This document discusses metabolism of carbohydrates, specifically glycolysis. It begins by defining metabolism and categorizing metabolic pathways as anabolic, catabolic, or amphibolic. It then describes the two phases of glycolysis - an energy investment phase and an energy generation phase. Key steps in glycolysis including phosphorylation, isomerization, and oxidation reactions are outlined. Regulation of glycolysis and glucose transport mechanisms into cells are also summarized. Aerobic and anaerobic glycolysis are compared, and the roles of NADH, pyruvate, and lactate in energy production are described.
Carbohydrate digestion begins in the mouth where salivary amylase breaks down starches. Pancreatic amylase continues digestion in the small intestine. Several disaccharidases in the intestinal mucosal cells, such as maltase and sucrase, further break down carbohydrates into monosaccharides like glucose and fructose. These monosaccharides are then absorbed into the bloodstream through active transport mechanisms involving sodium-glucose cotransporters and glucose transporters. Deficiencies in disaccharidases can cause osmotic diarrhea due to undigested carbohydrates passing into the large intestine.
The uronic acid pathway, also known as the glucoronic acid pathway, is an alternative oxidative pathway for glucose that results in the synthesis of glucoronic acid, UDP-glucose, pentoses, and ascorbic acid in lower animals. The pathway includes reactions like those catalyzed by phosphoglucomutase and UDP-glucose dehydrogenase. Administration of drugs such as barbitol and chlorobutanol increases the uronic acid pathway and synthesis of glucoronate from glucose, which is required for detoxification of these drugs. Essential pentosuria is a rare genetic disorder caused by a deficiency of xylitol dehydrogenase, preventing the conversion of L-xylulose to xylitol and
This document summarizes the glucuronic acid pathway, an alternative oxidative pathway for glucose metabolism. It provides UDP-glucuronic acid, which is used to conjugate bilirubin, steroids, and drugs to make them more water soluble and excretable. The pathway also synthesizes glycosaminoglycans and is involved in vitamin C synthesis in many animals. Key steps include the conversion of glucose-6-phosphate to UDP-glucuronate and the subsequent production of L-gulonate, a precursor for ascorbic acid synthesis. Certain genetic disorders can cause excess excretion of metabolites from this pathway such as L-xylulose in essential pentosuria.
Glycolysis is the pathway that converts glucose to pyruvate, producing a small amount of ATP. It occurs in the cytosol and is divided into three phases: energy investment, splitting, and energy generation. Glycolysis is regulated by three key enzymes - hexokinase, phosphofructokinase, and pyruvate kinase. In anaerobic conditions, pyruvate is converted to lactate to regenerate NAD+ for continued glycolysis. Glycolysis is an important energy pathway in tissues lacking mitochondria.
carbohydrate metabolism, Glycolysis, metabolic process of carbohydrates, EMP ...RajkumarKumawat11
carbohydrate metabolism, Glycolysis, metabolic process of carbohydrates, EMP pathway, Embden- Meyerof-Paranas pathway, cabohydrate metabolic process for study, A presentation on cabohydrate metabolic process i.e. Glycolysis
This PPT contains content of Gluconeogenesis, Steps involved in Gluconeogenesis, (Gluconeogenesis from Pyruvate, Gluconeogenesis from lactate, Gluconeogenesis from amino acids, Gluconeogenesis from glycerol, Gluconeogenesis from Propionate), Regulation and significance of Gluconeogenesis
Complete Set of Metabolism of Carbohydrate in that second chapter, glycolysis.
This presentation covers complete glycolysis pathway with step wise animated reactions and it includes clinical aspects also. This presentation is good for MBBS students.
Carbohydrate digestion begins in the mouth where salivary amylase breaks down starches. Pancreatic amylase continues digestion in the small intestine. Several disaccharidases in the intestinal mucosal cells, such as maltase and sucrase, further break down carbohydrates into monosaccharides like glucose and fructose. These monosaccharides are then absorbed into the bloodstream through active transport mechanisms involving sodium-glucose cotransporters and glucose transporters. Deficiencies in disaccharidases can cause osmotic diarrhea due to undigested carbohydrates passing into the large intestine.
The uronic acid pathway, also known as the glucoronic acid pathway, is an alternative oxidative pathway for glucose that results in the synthesis of glucoronic acid, UDP-glucose, pentoses, and ascorbic acid in lower animals. The pathway includes reactions like those catalyzed by phosphoglucomutase and UDP-glucose dehydrogenase. Administration of drugs such as barbitol and chlorobutanol increases the uronic acid pathway and synthesis of glucoronate from glucose, which is required for detoxification of these drugs. Essential pentosuria is a rare genetic disorder caused by a deficiency of xylitol dehydrogenase, preventing the conversion of L-xylulose to xylitol and
This document summarizes the glucuronic acid pathway, an alternative oxidative pathway for glucose metabolism. It provides UDP-glucuronic acid, which is used to conjugate bilirubin, steroids, and drugs to make them more water soluble and excretable. The pathway also synthesizes glycosaminoglycans and is involved in vitamin C synthesis in many animals. Key steps include the conversion of glucose-6-phosphate to UDP-glucuronate and the subsequent production of L-gulonate, a precursor for ascorbic acid synthesis. Certain genetic disorders can cause excess excretion of metabolites from this pathway such as L-xylulose in essential pentosuria.
