Biochemistry involves the study of biomolecules like carbohydrates, proteins, lipids, and nucleic acids, as well as their structures, functions, and reactions in living systems. Bioenergetics is the study of energy transfer and utilization in living systems. It concerns the initial and final energy states of reactions irrespective of time. The change in Gibbs free energy (ΔG) is the main measure in bioenergetics, as it indicates the energetic feasibility of reactions and whether they will occur spontaneously. Living cells maintain homeostasis even when far from equilibrium by expending energy to increase order and releasing energy to increase entropy in the surroundings.
Gluconeogenesis is the process by which glucose is synthesized from non-carbohydrate precursors in the liver and kidneys. It is necessary because glucose demand exceeds what can be provided by glycogen stores alone. Gluconeogenesis uses some of the same enzymes as glycolysis but in the reverse direction and requires additional ATP and GTP to drive the energetically unfavorable reactions. Key regulatory steps include the conversion of pyruvate to oxaloacetate and phosphoenolpyruvate, which are controlled by pyruvate carboxylase and PEP carboxykinase. Fructose-2,6-bisphosphate plays a central role in regulating gluconeogenesis through its effects on glycoly
This document discusses bioenergetics and biochemical thermodynamics. It begins with an introduction to bioenergetics as the study of energy transformations that take place in living organisms. Energy is present in different forms and can be interconverted, with some forms being used to do work. Key concepts discussed include ATP as the "energy currency" of cells, oxidative phosphorylation, and the laws of thermodynamics. The document also covers topics like exergonic and endergonic reactions, Gibbs free energy, redox potentials, and high-energy compounds that store and release chemical energy like ATP.
The HMP shunt pathway, also known as the pentose phosphate pathway or phosphogluconate pathway, is an alternative metabolic pathway to glycolysis for glucose. It is more anabolic and produces NADPH and pentoses through oxidative and non-oxidative phases of reactions. The HMP shunt pathway is important for biosynthesis in tissues like the liver, testes, ovaries, and mammary glands. It provides reducing power in the form of NADPH for biosynthesis of fatty acids, cholesterol, and steroid hormones. NADPH also helps maintain red blood cell membrane integrity and protects against oxidative damage.
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This document discusses photosynthesis and cellular respiration. It outlines the key pigments involved in photosynthesis like chlorophyll a and b as well as carotenoids. It also describes the light and dark reactions of photosynthesis, including the cyclic and non-cyclic pathways. For cellular respiration, it distinguishes between aerobic and anaerobic respiration, listing lactic acid fermentation and alcoholic fermentation as types of anaerobic respiration. It further breaks down aerobic respiration into the preparatory, oxidative, and pyruvic acid oxidation phases and describes the citric acid cycle and respiratory chain.
- The document summarizes purine and pyrimidine nucleotide metabolism. It describes the biosynthesis and degradation pathways of purines and pyrimidines, and their regulation. Key enzymes and cofactors like tetrahydrofolate and PRPP are discussed.
- Inhibitors of nucleotide metabolism are important targets for cancer chemotherapy drugs. Drugs like methotrexate and fluorouracil inhibit key enzymes to selectively target rapidly dividing cancer cells.
- The metabolism of purines and pyrimidines provides the essential building blocks for nucleic acid synthesis and is tightly regulated through feedback inhibition at multiple steps in the pathways. Proper regulation is crucial as nucleotides are required for cell growth and proliferation.
This document provides an overview of enzymes and enzyme kinetics taught in the Principles of Biochemistry course (HFB324) by Dr. Siham Gritly. It defines key enzyme terms and concepts, describes enzyme classification systems, the components and localization of enzymes in the body, and models of enzyme catalysis including active sites and enzyme-substrate binding. It also explains Michaelis-Menten kinetics and how various factors influence the velocity of enzyme reactions such as substrate concentration, temperature, and inhibitors.
Metabolic pathways and energy production involve catabolic reactions that break down molecules and provide energy in the form of ATP. Glycolysis is the process by which glucose is converted to pyruvate through a series of reactions, generating a small amount of ATP. In aerobic conditions, pyruvate undergoes further reactions to form acetyl-CoA and enters the citric acid cycle, while in anaerobic conditions it is reduced to lactate. Coenzymes such as NAD+ and FAD help transfer hydrogen atoms between reactions and link metabolic pathways.
Gluconeogenesis is the process by which glucose is synthesized from non-carbohydrate precursors in the liver and kidneys. It is necessary because glucose demand exceeds what can be provided by glycogen stores alone. Gluconeogenesis uses some of the same enzymes as glycolysis but in the reverse direction and requires additional ATP and GTP to drive the energetically unfavorable reactions. Key regulatory steps include the conversion of pyruvate to oxaloacetate and phosphoenolpyruvate, which are controlled by pyruvate carboxylase and PEP carboxykinase. Fructose-2,6-bisphosphate plays a central role in regulating gluconeogenesis through its effects on glycoly
This document discusses bioenergetics and biochemical thermodynamics. It begins with an introduction to bioenergetics as the study of energy transformations that take place in living organisms. Energy is present in different forms and can be interconverted, with some forms being used to do work. Key concepts discussed include ATP as the "energy currency" of cells, oxidative phosphorylation, and the laws of thermodynamics. The document also covers topics like exergonic and endergonic reactions, Gibbs free energy, redox potentials, and high-energy compounds that store and release chemical energy like ATP.
The HMP shunt pathway, also known as the pentose phosphate pathway or phosphogluconate pathway, is an alternative metabolic pathway to glycolysis for glucose. It is more anabolic and produces NADPH and pentoses through oxidative and non-oxidative phases of reactions. The HMP shunt pathway is important for biosynthesis in tissues like the liver, testes, ovaries, and mammary glands. It provides reducing power in the form of NADPH for biosynthesis of fatty acids, cholesterol, and steroid hormones. NADPH also helps maintain red blood cell membrane integrity and protects against oxidative damage.
Join live classes, download study aids, sell your documents, join or host your own classes online, get tutoring, tutor students, take practices tests and more at Examville.com
This document discusses photosynthesis and cellular respiration. It outlines the key pigments involved in photosynthesis like chlorophyll a and b as well as carotenoids. It also describes the light and dark reactions of photosynthesis, including the cyclic and non-cyclic pathways. For cellular respiration, it distinguishes between aerobic and anaerobic respiration, listing lactic acid fermentation and alcoholic fermentation as types of anaerobic respiration. It further breaks down aerobic respiration into the preparatory, oxidative, and pyruvic acid oxidation phases and describes the citric acid cycle and respiratory chain.
- The document summarizes purine and pyrimidine nucleotide metabolism. It describes the biosynthesis and degradation pathways of purines and pyrimidines, and their regulation. Key enzymes and cofactors like tetrahydrofolate and PRPP are discussed.
- Inhibitors of nucleotide metabolism are important targets for cancer chemotherapy drugs. Drugs like methotrexate and fluorouracil inhibit key enzymes to selectively target rapidly dividing cancer cells.
- The metabolism of purines and pyrimidines provides the essential building blocks for nucleic acid synthesis and is tightly regulated through feedback inhibition at multiple steps in the pathways. Proper regulation is crucial as nucleotides are required for cell growth and proliferation.
This document provides an overview of enzymes and enzyme kinetics taught in the Principles of Biochemistry course (HFB324) by Dr. Siham Gritly. It defines key enzyme terms and concepts, describes enzyme classification systems, the components and localization of enzymes in the body, and models of enzyme catalysis including active sites and enzyme-substrate binding. It also explains Michaelis-Menten kinetics and how various factors influence the velocity of enzyme reactions such as substrate concentration, temperature, and inhibitors.
Metabolic pathways and energy production involve catabolic reactions that break down molecules and provide energy in the form of ATP. Glycolysis is the process by which glucose is converted to pyruvate through a series of reactions, generating a small amount of ATP. In aerobic conditions, pyruvate undergoes further reactions to form acetyl-CoA and enters the citric acid cycle, while in anaerobic conditions it is reduced to lactate. Coenzymes such as NAD+ and FAD help transfer hydrogen atoms between reactions and link metabolic pathways.
This document provides an overview of chapter 8 from Campbell Biology, 9th edition, which discusses metabolism. It covers several key topics in 3 paragraphs or less:
Metabolism transforms matter and energy according to the laws of thermodynamics through metabolic pathways mediated by enzymes. Catabolic pathways release energy by breaking down molecules, while anabolic pathways use energy to build molecules. ATP powers cellular work by coupling exergonic reactions to endergonic reactions.
Enzymes speed up metabolic reactions by lowering activation energy. Each enzyme has a specific substrate that binds at its active site, orienting the reactants in a way that facilitates the reaction. Environmental factors like temperature and pH can impact an enzyme's activity by influencing its
The document discusses metabolism of purine and pyrimidine bases and related disorders. It describes the de novo synthesis and salvage pathways of purines, involving enzymes like phosphoribosyl pyrophosphate, glutamine, and formyl-THF. Defects can cause increased purine production and degradation, leading to high uric acid levels and gout. The pyrimidine pathway is also summarized, involving carbamoyl phosphate, aspartate, orotic acid, and enzymes like thymidylate synthase. Certain cancers overexpress thymidylate synthase, making it a drug target. The document concludes by mentioning types of orotic aciduria due to defects in pyrimid
The document provides information on the genetic code and the process of translation. It defines the genetic code as the system of nucleotide sequences that designate amino acid sequences during translation. There are 3 key points:
1. The genetic code is universal, with some minor exceptions, where certain codons code for different amino acids in bacteria and mitochondrial DNA. It uses 64 possible triplet codon combinations of A, C, G, and U nucleotides to specify 20 amino acids.
2. Translation is the process by which the genetic code is read to produce proteins. It occurs via five stages - initiation, elongation, termination, and post-translational modification - involving messenger RNA, transfer RNA, ribosomes and other factors.
3
Bioenergetics is the study of energy transformations that occur in living cells. It examines how cells acquire chemical energy from nutrients and transform that energy to power biological processes through reactions like oxidative phosphorylation. Adenosine triphosphate (ATP) acts as the main energy currency, being produced from energy sources and broken down to release energy for cellular work. Thermodynamic principles like the first and second laws govern these energy transformations, requiring a constant total energy while increasing entropy as energy is dissipated into less useful forms like heat.
