–s
to
O2
will
inhibit
ATP
produc9on
Addition of cyanide (CN-), which
blocks electron transfer between
cytochrome oxidase (Complex IV)
and O2, inhibits both respiration
and ATP synthesis.
44. Coupling
• If
ADP
is
not
available
succinate
cannot
be
oxidized
• Inhibi9ng
ATP
synthesis
will
inhibit
e–
transfer
to
O2
• Chemical
uncouplers
of
ATP
synthesis
from
e–
transport
dissipate
proton
gradients
(weak
hydrophobic
acids)
inhibitors of
ATP synthase
45. Mitochondrial
ATP
Synthase
Complex
• Mitochondrial
ATP
synthase
(complex
V)
is
an
F-‐type
ATPase
• Contains
two
func9onal
units:
– F1
• Peripheral
membrane
protein
complex
in
the
matrix
• On
its
own
catalyzes
the
hydrolysis
of
ATP
– Fo
• Integral
membrane
complex,
a
channel
• Oligomycin-‐sensi9ve
• Transports
protons
from
IMS
to
matrix,
dissipa9ng
the
proton
gradient
• Energy
transferred
to
F1
to
catalyze
phosphoryla9on
of
ADP
46. Mitochondrial
ATP
Synthase
Complex
• On
the
enzyme
surface,
ADP
+
Pi
ßà
ATP
+
H2O
is
readily
reversible
with
ΔG’
~
0!!
Why?
• The
enzyme
stabilizes
ATP
much
more
than
ADP,
more
9ghtly
bound
(Kd(ATP)
<
10–12
M;
Kd(ADP)
~
10–5
M)
• Binding
energy
of
~
40
kJ/mol
drives
the
synthesis
of
ATP
• If
no
proton
gradient
is
present,
ATP
cannot
leave
the
enzyme
surface
• To
con8nually
synthesize
ATP
the
enzyme
cycles
between
a
conforma8on
that
binds
ATP
very
8ghtly
(to
drive
synthesis)
and
a
conforma8on
that
releases
ATP
47. The
F1
catalyzes
ADP
+
Pi
ATP
• 9
subunits
α3β3γδε
• The
head
is
a
hexamer
arranged
in
three
αβ
dimers
• β
has
the
cataly9c
ac9vity
and
can
exist
in
three
different
conforma9ons
(γ
binds
only
one
of
the
3
β)
– Open:
empty
– Loose:
binding
ADP
and
Pi
– Tight:
catalyzes
ATP
forma9on
and
binds
product
48. Binding-‐Change
Model
(rota*onal
catalysis)
The
3
ac9ve
sites
take
turn
catalyzing
the
reac9on
driven
by
proton
entering
A
subunit
starts
with
β-‐ADP
conforma9on
It
changes
conforma9on
to
β-‐ATP,
stabilizing
ATP
on
enzyme
surface
Subunit
changes
to
β-‐empty
which
is
a
very
low
affinity
conforma9on
The position of γ
49. Coupling
Proton
Transloca*on
to
ATP
Synthesis
• Proton
transloca9on
causes
a
rota9on
of
the
Fo
subunit
and
the
central
sha{
γ
• This
causes
a
conforma9onal
change
within
all
the
three
αβ
pairs
• The
conforma9onal
change
in
one
of
the
three
pairs
promotes
condensa9on
of
ADP
and
Pi
into
ATP
51. Stoichiometry
of
O2
consump*on
and
ATP
Synthesis
• xADP
+
xPi
+
½
O2
+
H+
+
NADH
à
xATP
+
H2O
+
NAD+
• x
(P/O
ra*o)
=
number
of
ATP
molecules
synthesized
per
½
O2
(thought
to
be
an
integer)
• Switched
the
ques9on
to
how
many
protons
are
pumped
outward
and
how
many
protons
must
flow
back
in
to
make
ATP
• 10
H+
(from
NADH)
and
6
H+
(from
succinate)
are
pumped
out
per
electron
pair
• 4
H+
are
needed
to
flow
back
to
make
1
ATP
(3
to
turn
the
Fo
and
1
to
transport
Pi,
ATP
and
ADP)
è
proton-‐based
P/O
ra9os
are:
2.5
ATP/NADH
and
1.5
ATP/succinate
52. Transport
of
ADP
and
Pi
into
the
Matrix
Proton-motive force drives
the translocation of ADP in
and ATP out (net transport
of 1 –ve charge into the
+ve IMS Proton-motive force drives
the inward movement of
phosphate into the matrixAll three of these transport
systems can be isolated as a single
membrane-bound complex (ATP synthasome)
55. Regula*on
of
Oxida*ve
Phosphoryla*on
• Primarily
regulated
by
substrate
availability
– Acceptor
control
ra*o
–
maximal
rate
of
ADP-‐induced
O2
consump9on/basal
rate
(without
ADP)
~
>10
in
many
cells
– Mass
ac*on
ra*o
–
[ATP]/[ADP][Pi]
is
normally
very
high.