Glycolysis is the pathway that converts glucose to pyruvate, producing a small amount of ATP. It occurs in the cytosol and is divided into three phases: energy investment, splitting, and energy generation. Glycolysis is regulated by three key enzymes - hexokinase, phosphofructokinase, and pyruvate kinase. In anaerobic conditions, pyruvate is converted to lactate to regenerate NAD+ for continued glycolysis. Glycolysis is an important energy pathway in tissues lacking mitochondria.
carbohydrate metabolism, Glycolysis, metabolic process of carbohydrates, EMP ...RajkumarKumawat11
carbohydrate metabolism, Glycolysis, metabolic process of carbohydrates, EMP pathway, Embden- Meyerof-Paranas pathway, cabohydrate metabolic process for study, A presentation on cabohydrate metabolic process i.e. Glycolysis
This PPT contains content of Gluconeogenesis, Steps involved in Gluconeogenesis, (Gluconeogenesis from Pyruvate, Gluconeogenesis from lactate, Gluconeogenesis from amino acids, Gluconeogenesis from glycerol, Gluconeogenesis from Propionate), Regulation and significance of Gluconeogenesis
Complete Set of Metabolism of Carbohydrate in that second chapter, glycolysis.
This presentation covers complete glycolysis pathway with step wise animated reactions and it includes clinical aspects also. This presentation is good for MBBS students.
Glycolysis is the metabolic pathway that converts glucose into pyruvate, generating a small amount of ATP. It occurs in the cytosol of cells and is the first step in both aerobic and anaerobic respiration. The key steps are the phosphorylation of glucose to trap it in cells, and the splitting of a six-carbon molecule into two three-carbon molecules. Under anaerobic conditions, glycolysis produces 2 ATP and pyruvate is reduced to lactate. Aerobically, glycolysis produces 8 ATP as NADH enters the electron transport chain. Glycolysis is regulated by hexokinase, phosphofructokinase, and pyruvate kinase.
Glycogen is the major storage form of glucose found mainly in the liver and skeletal muscles. It is formed from glucose through glycogenesis and broken down into glucose through glycogenolysis. These pathways are regulated by enzymes like glycogen synthase and glycogen phosphorylase in response to hormones like insulin and glucagon to maintain blood glucose levels. Deficiencies in enzymes of glycogen metabolism can result in glycogen storage diseases characterized by hypoglycemia, hepatomegaly and other symptoms.
Heme is an essential prosthetic group that contains iron. It is synthesized through a series of enzymatic reactions starting from glycine and succinyl-CoA. The rate-limiting first step is catalyzed by ALA synthase. Deficiencies in enzymes involved in heme synthesis can cause porphyrias, which are characterized by accumulation of porphyrins or their precursors. Porphyrias can have cutaneous or neurological manifestations depending on the site of accumulation. Bilirubin is a breakdown product of heme catabolism and is conjugated and excreted in bile and feces. Hyperbilirubinemia can occur due to overproduction, defects in conjugation or excretion
This document discusses gluconeogenesis, which is the formation of glucose from non-carbohydrate precursors in the liver and kidneys. Gluconeogenesis is important for maintaining blood glucose levels during periods of fasting or low carbohydrate intake. It involves 10 enzymatic steps, with 7 reversing the reactions of glycolysis. The key substrates used for gluconeogenesis include lactate, glycerol, certain amino acids, and intermediates of the citric acid cycle. Gluconeogenesis is regulated by hormones like insulin and glucagon, as well as feedback inhibition based on energy levels and metabolite concentrations.
This document discusses glycogen metabolism pathways. It describes that glycogen metabolism has two pathways: glycogenesis and glycogenolysis. Glycogenesis is the formation of glycogen in the liver and muscles, requiring ATP and UTP. Glycogenolysis is the degradation of stored glycogen in the liver and muscles by glycogen degrading enzymes. Glycogen storage diseases can occur due to deficiencies in the enzymes involved in glycogenesis or glycogenolysis.
1) Glycolysis breaks down glucose to pyruvate, generating a small amount of ATP. Key enzymes include hexokinase, phosphofructokinase, and pyruvate kinase.
2) Pyruvate is oxidized to acetyl-CoA in mitochondria by the pyruvate dehydrogenase complex, producing NADH.