Nucleotide Biosynthesis involves 2 processes. one is Denovo synthesis and other is Salvage pathway. An outline of both the processes has given in this presentation.
1) Bioenergetics examines the energy flow in living organisms using concepts like entropy, enthalpy, and free energy.
2) ATP acts as the energy currency of cells, being produced through exergonic reactions and consumed to power endergonic reactions.
3) Standard free energy changes can be added for coupled reactions and actual free energy depends on reactant and product concentrations, driving reactions towards or away from equilibrium.
Glycolysis is the metabolic pathway that converts glucose into pyruvate, producing ATP and NADH in the process. It is an ancient and nearly universal pathway that occurs in the cytosol of cells. Glycolysis consists of two phases - the preparatory phase in which ATP is consumed to modify glucose, and the payoff phase in which net ATP is produced. Key steps include phosphorylation of glucose, isomerization to fructose, and cleavage and rearrangement to two trioses. This yields two pyruvate molecules, two ATP, and two NADH from each glucose. Glycolysis is highly regulated and crucial for energy production in most organisms.
This document discusses the biosynthesis of purines and pyrimidines. It explains that purines and pyrimidines are synthesized through de novo and salvage pathways. The de novo pathway involves multiple enzyme-catalyzed steps to convert simple precursors into the complex purine and pyrimidine nucleotides. This includes converting ribose-5-phosphate into inosine monophosphate (IMP) through 10 steps for purine synthesis. IMP is then used to synthesize adenine monophosphate (AMP) and guanine monophosphate (GMP). The salvage pathway recovers bases and nucleotides from degraded DNA and RNA. Pyrimidine synthesis is described as simpler than purine synthesis.
Biological oxidation Bioenergetics and general concepts (part - I)Ashok Katta
The document discusses biochemical thermodynamics and energy transformations that occur in living systems. It explains that biochemical thermodynamics deals with the energy changes in biochemical reactions and predicts whether processes are possible, while kinetics measures reaction rates. The first and second laws of thermodynamics are described, with the first law stating that energy cannot be created or destroyed, only converted between forms, and the second law stating that spontaneous reactions result in increased disorder. ATP is discussed as the major carrier of chemical energy in cells, with its hydrolysis being an exergonic reaction and synthesis being endergonic. Substrate-level phosphorylation and electron transport chain are described as mechanisms for generating ATP.
The document summarizes the process of glycogenesis, or the synthesis of glycogen from glucose. It involves multiple enzymatic steps: (1) glucose is converted to glucose-6-phosphate then glucose-1-phosphate, (2) UDP-glucose is synthesized from glucose-1-phosphate and UTP, (3) a small fragment of existing glycogen acts as a primer, with the initial glucose attached to glycogenin by glycogen initiator synthase, (4) glycogen synthase elongates the primer by adding glucose units with alpha-1,4 linkages, while glucosyl-4,6 transferase introduces alpha-1,6 branch linkages, building the glycogen molecule.
Bioenergetics is the study of energy in living systems and how organisms utilize energy. All organisms require energy, which can be in kinetic or potential forms. Bioenergetics examines how organisms harness energy through metabolic pathways and chemical reactions, breaking and forming chemical bonds to facilitate biological processes like growth. A key part of bioenergetics is how ATP serves as the "energy currency" of cells, being produced through cellular respiration and allowing energy transfer for various reactions. The laws of thermodynamics also govern energy transformations in biological systems.
Enzymes properties, nomenclature and classificationJasmineJuliet
Enzymes - Definition, Introduction about biocatalysts, Properties of enzymes, Specificity, capacity for regulation, Example for enzyme at specific pH, Nomenclature of enzymes, Systematic name, common name, enzyme commission number, Classification of enzymes: Oxidoreductase, Transferase, lyases, ligases, isomerases, hydrolases.
Bioenergetics is the study of energy changes in biochemical reactions and biological systems. The laws of thermodynamics govern energy changes. ATP is the primary energy currency in cells. It is produced through oxidative phosphorylation where the energy released from redox reactions is used to pump protons across the mitochondrial inner membrane, creating a proton gradient. ATP synthase uses this proton gradient to phosphorylate ADP, producing ATP. Diseases can result from defects in the electron transport chain or oxidative phosphorylation.
Bioenergetics deals with energy changes in biochemical reactions, specifically the initial and final energy states without considering mechanisms. Energy rich compounds store energy that can be released, such as ATP which contains energy in its phosphate bonds and is used universally in metabolism. Cyclic AMP is synthesized from ATP by adenyl cyclase and acts as a second messenger in intracellular signal transduction such as regulating metabolism.
This document discusses glycogen metabolism. It notes that glycogen is a readily available form of glucose storage found primarily in the liver and muscles. Glycogen synthesis, or glycogenesis, occurs in the fed state in these tissues and involves three steps - isomerization of glucose-6-phosphate to glucose-1-phosphate, activation of glucose-1-phosphate to UDP-glucose, and linkage of UDP-glucose to a glycogen chain catalyzed by glycogen synthase. Glycogen branching is accomplished by the enzyme amylo-(1,4-1,6)-trans-glycosylase which transfers glycogen segments to form branches. The synthesis and breakdown of glycogen in the liver and muscles
A comprehensive presentation on Enzymology :Types of Enzyme inhibition & Therapeutic uses for MBBS ,BDS, B Pharm & Biotechnology students to facilitate self- study.
Lineweaver - Burk Plot accurate determination of VmaxAkhil Pradeep
The document discusses Lineweaver-Burk plots, which were developed by Hans Lineweaver and Dean Burk as a more accurate way to determine the maximum velocity (Vmax) of an enzyme-catalyzed reaction compared to Michaelis-Menten curves. It also describes different types of enzyme inhibition including competitive, uncompetitive, and non-competitive inhibition and how they affect the kinetics. Allosteric enzymes are discussed as having sigmoidal curves rather than hyperbolic curves due to binding of molecules at allosteric sites that can activate or inhibit the enzyme.
B.sc. biochemistry sem 1 introduction to biochemistry unit 4 metabolism and b...Rai University
The document discusses metabolic concepts and bioenergetics. It explains that metabolism occurs through enzyme-catalyzed reactions in metabolic pathways. Catabolic pathways break down nutrients into smaller molecules and release energy as ATP or electron carriers, while anabolic pathways use this energy to build larger molecules. The two laws of thermodynamics state that energy is conserved but tends towards increased entropy. Mitochondria allow catabolism of glucose to release energy through three main stages - glycolysis outside the mitochondria yields some ATP, the Krebs cycle in the matrix yields more ATP, and electron transport inside the cristae yields the most ATP by pumping protons and producing ATP synthase. Overall, breaking down one glucose molecule yields about 36 ATP.
The document summarizes key topics in biochemistry including metabolism, bioenergetics, and biochemical pathways. Specifically, it discusses [1] the principles of bioenergetics including thermodynamics, phosphoryl group transfers, and oxidation-reduction reactions; [2] how ATP and other phosphorylated compounds are used to drive cellular processes; and [3] how electrons flow through metabolic pathways and soluble electron carriers to provide energy for biological work. It concludes by outlining topics to be covered in the next chapter on glycolysis and carbohydrate catabolism.
The document summarizes electron transport and oxidative phosphorylation. It describes how electrons from NADH and FADH2 are transported via carriers in the mitochondrial electron transport system to oxygen, with energy released used to synthesize ATP. Protons are pumped from the mitochondrial matrix to the intermembrane space, building a proton gradient that drives ATP synthesis by ATP synthase as protons flow back into the matrix. This chemiosmotic coupling allows efficient conversion of electron potential energy to chemical energy in the form of ATP.
This presentation is about bioenergetics. It talks about energy changes and equilibrium during different biological reactions, how exergonic and endergonic reactions are combined as sequential reactions in body, how the body system is following the law of thermodynamics etc. Role of enzymes in thermodynamics is also explained
The study of energy in living systems (environments) and the organisms (plants and animals) that utilize them.
I'm a st.Xavier's student . i think this ppt will be helpful to the others. Because this is needed in our daily life.
This document provides an overview of chapter 8 from Campbell Biology, 9th edition, which discusses metabolism. It covers several key topics in 3 paragraphs or less:
Metabolism transforms matter and energy according to the laws of thermodynamics through metabolic pathways mediated by enzymes. Catabolic pathways release energy by breaking down molecules, while anabolic pathways use energy to build molecules. ATP powers cellular work by coupling exergonic reactions to endergonic reactions.
Enzymes speed up metabolic reactions by lowering activation energy. Each enzyme has a specific substrate that binds at its active site, orienting the reactants in a way that facilitates the reaction. Environmental factors like temperature and pH can impact an enzyme's activity by influencing its
The document discusses metabolism of purine and pyrimidine bases and related disorders. It describes the de novo synthesis and salvage pathways of purines, involving enzymes like phosphoribosyl pyrophosphate, glutamine, and formyl-THF. Defects can cause increased purine production and degradation, leading to high uric acid levels and gout. The pyrimidine pathway is also summarized, involving carbamoyl phosphate, aspartate, orotic acid, and enzymes like thymidylate synthase. Certain cancers overexpress thymidylate synthase, making it a drug target. The document concludes by mentioning types of orotic aciduria due to defects in pyrimid
The document provides information on the genetic code and the process of translation. It defines the genetic code as the system of nucleotide sequences that designate amino acid sequences during translation. There are 3 key points:
1. The genetic code is universal, with some minor exceptions, where certain codons code for different amino acids in bacteria and mitochondrial DNA. It uses 64 possible triplet codon combinations of A, C, G, and U nucleotides to specify 20 amino acids.
2. Translation is the process by which the genetic code is read to produce proteins. It occurs via five stages - initiation, elongation, termination, and post-translational modification - involving messenger RNA, transfer RNA, ribosomes and other factors.