When
the
rate
of
energy-‐requiring
processes
é,
mass
ac9on
ra9oê
èéADP
available
for
OxPhos
è
respira9on
rateé
– ATP
is
formed
only
as
fast
as
it’s
used
in
energy-‐requiring
ac8vi8es
• Inhibitor
of
F1
(IF1)
– Prevents
hydrolysis
of
ATP
during
low
oxygen
– Binds
to
2
ATP
synthases
and
inhibits
their
ATPase
ac9vi9es
– Only
ac9ve
at
lower
pH,
encountered
when
electron
transport
is
slowed
(i.e.,
low
oxygen).
Recall
lac8c
acid
fermenta8on!
• Inhibi9on
of
OxPhos
leads
to
accumula9on
of
NADH
– Causes
feedback
inhibi9on
cascade
up
to
PFK-‐1
in
glycolysis
56. Regula*on
of
ATP-‐producing
pathways
All four pathways are
accelerated when the use of
ATP and the formation of ADP,
AMP, and Pi increase.
57. HIF
• Hypoxic
cells
è
Imbalance
between
e–
input
and
e–
transfer
to
O2
è
éROS
• Countered
by:
1. Increase
in
glycolysis
2. Inac9va9on
of
PDH
3. Replacement
of
COX
subunit
58. Brown
Adipose
Tissue
has
uncoupled
mito
• In
newborn
mammals,
BAT
serves
as
heat-‐genera9ng
9ssue
• Large
number
of
mito
è
large
number
of
cytochromes
è
looks
brown
• BAT
mito
have
an
uncoupling
protein
in
their
inner
membrane
(thermogenin)
which
is
a
proton
channel
• Path
for
protons
to
the
matrix
without
passing
through
FoF1
complex
è
short-‐circui9ng
of
protons
è
energy
is
not
conserved
as
ATP
by
lost
as
heat
• Also
in
hiberna9ng
animals
59. Steroidogenesis
• Steroids
are
synthesized
from
cholesterol
in
a
series
of
hydroxyla9ons
catalyzed
by
cytochrome
P-‐450
• R-‐H
+
O2
+
NADPH
+
H+
à
R-‐OH
+
H2O
+
NADP+
• Steroidogenic
cells
(e.g.
adrenal
glands)
are
packed
with
specialized
mitochondria
for
steroid
synthesis
î
• P-‐450
are
also
found
in
ER,
responsible
for
metabolism
of
xenobio*cs
• Hydroxyla9on
è
more
water
soluble
è
more
excre9on
in
urine
• Many
prescrip9on
drugs
are
substrates
for
P-‐450
è
P-‐450
ac9vity
limits
the
drugs’
life9me
and
efficacy
• Humans
differ
in
their
P-‐450
contents
and
ac9vi9es
in
their
cells
è
an
individual’s
gene9cs
and
personal
history
could
have
a
say
in
determining
therapeu9c
drug
dose
or
form
60. Mitochondrial
damage
ini*ates
apoptosis
• Apoptosis
–
Individual
cells
die
for
the
benefit
of
the
organism
• Ini9ated
by
external
signals
or
internal
events
• Early
consequence
of
death
signals
in
the
increase
in
MOM
permeability
to
proteins
• What
causes
this
permeability?