3
Bioenergetics is the study of energy transformations that occur in living cells. It examines how cells acquire chemical energy from nutrients and transform that energy to power biological processes through reactions like oxidative phosphorylation. Adenosine triphosphate (ATP) acts as the main energy currency, being produced from energy sources and broken down to release energy for cellular work. Thermodynamic principles like the first and second laws govern these energy transformations, requiring a constant total energy while increasing entropy as energy is dissipated into less useful forms like heat.
Nucleotide Biosynthesis involves 2 processes. one is Denovo synthesis and other is Salvage pathway. An outline of both the processes has given in this presentation.
1) Bioenergetics examines the energy flow in living organisms using concepts like entropy, enthalpy, and free energy.
2) ATP acts as the energy currency of cells, being produced through exergonic reactions and consumed to power endergonic reactions.
3) Standard free energy changes can be added for coupled reactions and actual free energy depends on reactant and product concentrations, driving reactions towards or away from equilibrium.
Glycolysis is the metabolic pathway that converts glucose into pyruvate, producing ATP and NADH in the process. It is an ancient and nearly universal pathway that occurs in the cytosol of cells. Glycolysis consists of two phases - the preparatory phase in which ATP is consumed to modify glucose, and the payoff phase in which net ATP is produced. Key steps include phosphorylation of glucose, isomerization to fructose, and cleavage and rearrangement to two trioses. This yields two pyruvate molecules, two ATP, and two NADH from each glucose. Glycolysis is highly regulated and crucial for energy production in most organisms.
This document discusses the biosynthesis of purines and pyrimidines. It explains that purines and pyrimidines are synthesized through de novo and salvage pathways. The de novo pathway involves multiple enzyme-catalyzed steps to convert simple precursors into the complex purine and pyrimidine nucleotides. This includes converting ribose-5-phosphate into inosine monophosphate (IMP) through 10 steps for purine synthesis. IMP is then used to synthesize adenine monophosphate (AMP) and guanine monophosphate (GMP). The salvage pathway recovers bases and nucleotides from degraded DNA and RNA. Pyrimidine synthesis is described as simpler than purine synthesis.
Biological oxidation Bioenergetics and general concepts (part - I)Ashok Katta
The document discusses biochemical thermodynamics and energy transformations that occur in living systems. It explains that biochemical thermodynamics deals with the energy changes in biochemical reactions and predicts whether processes are possible, while kinetics measures reaction rates. The first and second laws of thermodynamics are described, with the first law stating that energy cannot be created or destroyed, only converted between forms, and the second law stating that spontaneous reactions result in increased disorder. ATP is discussed as the major carrier of chemical energy in cells, with its hydrolysis being an exergonic reaction and synthesis being endergonic. Substrate-level phosphorylation and electron transport chain are described as mechanisms for generating ATP.
The document summarizes the process of glycogenesis, or the synthesis of glycogen from glucose. It involves multiple enzymatic steps: (1) glucose is converted to glucose-6-phosphate then glucose-1-phosphate, (2) UDP-glucose is synthesized from glucose-1-phosphate and UTP, (3) a small fragment of existing glycogen acts as a primer, with the initial glucose attached to glycogenin by glycogen initiator synthase, (4) glycogen synthase elongates the primer by adding glucose units with alpha-1,4 linkages, while glucosyl-4,6 transferase introduces alpha-1,6 branch linkages, building the glycogen molecule.
Bioenergetics is the study of energy in living systems and how organisms utilize energy. All organisms require energy, which can be in kinetic or potential forms. Bioenergetics examines how organisms harness energy through metabolic pathways and chemical reactions, breaking and forming chemical bonds to facilitate biological processes like growth. A key part of bioenergetics is how ATP serves as the "energy currency" of cells, being produced through cellular respiration and allowing energy transfer for various reactions. The laws of thermodynamics also govern energy transformations in biological systems.
Enzymes properties, nomenclature and classificationJasmineJuliet
Enzymes - Definition, Introduction about biocatalysts, Properties of enzymes, Specificity, capacity for regulation, Example for enzyme at specific pH, Nomenclature of enzymes, Systematic name, common name, enzyme commission number, Classification of enzymes: Oxidoreductase, Transferase, lyases, ligases, isomerases, hydrolases.
Bioenergetics is the study of energy changes in biochemical reactions and biological systems. The laws of thermodynamics govern energy changes. ATP is the primary energy currency in cells. It is produced through oxidative phosphorylation where the energy released from redox reactions is used to pump protons across the mitochondrial inner membrane, creating a proton gradient. ATP synthase uses this proton gradient to phosphorylate ADP, producing ATP. Diseases can result from defects in the electron transport chain or oxidative phosphorylation.
Bioenergetics deals with energy changes in biochemical reactions, specifically the initial and final energy states without considering mechanisms. Energy rich compounds store energy that can be released, such as ATP which contains energy in its phosphate bonds and is used universally in metabolism. Cyclic AMP is synthesized from ATP by adenyl cyclase and acts as a second messenger in intracellular signal transduction such as regulating metabolism.
This document discusses glycogen metabolism. It notes that glycogen is a readily available form of glucose storage found primarily in the liver and muscles. Glycogen synthesis, or glycogenesis, occurs in the fed state in these tissues and involves three steps - isomerization of glucose-6-phosphate to glucose-1-phosphate, activation of glucose-1-phosphate to UDP-glucose, and linkage of UDP-glucose to a glycogen chain catalyzed by glycogen synthase. Glycogen branching is accomplished by the enzyme amylo-(1,4-1,6)-trans-glycosylase which transfers glycogen segments to form branches. The synthesis and breakdown of glycogen in the liver and muscles
A comprehensive presentation on Enzymology :Types of Enzyme inhibition & Therapeutic uses for MBBS ,BDS, B Pharm & Biotechnology students to facilitate self- study.
Lineweaver - Burk Plot accurate determination of VmaxAkhil Pradeep
The document discusses Lineweaver-Burk plots, which were developed by Hans Lineweaver and Dean Burk as a more accurate way to determine the maximum velocity (Vmax) of an enzyme-catalyzed reaction compared to Michaelis-Menten curves. It also describes different types of enzyme inhibition including competitive, uncompetitive, and non-competitive inhibition and how they affect the kinetics. Allosteric enzymes are discussed as having sigmoidal curves rather than hyperbolic curves due to binding of molecules at allosteric sites that can activate or inhibit the enzyme.
B.sc. biochemistry sem 1 introduction to biochemistry unit 4 metabolism and b...Rai University
The document discusses metabolic concepts and bioenergetics. It explains that metabolism occurs through enzyme-catalyzed reactions in metabolic pathways. Catabolic pathways break down nutrients into smaller molecules and release energy as ATP or electron carriers, while anabolic pathways use this energy to build larger molecules. The two laws of thermodynamics state that energy is conserved but tends towards increased entropy. Mitochondria allow catabolism of glucose to release energy through three main stages - glycolysis outside the mitochondria yields some ATP, the Krebs cycle in the matrix yields more ATP, and electron transport inside the cristae yields the most ATP by pumping protons and producing ATP synthase. Overall, breaking down one glucose molecule yields about 36 ATP.
The document summarizes key topics in biochemistry including metabolism, bioenergetics, and biochemical pathways. Specifically, it discusses [1] the principles of bioenergetics including thermodynamics, phosphoryl group transfers, and oxidation-reduction reactions; [2] how ATP and other phosphorylated compounds are used to drive cellular processes; and [3] how electrons flow through metabolic pathways and soluble electron carriers to provide energy for biological work. It concludes by outlining topics to be covered in the next chapter on glycolysis and carbohydrate catabolism.
The document summarizes electron transport and oxidative phosphorylation. It describes how electrons from NADH and FADH2 are transported via carriers in the mitochondrial electron transport system to oxygen, with energy released used to synthesize ATP. Protons are pumped from the mitochondrial matrix to the intermembrane space, building a proton gradient that drives ATP synthesis by ATP synthase as protons flow back into the matrix. This chemiosmotic coupling allows efficient conversion of electron potential energy to chemical energy in the form of ATP.
This presentation is about bioenergetics. It talks about energy changes and equilibrium during different biological reactions, how exergonic and endergonic reactions are combined as sequential reactions in body, how the body system is following the law of thermodynamics etc. Role of enzymes in thermodynamics is also explained
The study of energy in living systems (environments) and the organisms (plants and animals) that utilize them.
I'm a st.Xavier's student . i think this ppt will be helpful to the others. Because this is needed in our daily life.
BCM 201_Energetics of life and the functioning of living organismspetshelter54
The document provides an overview of energetics in life processes. It discusses how organisms harvest energy from food sources like carbohydrates, lipids, and proteins through metabolic pathways. Cellular respiration involves glycolysis, the Krebs cycle, and the electron transport chain to break down glucose and generate ATP. ATP is the primary energy currency that powers cellular activities. While some reactions generate energy, others require energy input to drive unfavorable reactions. Metabolic pathways evolve through coupling of reactions.
Metabolism involves anabolic and catabolic pathways that build up or break down molecules. These pathways are coupled so that energy released in catabolism can drive energy-requiring anabolism. Thermodynamics studies energy transformations, with the first law stating energy is conserved and the second law that entropy always increases. Free energy indicates what reactions are spontaneous as it decreases for such reactions, allowing maximal work. Metabolism maintains order by using exergonic reactions to power endergonic ones, keeping cells from equilibrium and alive.
Metabolism refers to the chemical processes that take place inside cells, including thousands of reactions that build up or break down complex compounds. These anabolic and catabolic pathways are concerned with managing the cell's energy and resources. Metabolism involves the conversion of energy from one form to another, as governed by the laws of thermodynamics. ATP acts as the main energy currency, using energy released from its phosphate bonds to power cellular work through exergonic reactions. Enzymes are crucial to metabolism as they catalyze reactions and allow them to proceed faster by lowering their activation energy. Metabolic pathways are regulated through feedback inhibition which turns pathways off once a threshold of end products has been reached.
KEY CONCEPTS
8.1 An organism’s metabolism transforms matter and
energy, subject to the laws of thermodynamics
8.2 The free-energy change of a reaction tells us whether or not the reaction occurs
spontaneously
8.3 ATP powers cellular work by coupling exergonic reactions to endergonic reactions
8.4 Enzymes speed up metabolic reactions by lowering energy barriers
8.5 Regulation of enzyme activity helps control metabolism
This document provides an overview of metabolism and bioenergetics. It discusses how cells extract energy from reactions to perform work, and how metabolism involves thousands of chemical reactions catalyzed by enzymes. Metabolic pathways convert molecules through a series of steps, with catabolic pathways releasing energy and anabolic pathways requiring energy. The energy of reactions is discussed in terms of free energy, and how ATP powers cellular work by coupling exergonic reactions to endergonic processes through phosphorylation. Enzymes lower the activation energy of reactions to speed up metabolism.
Metabolism is the set of chemical reactions that occur in living organisms to sustain life. Energy from food fuels these reactions through the intermediary ATP. Enzymes catalyze reactions by lowering their activation energy. Regulation of enzyme activity controls metabolic pathways and maintains cellular homeostasis.
Concept of Energy and Bioenergetics.pptxNawangSherpa6
Bioenergetics is the study of the transformation of energy in living organisms. It focuses on how cells convert energy from one form to another and how this energy supports biological processes.
This document discusses bioenergetics and the laws of thermodynamics. It defines bioenergetics as the quantitative study of energy transduction in living cells, including the release, storage, and use of energy along with the chemical processes underlying these changes. It describes the first and second laws of thermodynamics and how living systems are open systems that exchange both material and energy with their surroundings. It also discusses concepts like Gibbs free energy, entropy, and how cells couple endergonic reactions to exergonic ones through ATP to drive cellular processes.
This document discusses bioenergetics and the role of ATP in living systems. It explains that ATP stores and transports chemical energy within cells, which is released through its hydrolysis into ADP and phosphate. The hydrolysis of ATP is highly exergonic, with a large negative standard free energy change of -30.5 kJ/mol. This energy from ATP hydrolysis drives endergonic biochemical reactions and processes, such as the synthesis of glucose-6-phosphate from glucose and phosphate. The energy from ATP hydrolysis is efficiently coupled to these endergonic reactions through a cyclic process of ATP synthesis and breakdown.
1. Metabolism transforms matter and energy through chemical reactions within organisms, subject to the laws of thermodynamics. 2. Metabolic pathways are organized into catabolic pathways that break down molecules and release energy, and anabolic pathways that use energy to build molecules. 3. ATP powers cellular work by coupling exergonic reactions like its own hydrolysis to drive endergonic reactions like protein synthesis.
1. Essentials of thermodynamics-1.pptx BSNshahbazsahbi8
This document discusses key concepts in thermodynamics and their applications in biophysics. It introduces biophysics as applying physics principles to biological systems. Thermodynamics provides a framework to understand energy transformations in living organisms. The three laws of thermodynamics - zeroth law regarding thermal equilibrium, first law of energy conservation, and second law of entropy increase - are explained. The third law is also introduced. Examples are given of how these laws apply to biological processes like cellular respiration, protein folding, and temperature regulation. Biological thermodynamics is defined as studying biochemical dynamics controlled by energy processes like ATP hydrolysis and enzyme kinetics.
This document provides an overview of metabolism and oxidative phosphorylation. It defines oxidative phosphorylation as the formation of ATP using energy released by electron transfer through electron carriers in the mitochondrial inner membrane. A proton gradient couples ATP formation to electron transfer. Catabolic pathways break down molecules and release energy, while anabolic pathways use energy to build molecules. ATP powers cellular work by coupling exergonic reactions that release energy to endergonic reactions that require energy. Enzymes lower the activation energy of reactions and increase their rates.
1) Bioenergetics is the quantitative study of energy transduction and storage in living cells, along with the chemical processes underlying energy changes.
2) The first law of thermodynamics states that energy is conserved, while the second law states that entropy increases over time as energy spreads out.
3) Living organisms are open systems that maintain internal order by taking in free energy from nutrients or sunlight and releasing entropy as heat to the environment.
Energy and metabolism conduction,convection,radiation by Muhammad Fahad Ansar...fahadansari131
Insulation is not a method of heat transfer. It works by preventing heat transfer.
The particles in a solid are closest together.
Heat from the Sun reaches Earth through radiation, as there is no matter between the two for conduction or convection to occur.
A shiny surface, whether white or black, is best for reflecting heat radiation. Dull black is best for absorbing heat radiation.
Glycolysis is the pathway by which cells break down glucose to extract energy. Glucose first undergoes phosphorylation by hexokinase to form glucose-6-phosphate. A series of enzymatic reactions then convert glucose-6-phosphate through intermediates like fructose-6-phosphate and glyceraldehyde-3-phosphate, extracting energy in the form of ATP. Key steps include substrate-level phosphorylation by phosphofructokinase-1 and oxidation of glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate, reducing NAD+ to NADH. The pathway ultimately forms two pyruvate molecules from each glucose.
This document discusses glycogen metabolism. It notes that glycogen is the major storage carbohydrate in animals, found mainly in the liver and skeletal muscle. Glycogen is a branched polymer of glucose that is synthesized from glucose-1-phosphate via glycogen synthase. It can be broken down to glucose-1-phosphate by glycogen phosphorylase to maintain blood glucose levels. The activities of glycogen synthase and phosphorylase are regulated by phosphorylation and dephosphorylation in response to hormones like insulin and glucagon to control glycogen synthesis and breakdown.
Nucleic acids are polymers made of nucleotides that serve as the repository of genetic information. There are two main types of nucleic acids: DNA and RNA. DNA is found in cell nuclei and contains the genetic blueprint. RNA is found throughout the cell and assists in protein synthesis. A nucleotide contains a nitrogenous base (purine or pyrimidine), a 5-carbon sugar (deoxyribose in DNA and ribose in RNA), and one or more phosphate groups. Nucleotides bond together via phosphodiester linkages between the sugar and phosphate to form polynucleotide chains. DNA exists as a double helix with the bases on the inside bonded via hydrogen bonds in a complementary and antiparallel fashion
Enzymes are biological catalysts that are essential for life. They catalyze biochemical reactions efficiently and selectively. Enzymes lower the activation energy of reactions, increasing their rate. Most enzymes are proteins that use their tertiary structure and amino acid residues within their active site to catalyze reactions. The active site facilitates reactions by bringing substrates close together, stabilizing transition states, and using mechanisms like acid-base catalysis. This allows reactions to proceed rapidly under mild biological conditions. Without enzymes, reactions in living organisms would not occur at a useful pace to sustain life.
This document provides information on connective tissues. It discusses that connective tissue supports and surrounds other tissues, and is composed mainly of extracellular matrix secreted by connective tissue cells. The main components of connective tissue are cells, fibers, and ground substance. Connective tissues are classified as connective tissue proper (loose and dense connective tissues) or specialized connective tissues (including adipose, blood, cartilage, bone, and lymphoid tissues).
This document discusses nucleotides, nucleic acids, DNA and RNA. It begins by explaining that nucleic acids are made up of nucleotides, and the two main nucleic acids are RNA and DNA. It then discusses the structures and functions of nucleotides, nucleosides and nucleotides. Some key points include that nucleotides serve as energy carriers in cells and are components of coenzymes. The document also covers nitrogenous bases, purines and pyrimidines found in nucleic acids. It discusses how nucleotides join to form polynucleotides like DNA and RNA. In summary, the document provides an in-depth overview of the structures and roles of nucleotides, nucleic acids, DNA and RNA in the cell.
Nucleic acids are made up of nucleotides that contain nitrogenous bases, a 5-carbon sugar (ribose in RNA and deoxyribose in DNA), and phosphate groups. Nucleotides polymerize to form either RNA or DNA, which contain the genetic material in cells. The two strands of the DNA double helix are held together through hydrogen bonding between complementary nucleotide base pairs (A-T and G-C). This discovery explained how genetic information is stored and replicated in the stable double helical structure of DNA.
The document discusses insulin, describing its structure as a peptide hormone composed of two chains of amino acids linked by disulfide bridges that is produced in the beta cells of the pancreas. It explains insulin's role in regulating blood glucose levels through mechanisms like stimulating glucose uptake into cells and promoting the synthesis of enzymes involved in glucose metabolism. The summary also outlines insulin's synthesis, storage, and the factors that stimulate and inhibit its secretion.
The document discusses insulin, describing its structure as a peptide hormone composed of two chains of amino acids linked by disulfide bridges that is produced in the beta cells of the pancreas. It explains insulin's role in regulating blood glucose levels through mechanisms like stimulating glucose uptake into cells and promoting the synthesis of enzymes involved in glucose metabolism. The summary also outlines insulin's synthesis, storage, and the factors that stimulate and inhibit its secretion.
The skin is the largest organ and its health plays a vital role among the other sense organs. The skin concerns like acne breakout, psoriasis, or anything similar along the lines, finding a qualified and experienced dermatologist becomes paramount.
Osvaldo Bernardo Muchanga-GASTROINTESTINAL INFECTIONS AND GASTRITIS-2024.pdfOsvaldo Bernardo Muchanga
GASTROINTESTINAL INFECTIONS AND GASTRITIS
Osvaldo Bernardo Muchanga
Gastrointestinal Infections
GASTROINTESTINAL INFECTIONS result from the ingestion of pathogens that cause infections at the level of this tract, generally being transmitted by food, water and hands contaminated by microorganisms such as E. coli, Salmonella, Shigella, Vibrio cholerae, Campylobacter, Staphylococcus, Rotavirus among others that are generally contained in feces, thus configuring a FECAL-ORAL type of transmission.
Among the factors that lead to the occurrence of gastrointestinal infections are the hygienic and sanitary deficiencies that characterize our markets and other places where raw or cooked food is sold, poor environmental sanitation in communities, deficiencies in water treatment (or in the process of its plumbing), risky hygienic-sanitary habits (not washing hands after major and/or minor needs), among others.
These are generally consequences (signs and symptoms) resulting from gastrointestinal infections: diarrhea, vomiting, fever and malaise, among others.
The treatment consists of replacing lost liquids and electrolytes (drinking drinking water and other recommended liquids, including consumption of juicy fruits such as papayas, apples, pears, among others that contain water in their composition).