(My
Ph.D.
research
J)
• Cytochrome
c
(and
others)
is
released
into
the
cytosol
• 7
molecules
of
cyt
c
form
an
apoptosome
with
7
Apaf-‐1
• Allow
the
docking
and
ac9va9on
of
procaspase-‐9
• Cleaves
procaspase-‐9
(inac9ve)
to
caspase-‐9
(ac9ve)
which
cleaves
and
ac9vates
procaspase-‐3
and
7
(into
caspase-‐3
and
caspase-‐7)
which
is
an
execu9oner
caspase
(breaks
down
the
macromolecular
contents
of
cells)
• Caspase
cascade
• Cytochrome
c
is
another
moonlightling
protein
61.
62. Mitochondrial
genes
• Circular
double
stranded
mtDNA
• Each
mito
has
~
5
copies
• Human
mt
genome
contains
37
genes:
13
encode
subunits
of
respiratory
chain
proteins
24
encode
for
tRNA
and
rRNA
• The
majority
of
mito’s
1100
proteins
are
encoded
by
nuclear
genes
and
translated
on
cytosolic
ribosomes
63. Muta*ons
in
mtDNA
accumulate
• Mito
are
exposed
the
most
to
ROS
• mtDNA
replica9on
and
repair
are
less
effec9ve
than
nuclear
DNA
replica9on
è
Defects
in
mtDNA
occur
over
8me
• Animals
inherit
their
mito
from
mothers
• 105-‐106
mito/egg
and
102-‐103
mito/
sperm.
Also
eggs
target
sperm
mito
for
degrada9on
• Heteroplasmy
and
homoplasmy
wt cells – blue
Mutant COX – brown
Different cells in the same tissue are
affected differently by mito mutation
64. Muta*ons
in
mtDNA
cause
disease
• Mitochondrial
encephalomyopathies
• affect
brain
and
skeletal
muscles
• Leber’s
hereditary
op*c
neuropathy
(LHON)
affects
the
central
nervous
system
(leads
to
loss
of
vision)
• Point
muta9on
in
mitochondrial
gene
ND4
à
mito
par9ally
defec9ve
in
electron
transfer
through
complex
I
• Mito
can
produce
ATP
from
complex
II
but
apparently
cannot
supply
enough
ATP
to
support
the
very
ac9ve
metabolism
of
neurons
à
damage
to
op9c
nerve
à
blindness
• Diabetes
• Defec9ve
OxPhos
in
pancrea9c
β
cells
blocks
insulin
secre9on
• In
normal
β
cells,
glc
is
taken
in
and
oxidized
to
raise
[ATP]
above
threshold.
ATP
blocks
K+
channel
à
depolariza9on
of
membrane
à
opening
of
voltage-‐gated
Ca2+
channels
à
Ca2+
influx
into
cytoplasm
leads
to
the
release
of
insulin
into
blood
65.
66. Ques*on
6
(Take
home
exam)
Due:
NEXT
WEEK
(js*ban@birzeit.edu)
• Please
solve
ques*ons:
1. 6
(uncouplers)
2. 17
(ATP
turnover)
3. 22
(alanine)
4. 24
(diabetes)
For
wriZen
answers,
I
prefer
to
have
them
typed
in
Word.
I
can
accept
the
assignment
in
one
file
sent
to
my
email.
For
answers
that
require
solving
mathema8cally,
you
can
either
type
them
or
write
them
down
and
scan
them.