To prevent this, it is necessary to promote health education, improve the hygienic-sanitary conditions of markets and communities in general as a way of promoting, preserving and prolonging PUBLIC HEALTH.
Gastritis and Gastric Health
Gastric Health is one of the most relevant concerns in human health, with gastrointestinal infections being among the main illnesses that affect humans.
Among gastric problems, we have GASTRITIS AND GASTRIC ULCERS as the main public health problems. Gastritis and gastric ulcers normally result from inflammation and corrosion of the walls of the stomach (gastric mucosa) and are generally associated (caused) by the bacterium Helicobacter pylor, which, according to the literature, this bacterium settles on these walls (of the stomach) and starts to release urease that ends up altering the normal pH of the stomach (acid), which leads to inflammation and corrosion of the mucous membranes and consequent gastritis or ulcers, respectively.
In addition to bacterial infections, gastritis and gastric ulcers are associated with several factors, with emphasis on prolonged fasting, chemical substances including drugs, alcohol, foods with strong seasonings including chilli, which ends up causing inflammation of the stomach walls and/or corrosion. of the same, resulting in the appearance of wounds and consequent gastritis or ulcers, respectively.
Among patients with gastritis and/or ulcers, one of the dilemmas is associated with the foods to consume in order to minimize the sensation of pain and discomfort.
Travel vaccination in Manchester offers comprehensive immunization services for individuals planning international trips. Expert healthcare providers administer vaccines tailored to your destination, ensuring you stay protected against various diseases. Conveniently located clinics and flexible appointment options make it easy to get the necessary shots before your journey. Stay healthy and travel with confidence by getting vaccinated in Manchester. Visit us: www.nxhealthcare.co.uk
PGx Analysis in VarSeq: A User’s PerspectiveGolden Helix
Since our release of the PGx capabilities in VarSeq, we’ve had a few months to gather some insights from various use cases. Some users approach PGx workflows by means of array genotyping or what seems to be a growing trend of adding the star allele calling to the existing NGS pipeline for whole genome data. Luckily, both approaches are supported with the VarSeq software platform. The genotyping method being used will also dictate what the scope of the tertiary analysis will be. For example, are your PGx reports a standalone pipeline or would your lab’s goal be to handle a dual-purpose workflow and report on PGx + Diagnostic findings.
The purpose of this webcast is to:
Discuss and demonstrate the approaches with array and NGS genotyping methods for star allele calling to prep for downstream analysis.
Following genotyping, explore alternative tertiary workflow concepts in VarSeq to handle PGx reporting.
Moreover, we will include insights users will need to consider when validating their PGx workflow for all possible star alleles and options you have for automating your PGx analysis for large number of samples. Please join us for a session dedicated to the application of star allele genotyping and subsequent PGx workflows in our VarSeq software.
“Psychiatry and the Humanities”: An Innovative Course at the University of Mo...Université de Montréal
“Psychiatry and the Humanities”: An Innovative Course at the University of Montreal Expanding the medical model to embrace the humanities. Link: https://www.psychiatrictimes.com/view/-psychiatry-and-the-humanities-an-innovative-course-at-the-university-of-montreal
Computer in pharmaceutical research and development-Mpharm(Pharmaceutics)MuskanShingari
Statistics- Statistics is the science of collecting, organizing, presenting, analyzing and interpreting numerical data to assist in making more effective decisions.
A statistics is a measure which is used to estimate the population parameter
Parameters-It is used to describe the properties of an entire population.
Examples-Measures of central tendency Dispersion, Variance, Standard Deviation (SD), Absolute Error, Mean Absolute Error (MAE), Eigen Value
- Video recording of this lecture in English language: https://youtu.be/Pt1nA32sdHQ
- Video recording of this lecture in Arabic language: https://youtu.be/uFdc9F0rlP0
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
Histololgy of Female Reproductive System.pptxAyeshaZaid1
Dive into an in-depth exploration of the histological structure of female reproductive system with this comprehensive lecture. Presented by Dr. Ayesha Irfan, Assistant Professor of Anatomy, this presentation covers the Gross anatomy and functional histology of the female reproductive organs. Ideal for students, educators, and anyone interested in medical science, this lecture provides clear explanations, detailed diagrams, and valuable insights into female reproductive system. Enhance your knowledge and understanding of this essential aspect of human biology.
These lecture slides, by Dr Sidra Arshad, offer a simplified look into the mechanisms involved in the regulation of respiration:
Learning objectives:
1. Describe the organisation of respiratory center
2. Describe the nervous control of inspiration and respiratory rhythm
3. Describe the functions of the dorsal and respiratory groups of neurons
4. Describe the influences of the Pneumotaxic and Apneustic centers
5. Explain the role of Hering-Breur inflation reflex in regulation of inspiration
6. Explain the role of central chemoreceptors in regulation of respiration
7. Explain the role of peripheral chemoreceptors in regulation of respiration
8. Explain the regulation of respiration during exercise
9. Integrate the respiratory regulatory mechanisms
10. Describe the Cheyne-Stokes breathing
Study Resources:
1. Chapter 42, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 36, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 13, Human Physiology by Lauralee Sherwood, 9th edition
Discover the benefits of homeopathic medicine for irregular periods with our guide on 5 common remedies. Learn how these natural treatments can help regulate menstrual cycles and improve overall menstrual health.
Visit Us: https://drdeepikashomeopathy.com/service/irregular-periods-treatment/
NAVIGATING THE HORIZONS OF TIME LAPSE EMBRYO MONITORING.pdfRahul Sen
Time-lapse embryo monitoring is an advanced imaging technique used in IVF to continuously observe embryo development. It captures high-resolution images at regular intervals, allowing embryologists to select the most viable embryos for transfer based on detailed growth patterns. This technology enhances embryo selection, potentially increasing pregnancy success rates.
5. • Order is expensive
–Its existence is an active process
–It is an unnatural state of affairs
–If left to its devices nature will favor disorder
• An unattended environment will overtime become messy but it
wont suddenly become neat
6.
7.
8. • Equilibrium is not a prerequisite for homeostasis
• There are many examples of in living organisms of homeostasis existing when
state of affairs is far from equilibrium
• Energy is spent to pay for the decrease in entropy of the system
9.
10.
11.
12. Bioenergetics
• Is a field of biochemistry dealing with the transfer
and utilization of energy in living systems
13. Bioenergetics
• The study of bioenergetics concerns the initial and the final energy
states of a reaction irrespective of the time it takes to go from
reactants to products
• Free energy AKA Gibbs free energy (G): That portion of the energy of a
system available to do work as the system proceeds toward
equilibrium under conditions of constant temperature and pressure
• Change in Gibbs free energy (ΔG) is the main measure in bioenergetics
– It is a measure of the energetic feasibility of a reaction and allows a prediction
of whether or not the reaction will take place
14. Why study Bioenergetics
• Living organisms must perform work to stay alive, to grow and to
reproduce. The metabolic processes through which living organisms
accomplish these tasks utilize energy/involve energy transactions
• Hence the rationale for the ability of living organisms to harness energy
and to channel it into biological work (metabolism) as a fundamental
requirement for life
• Metabolism (vital for life) entails the chemical transformations taking place
in a cell or an organism
– Occurs through series/cascades of enzyme catalyzed reactions, referred to as
metabolic pathways
• Interconversion of metabolites, Catabolism and Anabolism
15. Why study Bioenergetics!
• Living organisms carry out a remarkable variety of
energy conversions from one form to another
• The chemical energy in fuels is used to bring about the
synthesis of complex macromolecules and structures
from simple precursors through making and breaking of
bonds
16. Why study Bioenergetics!
• The energy is also used to maintain concentration
gradients across membranes, heat production, for
motion, thinking, growth, etc.
• Energy manipulation for Biological Work for Life
• We have established that living systems transact energy;
–Do these transaction conform to the physical principals that
guide energy dynamics? Yes, How?
17. Bioenergetics Obey General Thermodynamics
• Living organisms conform to the general laws of
thermodynamics in their manipulation of energy
–Energy is transferred from one part of the system to another or
transformed from one form to another but it is not lost or created
–In these energy transformations entropy of the universe must
increase
–Living cells are isothermal, source of energy is usually not heat flow
from their sorroundings, they instead depend on free energy
19. Why study Bioenergetics!
• Energy manipulation occurs in living organisms
–Living organisms can neither create, from nothing nor destroy it to
nothing
–Autotrophs transform light energy into chemical energy
–Chemical energy is transformed into heat, electrical, mechanical or
chemical energy conserved by the formation of compounds
–Energy is extracted (catabolism) in a stepwise ordered fashion
• Fuel oxidation – glycolysis, fatty acid oxidation, TCA cycle
20.
21.
22.
23. Why study Bioenergetics!
• Energy manipulation occurs in living organisms cont..
–Conserved for subsequent use in anabolism,
mechanical/electrical activity and/or lost (as heat)
• Conserved through the synthesis of ATP, high energy compounds
or the reduction of electron carriers NAD, NADP, FAD
–Order and organization in living systems must be
compensated/paid for by release of energy that will increase
entropy of surroundings
24.
25.
26. Bioenergetics in Biochemistry
• Explores the energy transformations which take place in the
reactions of the ATP-ADP cycle
• The ATP-ADP cycle refers to the utilization of ATP chemical
bond energy to do work required for life, and the continuous
oxidation of fuels (carbohydrate, lipid, protein) to regenerate
this ATP
–Mechanical work, transport work, biosynthetic work, etc.
28. Thermodynamics and Energy Transformation in
Living Systems
• Biological energy transactions obey the laws of thermodynamics
• First law is the principle of conservation of energy. Energy may
change form or it may be transported from one region to another,
but it cannot be created nor destroyed
– although energy can be converted into different forms, the total amount
of energy in a system must remain constant
– There seems to be a preferred direction (predictability) of energy flow
29. Thermodynamics and Energy Transformation in
Living Systems
• Second law says that the universe always tends toward
increasing disorder. In all natural processes, the entropy of the
universe increases.
–Spontaneous processes occur in directions that increase the overall
disorder of the universe (system and surroundings)
–Sum of the entropies of a system and its surroundings must always
increase
30. Thermodynamics and Energy Transformation in
Living Systems
• Second law
–All processes whether chemical or biological progress toward a
situation of maximum randomness or disorder (entropy, S)
–Equilibrium in a system is achieved when the entropy is at a
maximum
• Energy changes in biological systems are governed by the first
and second law of thermodynamics
31. Thermodynamics and Energy Transformation in
Living Systems
• Reacting system: a collection of matter that is undergoing a
particular chemical or physical process.
– An organism, a cell, two or more reacting compounds
• Surroundings: everything else apart from the “reacting
system”
• Universe: the reacting system and surroundings
32.
33. Thermodynamics and Energy Transformation in
Living Systems
• Living cells and organisms are open systems, they exchange
materials and energy with their environment, they are never at
equilibrium with their surroundings
34. Thermodynamics and Energy Transformation in
Living Systems
–Energy is spent to create and maintain the order in the cell or
organism and surplus energy is released to the surroundings to
create disorder such that the resultant of the decrease of entropy in
the system and increase of entropy in the surroundings is a net
increase of entropy of the universe
–This is how they are able to maintain a higher degree of order than
their surroundings without violating the 2nd law of thermodynamics
35. Thermodynamic Quantities
• These describe energy changes that occur in a chemical
reaction
–Free energy/Gibb’s free energy
–Enthalpy
–Entropy
36. Gibb’s free energy
• The amount of energy available to do work during a reaction,
at constant temperature and pressure, is expressed as free-
energy or Gibb’s free energy (G)
–A state function that relates enthalpy and entropy at a particular
temperature
–Expressed in joules/mole (J/mol) or calories/mole
37. Gibb’s free energy
• The Gibbs free energy (G) of a system is a measure of the
amount of usable energy (energy that can do work) in that
system
• The change in Gibbs free energy during a reaction provides
useful information about the reaction's energetics and
spontaneity (whether it can happen without added energy)
38. Gibb’s free energy
• Each compound involved in a chemical reaction contains a
certain amount of chemical potential energy, related to the
kind and number of its bonds
39. Gibb’s free energy change
• The energy that cells use to perform metabolic work is free
energy, described by the Gibb’s free energy, G
• Energy changes associated with reactions taking place in
biological systems are therefore reported as changes in free
energy, ΔG
42. Gibb’s free energy change
• Heterotrophic cells acquire free energy from nutrient
molecules and photosynthetic cells acquire it from absorbed
solar radiation
• Both kinds of cells transform this free energy into ATP and
other energy-rich compounds capable of providing energy for
biological work at constant temperature and pressure
43. Gibb’s free energy change
• Initially reactants posses higher G than the products and the
forward reaction proceeds with net loss of G,
• The reaction proceeds until a point of equilibrium where the
energy content of products and reactants balances, ΔG is zero
–The tendency of reacting systems to move towards equilibrium
represents a driving force, its magnitude is ΔG
• Because of the associated release of energy
–Nb: There is an association between ΔG of a reacting system and
reaction equilibrium, represented by equilibrium constant (Keq)
45. Gibb’s free energy
• There is release of free energy, G, when chemical reaction
systems are moving towards equilibrium
–Change in free energy can be calculated
–It is expressed as Gibb’s free energy change or simply as ΔG
46. Gibb’s free energy change
• The equilibrium constant, Keq, defines this equilibrium
–There is a relationship between Keq and change in standard free
energy of a reaction in a particular direction
• The position of the equilibrium (the extent of converting
reactants to products) depends on
–Minimizing the difference in Gibb’s free energy between reactants
and products, ΔG
–Maximizing entropy, ΔS
47. Utility of Gibb’s free energy change
• The Gibbs free energy change of a reaction allows for prediction of:
– The direction where a chemical reaction is spontaneous,
– Their exact equilibrium position and
– The amount of work they can perform at constant temperature and pressure
• Reactions that result in a decrease in free energy, (i.e the products
have less free energy than reactants) are said to be exergonic. Such
reactions have a negative free energy change, -ΔG
• Exergonic reactions tend to occur spontaneously
48. Utility of Gibb’s free energy change
• Reactions that result in an increase in free energy, (i.e the
products have more free energy than reactants) are said to be
endergonic. Such reactions have a positive free-energy
change, +ΔG.
• Endergonic reactions are not spontaneous, require net energy
input to occur
49.
50. Entropy
• The randomness or disorder of the components of a chemical
system is expressed as entropy, S
• Entropy is expressed in joules/mole. Kelvin (J/mol.K)
• Entropy is related to the number of accessible microstates
(degree of freedom) a substance can assume
51. Entropy
• Any change in randomness of the system is expressed as
entropy change, ΔS
• ΔS is positive if randomness increases
• When the products of a reaction are less complex and more disordered than
the reactants, the reaction is said to proceed with a gain in entropy
• The thermodynamically favored reaction direction must take
into account the degree of randomness or disorder of the
chemical system
55. Order to Disorder
• ΔS is positive
–Ice melting, vapourization
• ΔS is negative
–Freeze, condensation, crystallization
56. Entropy – alternative explanations
• How dispersed the energy is within a system amongst
the ways that that system can contain energy
• Energy that is distributed or dispersed among the
various motions of molecules of the system
–Movement of heat energy from hot to cold substance
(dispersal is favored)
57. Entropy – alternative explanations
• “Entropy is the tendency for heat energy to become
evenly distributed over time
• Energy is often defined in physics as the ability to do work
• If energy is evenly distributed, it cannot move anymore and no
work gets done. So there may be some energy in the system
but with no differential (distribution) that energy is not
available to do any work” by J. Werbock – extracted from researchgate
58. How is Order Possible in Biological Systems?
• Living cell exhibit ordered processes eg. Growth and differentiation,
and build very ordered substances eg. DNA, RNA, proteins
• Does this defy 2nd law of thermodynamics?
• Cell is not an isolated system, it can take energy from the
environment – food and light
• This energy is used to generate order in the cell but, through heat and
other simpler byproducts (CO2, H2O) released into the environment,
the surroundings are disordered, therefore total entropy of
“universe” is increasing (system + surroundings)
59. How is Order Possible in Biological Systems?
• The 2nd law of thermodynamics states that the entropy of the
universe increases during all chemical and physical processes,
but it does not require that the entropy increase must take
place in the reacting system itself
• The order produced within cells as they grow and divide is
compensated for by the disorder they create in their
surroundings through the numerous reactions in the course of
their growth and division
60. Enthalpy
• Enthalpy, H: Is the heat content of the reacting system
• It reflects the number and kinds of chemical bonds in the
reactants and products
61. Enthalpy
• Heat given up from or absorbed into a reaction
–In exothermic reactions the heat content of the products is
less than that of the reactants
• ΔH has a negative value
–In endothermic reactions the heat content of the reactants
is less than that of the products, i.e the reaction system
takes up heat from its surroundings
• ΔH has a positive value
62. Enthalpy
• Is a (convenient) way of looking at the energy of a system
• Enthalpy is expressed in joules/mole (J/mol) or calories/mole
63. The Gibb’s Equation
• The Gibb’s equation describes the relationship between the
three thermodynamic variables/quantities
ΔG= ΔH – TΔS
(T= absolute temperature in Kelvin, 25°C= 298K)
• The free energy change, which is a combination of enthalpy
and entropy changes, can be used to predict the direction in
which a reaction will spontaneously proceed.
64. The Gibb’s Equation
• ΔS has a positive sign when entropy increases
• ΔH has a negative sign when heat is released from the
system to its surroundings
• Both conditions are typical of energetically favorable
processes and tend to make ΔG negative
• ΔG of a spontaneously reacting system is always negative
65. The Gibb’s Equation
• The Gibb’s free energy change depends on:
–The difference in chemical bond energy between the products
and the reactants(enthalpy change or ∆H).
• ∆H = the chemical bond energy of products – the chemical bond
energy of the reactants
–The amount of energy unavailable for work because it has gone
into an increased disorder of the system
• The increase in entropy or ∆S
–The initial concentration of substrates and products
66. Favorable reactions
• If in a particular reaction direction of a reacting system:
– The H is negative, heat is released during reaction. Reaction is exothermic
in that direction
– The S is positive, randomness increases
– Then G < 0, the reaction is "spontaneous“, “
(thermodynamically/energetically favourable) in that direction
• Such a reaction release energy and is termed exergonic
67. Unfavorable reactions
• If in a particular reaction direction of a reacting system:
– The H is positive, heat is consumed during reaction. The reaction is
endothermic in that direction
– The S is negative, randomness decreases
– Then G > 0, the reaction is “not spontaneous“ (thermodynamically
unfavourable) in that direction
– Such a reaction consumes energy and they are termed endergonic.
68. .
Exergonic and Endergonic Reactions
Exergonic Reaction
Products -less energy than reactants
Energy released
Usually Entropy increases
spontaneous
Endergonic Reaction
Products -more energy than reactants
Energy required
Usually Entropy decreases
Not spontaneous 68
69. Sign of ΔG predicts the direction of a Reaction
• The change in free energy, ΔG can be used to predict the
direction of a reaction at constant temperature and pressure.
• Consider the reaction:
A → B
70.
71.
72. 1. Negative ΔG:
• If ΔG is a negative number, there is a net loss of
energy, and the reaction goes spontaneously as
written,
• that is, A is converted into B.
• The reaction is said to be Exergonic.
73. 2. Positive ΔG:
• If ΔG is a positive number, there is a net gain of
energy,
• and the reaction does not go spontaneously from
B to A .
• Energy must be added to the system to make the
reaction go from B to A,
• and reaction is said to be Endergonic.
74. 3. ΔG is Zero:
• If ΔG = 0, the reactants and products are in
equilibrium,
• Note, when a reaction is proceeding
spontaneously, that is, free energy is being lost,
then the reaction continues until ΔG reaches zero
and equilibrium is established.
• No energy gain or lost
75. ΔG of the forward and back reactions
• The free energy of the forward reaction A → B is
equal in magnitude but opposite in sign to that of
the back reaction, B → A.
• E.g, if ΔG of the forward reaction is -5 J/mol, then
that of the back reaction is +5 J/mol.
• Note: ΔG can also be expressed in calories per
mole or cal/mol
77. Reaction Spontaneity
< ΔH > ΔH
> ΔS Spontaneous Likely spontaneous
at high temperatures
< ΔS Likely spontaneous at
low temperatures
Never spontaneous
ΔG= ΔH – TΔS
78. Reaction Spontaneity
ΔG= ΔH – TΔS
• ∆H < 0 & ∆S > 0: enthalpically favored (exothermic) and entropically
favored. Spontaneous reaction (exergonic) at all temperatures
• ∆H < 0 & ∆S < 0: enthalpically favored but entropically opposed.
Spontaneous reaction only at temperatures below T=∆H/∆S
• ∆H > 0 & ∆S > 0: enthalpically opposed (endothermic) but entropically
favored. Spontaneous reaction only at temperatures above T=∆H/∆S
• ∆H > 0 & ∆S < 0: enthalpically and entropically opposed.
Unspontaneous reaction (endergonic) at all temperatures
79. Reaction Spontaneity
• ∆G is not an indicator of the velocity of the reaction or the
rate at which equilibrium is reached
• The velocity of the reaction depends on the amount of
enzyme available and the energy of the activation of the
reaction
80. Standard vs Non-standard Free Energy Change
• The change in free energy can be designated as standard or
actual, symbolized as ΔGo and ΔG, respectively
• Standard free energy change, ΔGo (with the superscript “o”),
is the free energy change at standard temperature (298K) and
pressure (1 atm) when reactants and products are at a
concentrations of 1 mol/L
–ΔGo is a constant for a given reaction
81. Standard vs Non-standard Free Energy Change
• Biochemical Standard free energy change, ΔGoʹ (transformed
standard free energy change) Is defined as a standard change
in free energy (i.e at 298K, 1atm and 1 mol/L reactants and
products) at pH 7
82. Standard vs Non-standard Free Energy Change
• Actual change in free energy, ΔG (without the superscript
“o”), is the more general/actual free energy change because
• It expresses the change in free energy and, thus, the direction
of a reaction at any specified concentration of products and
reactants
• In the cell, reactants and products are almost never at 1 mol/L
(1M) concentrations
83. Standard vs Actual Free Energy Change
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84. Standard vs Actual Free Energy Change
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85. Actual Free Energy Change, ΔG
ΔG depends on the concentration of Reactants and
Products
• The ΔG of the reaction A → B depends on the concentration of the
reactant and product.
• At constant Temperature and Pressure, the following relationship
can be derived:
ΔG = ΔGo + RT ln [B]/ [A]
86. ΔG = ΔGo + 2.303 RT Log [B]
[A]
• Where
–ΔG = Change in Free Energy
–ΔGo = The Standard Free Energy Change
–R = The Gas Constant (8.3 J/mol.K)
–T = The Absolute Temperature (K)
–[A] = The Actual Reactant Concentration
–[B] = The Actual Product Concentration
87. Tractor capability coupled with soil condition (dry vs wet)
https://agriculturalmachinery.w
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88. Tractor capability coupled with soil condition (dry vs wet)
https://www.quora.com/What-
are-the-advantages-of-ploughing-
the-soil-before-sowing-seeds
89. • A reaction with a positive ΔGo can proceed in the
forward direction (have a negative overall ΔG) if the
ratio of products to reactants ([B]/[A]) is sufficiently
small
–That is there is a large amount of reactants and very little
products
90. • ∆G depends on [reactant] and [products]. Therefore, it
can be negative even if ∆G°’ is positive, if the
[reactants] is much much larger than [products]
–Or if products are immediately removed from the system
• So a positive ∆G°’ doesn’t always mean that the
reaction won’t go forward in vivo
–It depends on how the levels of reactants and products
are controlled
91. • ∆G of ATP hydrolysis in vivo (in the cellular
environment) is larger negative number than the ∆G°’
of ATP hydrolysis in vitro (in experimental setup)
• At a normal physiological condition in cells, the
[ADP].[Pi]/[ATP] ratio is maintained at a low fraction value
92. Standard free energy change, ΔGo
• The standard free energy change, ΔGo, is so called because it
is equal to the free energy change, ΔG, under standard
conditions,
• that is, when Reactants and Products are kept at 1 mol/L
concentrations
• Under these conditions, the natural logarithm of the ratio of
products to reactants is zero
–Ln 1=0 or Log 1 =0
94. Relationship Between ΔGo and Keq
• The ∆G° (or ∆G°’ ) is related to the equilibrium constant,
Keq, for a reaction
95. Relationship Between ΔGo and Keq
• In a reaction A → B, a point of equilibrium is reached at which
no further net chemical change takes place,
• that is, when A is being converted to B as fast as B is being
converted to A.
• In this state, the ratio of [B] to [A] is constant, regardless of the
actual concentrations of the two compounds:
96. • Keq = [B]eq
[A] eq
Where
• Keq is the equilibrium constant
• [A]eq and [B]eq are the concentrations of A and B at
equilibrium
97. • If the reaction A → B is allowed to go to equilibrium at
constant Temperature and Pressure,
• then at equilibrium the overall free energy change ΔG is zero
• Therefore,
ΔG = ΔGo + 2.303 RT Log[B]eq/[A]eq = 0
98. • Where the actual concentrations of A and B are equal to the
equilibrium concentrations of reactant and product, [A]eq and
[B]eq, and their ratio as shown above is equal to the Keq.
• Thus,
ΔGo = - 2.303 RT Log Keq
ΔGo = -RT lnKeq
99. Relationship Between ΔGo and Keq
• ΔGo can be obtained from the equilibrium constant of
a reaction system
•
100. This reaction allows some simple predictions:
• If Keq = 1, Then ΔGo = 0 A ↔ B
• If Keq > 1, Then ΔGo < 0 A → B
• If Keq < 1, Then ΔGo > 0 A ← B
101. ΔGo is predictive only under standard conditions:
• Under standard conditions, ΔGo can be used to predict the
direction a reaction proceeds because, under these
conditions, ΔGo is equal to ΔG.
• However, ΔGo cannot predict the direction of a reaction
under physiologic conditions
• If the standard free energy change (∆Go) can be determined,
then the actual free energy change of a reaction (∆G) can be
calculated.
102. • Although ΔGo represents energy changes at these non-
physiologic concentrations of reactants and products,
• It is nonetheless useful in comparing the energy changes of
different reactions.
–Free energy change of different reactions have been determined
experimentally at standard conditions
• Furthermore, ΔGo can readily be determined from
measurement of the equilibrium constant
103. • In cells metabolites do not exist in molar concentrations
• We talk about ΔG, rather than ∆G°’
104. Reaction Coupling
• Free energy changes in a (metabolic) pathway are
additive and those with positive values can be driven by
others with negative ∆G values.
• The biochemical standard free energy changes ∆G°’ are
additive in any sequence of consecutive reactions, as are
the free energy changes, ΔG
107. • This additive property of free energy changes is very
important in biochemical pathways through which substrates
must pass in a particular direction ( for example A →B → C →
D → E…)
• As long as the sum of the ΔGs of the individual reactions in a
pathway is negative, the pathway can potentially proceed as
written
–even if some of the individual reactions of the pathway have a
positive ΔG
• The actual rate of the reactions does, of course, depend on
the activity of the enzymes that catalyze the reactions.
108. Biochemical Reactions and their ΔGs
• Hydrolysis reactions – favourable, smaller –ve ΔG
• Isomerizations – occur are near equilibrium
• Oxidation of reduced fuels – favourable, large –ve ΔG
109.
110. ATP and Other High Energy metabolites
• Some nutrient molecules have fuel qualities
–High in chemical potential energy
• Catabolism of such nutrient molecules by heterotrophs
releases this chemical free energy
• Some of this nutrient derived free energy is used (conserved
in) to synthesize ATP from ADP and Pi, directly or indirectly
111. ATP and Other High Energy metabolites
• Catabolism of such nutrient molecules by heterotrophs
releases this chemical free energy
112. ATP and Other High Energy metabolites
• ATP donates some of this conserved (or stored) energy in
anabolic processes to make them thermodynamically feasible,
yielding ADP + Pi or AMP + PPi
–It does this as it participates covalently in those processes (most
cases)
–In other cases through straight forward hydrolysis of ATP without
covalent association with the reactants (mechanical motion/trans
membrane transportation processes)
113.
114.
115. ATP and Other High Energy metabolites
• ATP functions as an intermediate energetic compound that
metabolic processes can use
–Other polyphosphorylated nucleotides are also energy rich
compounds and are used similar to or interchangeably with ATP
–GTP, UTP, etc.
• There are other ‘energy rich’ metabolites that provide free
energy for metabolic reactions
–Can be synthesized directly from catabolism(oxidation) of fuels
–Can be synthesized from hydrolysis of ATP
116. ATP and Other High Energy metabolites
• Some of these high-energy compounds can transfer a phosphate
group to make ATP
• The other high energy intermediates/metabolites referred to are:
– Phosphorylated compounds, some with mixed anhydride bond
– Thioesters where sulfur atom replace the Oxygen in the ester bond
• ATP and these other energy rich intermediates/metabolites are called
so because of the large negative free energy change values of their
hydrolysis
– They include PEP, Creatine phosphate, 1,3-Bisphosphoglycerate, Acyl-CoA
117. ATP and Other High Energy metabolites
• Some of these high-energy compounds can transfer a phosphate
group to make ATP
118.
119. ATP and Other High Energy metabolites
• The designation as high-energy compounds implies that the
products of their hydrolytic cleavage are more stable forms
than the original compound
– it is the thermodynamic stability/favourableness of the hydrolytic
products of the high energy compounds that is the source of the
free energy released when their hydrolyzed,
120. ATP as the Energy Currency
• ATP is short for adenosine triphosphate
• ATP has a central role in the transfer of energy in biological systems.
(the energy currency)
• It links catabolism and anabolism
• Through catabolism of nutrient molecules, heterotrophs obtain energy
and use it to make ATP
121. ATP as the Energy Currency
• ATP in turn is used as a source of energy for anabolic
reactions.
–i.e Endergonic processes such as:
• The synthesis of metabolic intermediates and macromolecules
from smaller precursors
• Mechanical motion
• Transmembrane transportation of molecules, etc.
122. Why is ATP an Energy-Rich Molecule
I. The hydrolytic cleavage of the terminal phosphoanhydride
bond of ATP relieves some of the intramolecular
electrostatic repulsion existing in ATP
–Repulsion between the negatively charged Oxygen atoms of
phosphates and between the positively charged Phosphorus atoms
II. Formation of several resonance forms, by delocalization of
the pi electrons, stabilizes free inorganic phosphate (Pi)
–The Pi can not enjoy the freedom of resonance when it is bonded to
ADP
123. Why is ATP an Energy-Rich Molecule
III. The entropy increases. There is a greater stability in the
products because there exists a greater entropy; i.e. more
randomness. 1 mole of reactants has a higher energy than 2
moles of products. Disorder is favored over order according
to the 2nd law of thermodynamics
• The three factors make ATP hydrolysis relatively highly
exergonic
124. Resonance Stabilization
• Resonance allows for electron delocalization, in which the
overall energy of a molecule is lowered since its electrons
occupy a greater volume
• Molecules that experience resonance are more stable than
those that do not. These molecules are said to be resonance
stabilized
125.
126.
127. ATP as the Energy Currency
• The biochemical free energy change, ∆G°’, of ATP
hydrolysis is very different from the actual free energy
change, ∆G, in cellular conditions
–The [ATP], [ADP], [Pi] are far from the standard values used
to obtain ∆G°’
–Regulatory mechanism of ATP synthesis and breakdown hold
[ATP] far above the equilibrium concentration with its
hydrolytic products, ADP and Pi
128. ATP as the Energy Currency
–This makes ∆G a larger negative number than ∆G°’
–When cellular [ATP] decreases not only is the cell losing
energy molecules (losing its energy charge) but the potency
of the available (remaining) ATPs diminishes as well – i.e
their hydrolysis yields less free energy
129. ATP as the Energy Currency
• With the exception of usage of ATP in processes involving:
–Mechanical motion by the change of protein conformation (muscle
contraction, receptor activation)
–Active transmembrane transport
• Most other reactions in which ATP is the source of free energy
–ATP provides the energy by participating in the reaction covalently
–Groups Pi, PPi or AMP, are transiently transferred (covalently bound)
to the reactant (or enzyme) and then later displaced as the products
are released
130.
131.
132. ATP as the Energy Currency
• ATP donates phosphoryl, pyrophosphoryl or adenylyl groups in its
covalent involvement in metabolic reactions that use ATP to become
feasible
• Which group is donated (gets covalently attached to the reactant) and
which is displaced depends on which of the α, β and δ phosphates of
ATP has been attacked
– Hydrolysis of the α-β phosphoanhydride bond releases more free energy than
hydrolysis of the β-γ phosphoanhydride bond
• Reactions where AMP is donated are called adenylylation
– Inorganic pyrophosphatase hydrolyzes the PPi to 2Pi
134. ATP as the Energy Currency
• Adenylylation is more thermodynamically favourable than transfer of
phosphory group
• Adenylylation is usually the mechanism of energy coupling in the very
unfavourable metabolic reactions that use ATP as the source of free
energy
– Higher ∆G°’ of the α-β phosphoanhydride bond hydrolysis
– Extra free energy from PPi hydrolysis
137. Other High Energy Metabolites
• 1,3-Bisphosphoglycerate
– A glycolytic intermediate
– Hydrolysis of its mixed anhydride has a large negative ∆G°’ which is used to
transfer a phosphate to ADP producing ATP
– The product 3-phosphoglycerate enjoys resonance stabilization as it
interconverts between the two possible resonance forms
– For the above reasons 1,3-BPG high energy metabolite and it hydrolysis is
exergonic
138.
139. Other High Energy Metabolites
• Phosphoenolpyruvate
– Another glycolytic intermediate, has a phosphate ester bond
– Hydrolysis of phosphoester bond has a large negative ∆G°’ which is used to
transfer a phosphate to ADP producing ATP
– Pyruvate produced by the hydrolysis of PEP has possibility for tautomerization
to a more stable keto form of the compound
• This keto – enol tautomerization is not possible in PEP, the possibility to form a more
stable intermediate makes this dephosphorylation favourable and therefore exergonic
– That free energy released does the work of phosphorylating ADP into ATP
140.
141. Other High Energy Metabolites
• Phosphocreatine
– Is a form of energy storage in muscle, a quick supply of ATP during muscular
activity (recycling ATP from ADP)
– Hydrolysis of P-N bond has a large negative ∆G°’ which is used to transfer a
phosphate to ADP producing ATP
– creatine produced enjoys resonance stabilization, this favors its
dephosphorylation
– That free energy released does the work of phosphorylating ADP into ATP
• When there is ample ATPs some can hydrolyze and power creatine phosphorylation and
therefore storing/conserving that energy in the high energy molecule phsophocreatine
142.
143. Other High Energy Metabolites
• Thioesters
– AcylCoA such as acetylCoA are common and important thioesters in
metabolism
– Thioesterification of an acyl group to CoA activates/energizes the acyl ready
for further reactions such as transacylation/condensation/oxidation-reduction
reactions
– Acetate (or other carboxylate) has possibility for resonance stabilization which
it looses when in a thioester bond with CoA (hence becoming less stable)
– This chemical fact (state of affairs) makes the thioesters like acetylCoA high
energy compounds
– The energy that holds this compound together is released as free energy
upon the thioester bond hydrolysis and it can be used to power reactions
144.
145.
146. Other High Energy Metabolites
• These hydrolysis reactions with large -ve ∆G°’, produce products more
stable than reactants for the following reasons:
– Relieving bond strain and electrostatic repulsions by charge separation
– Products can ionize and achieve better stability through resonance
delocalization
– Product stabilization through isomerization
– Products are ions which can undergo resonance stabilization
150. ATP as the energy currency
• The energy from ATP is obtained from the energy that is released
when ATP is hydrolyzed to ADP + Pi or AMP +2Pi.
• The hydrolysis of ATP and other high energy phosphate compounds
is accompanied by a large negative free energy change
• This energy is coupled to drive other unfavorable reactions
151. Energy coupling
• The central issue in bioenergetics is the means by which energy from
fuel metabolism (or light capture) is coupled to a cell’s energy
requiring reactions.
• Because cell function depends on macromolecules such as DNA,
proteins whose free energy of formation is positive, cells couple
these energy-requiring (endergonic) reactions to other reactions that
release energy (exergonic) so that the overall process is exergonic
• The usual source of free energy in coupled biological reactions is the
energy released by the breakage of phosphoanhydride bonds such
as those of ATP.
152. Simple examples as analogy of reaction coupling
• An object at the top of an inclined plane has a certain amount of potential
energy.
• Through appropriate string and pulley device this object can be coupled to
another smaller object such that when this elevated object slides down the
spontaneous downward motion will lift the smaller object. This amount of
energy available to do work is the free-energy change, G
153. • The energetically
unfavourable reaction Y → X
is driven by the energetically
favourable reaction, C → D,
because the free energy
change for the coupled
reactions is overall negative
Coupled Reaction
154. Coupled Reaction
• The third reaction is the sum of the reactions 1 and 2, and the G₃
is the arithmetic sum of G₁ and G₂. Because G₃ is negative, the
overall reaction is exergonic and proceeds spontaneously.
155. Example of a Coupled Reaction
• Example: synthesis of glucose-6-phosphate from glucose
1. Glucose + Pi → G-6-P + H2O ∆G°´= 13.8 kJ/mol
2. ATP + H2O → ADP + Pi ∆G°´= -30.5 kJ/mol
• The first reaction will not proceed alone as it has a
positive ∆G°´
• H2O and Pi are the common intermediates in these
reactions
• Overall reaction is:
ATP + glucose → ADP + G-6-P
• Overall ∆G°´= 13.8 - 30.5 = -16.7 kJ/mol
• So overall reaction is exergonic
• Energy stored in the bonds of ATP is used to drive the
synthesis of G-6-P
156. Biological Oxidation-Reduction Reactions
• The transfer of electrons in redox reactions is a common feature in
metabolism
• One chemical species looses electrons, it is oxidized, another one
gains electrons, it is reduced
• This flow of electrons is directly or indirectly responsible for all work
done by living organisms
• The ultimate source of electrons in heterotrophs are reduced
compounds, usually food substances (fuel)
157. Biological Oxidation-Reduction Reactions
• Electrons harvested as the fuels are oxidized and converted into
series of metabolic intermediates are carried by specialized carriers
to electron acceptors
• This train of transfer of electrons to an acceptor with higher
reduction potential releases energy that is channeled (transduced) to
useful cellular work - they flow down the potential energy slope
• Various enzymes and other proteins can use this energy to do
biological work
– Proton pumping by mitochondrial membrane enzyme complexes
– which provides the energy that later powers ATP synthesis
159. Types of Biological Redox Reactions
• Transfer as electrons
• Transfer as hydrogen atom(s), e- and H+ or hydride ion :H-
– FAD accepts electrons as the hydrogen atom (H) which is equivalent to two H+
and two electrons
– NAD+ accept electrons as the hydride ion (H:-) which is equivalent to one H+
and 2 electrons
160. Types of Biological Redox Reactions
• Direct combination with O2
– The hydrocarbon is the electron donor and the O2 the electron acceptor
161. Oxidation-Reduction Potential
• Reduction potential, E, is the measure of the affinity of a
chemical species for electrons
–Reduction potentials determined at standard conditions E°
• Electrons flow from the species (half cell) with lower E° to that
with higher/more positive E°
–Strength of this tendency to flow is proportional to ΔE°
162. Oxidation-Reduction Potential
• Reduction potential is affected not just by the nature of the
chemical species but also buy their activity, which is a function
of their concentration
–There is standard reduction potential-E°, and actual reduction
potential-E
• The energy associated with this flow of electrons is a form of
free energy
–Its magnitude, ΔG° is proportional to ΔE°