3) Acetyl-CoA then enters the citric acid cycle, where it is oxidized to carbon dioxide, generating more NADH and FADH2. This fuels the electron transport chain to produce large amounts of ATP through oxidative phosphorylation.
Glycogenolysis is the breakdown of glycogen into glucose. It occurs primarily in the liver and muscles, where the key enzyme glycogen phosphorylase catalyzes the shortening and removal of chains and branches from glycogen to produce glucose-1-phosphate and then glucose-6-phosphate. Glycogenolysis is regulated through the activation of phosphorylase and its inhibitor, as well as the role of calcium in stimulating glycogen breakdown in muscles.
Reference Harper Illustrated book of Biochemistry
Applying laws of Thermodynamics to Biochemistry.
Diferent types of Reactions, exergonic and edergonic,
Illustrated explain of Role of ATP in our body,
Brief concept on ATP production and high energy phosphate,
ATP/ADP cycle and about Creatine Kinase
The electron transport chain is comprised of a series of enzymatic reactions within the inner membrane of the mitochondria, which are cell organelles that release and store energy for all physiological needs.
As electrons are passed through the chain by a series of oxidation-reduction reactions, energy is released, creating a gradient of hydrogen ions, or protons, across the membrane. The proton gradient provides energy to make ATP, which is used in oxidative phosphorylation.
The document summarizes the process of glycolysis. It discusses how glycolysis involves 10 steps divided into 3 stages. The first stage converts glucose to fructose 1,6-bisphosphate. The second stage cleaves this molecule into two 3-carbon fragments. The third stage oxidizes these fragments to pyruvate, producing ATP through substrate-level phosphorylation. Key intermediates like glucose-6-phosphate and 1,3-bisphosphoglycerate have properties that allow harvesting of energy to produce ATP. The document also notes how glycolysis traps glucose within cells and provides building blocks for biosynthesis.
This document summarizes several pathways involved in carbohydrate metabolism. It describes the hexose monophosphate pathway (HMP pathway), which provides an alternative route for glucose metabolism and is significant for biosynthesis of NADPH and pentose sugars. It does not consume or produce ATP. The document also summarizes the gamma amino butyrate (GABA) shunt, which converts glutamate to succinate via GABA. Finally, it provides an overview of glycogen metabolism, describing glycogen synthesis from glucose and glycogen breakdown into glucose.
Gluconeogenesis- Steps, Regulation and clinical significanceNamrata Chhabra
Gluconeogenesis- Thermodynamic barriers, substrates of gluconeogenesis, reciprocal regulation of glycolysis and gluconeogenesis, biological and clinical significance
The HMP shunt, also known as the pentose phosphate pathway or phosphogluconate pathway, is an alternative pathway to glycolysis and the TCA cycle for glucose oxidation. It is more anabolic in nature and concerned with biosynthesis of NADPH and pentoses. The pathway occurs in the cytosol of tissues involved in biosynthesis like the liver, adipose tissue, and erythrocytes. It is significant in generating NADPH and pentoses like ribose-5-phosphate. NADPH is important for biosynthesis of fatty acids, steroids, and antioxidant defense while pentoses are precursors for nucleic acid synthesis. Regulation involves inhibition of the first step by NADPH. Genetic deficiencies can
The document summarizes the urea cycle, which takes place in the liver and involves several enzymes that convert toxic ammonia produced from protein metabolism into urea that can be excreted by the kidneys. The cycle includes the enzymes carbamoyl phosphate synthetase, ornithine transcarbamoylase, argininosuccinate synthetase, argininosuccinate lyase, and arginase. Defects in the enzymes can lead to metabolic disorders where specific products accumulate, such as ammonia, ornithine, citrulline, or arginine. The cycle is regulated by factors like carbamoyl phosphate synthetase and levels of protein intake.
This document provides information about enzymes including their history, characteristics, classification, and mechanisms of action. Some key points:
- Enzymes are organic biocatalysts that accelerate chemical reactions by lowering the activation energy. They are not consumed by the reactions they catalyze.
- The term "enzyme" was first used in the 19th century to describe digestion processes. Important early discoveries included identifying enzymes responsible for starch digestion and fermentation.
- Enzymes are usually proteins but can also be RNA. They are highly specific and act as catalysts by lowering the activation energy of reactions through transition state stabilization.
- The International Union of Biochemistry and Molecular Biology (IUBMB)
It is an metabolic pathway of synthesis of glucose from non carbohydrate precursors like pyruvate, lactate, amino acid, glycerol etc. Main sites are liver and kidney. It uses enzymes from both cytosol and mitochondria.
Cholesterol biosynthesis is a multi-step process that begins with acetyl-CoA and occurs primarily in the liver and other tissues. Key steps include the conversion of HMG-CoA to mevalonate by the rate-limiting enzyme HMG-CoA reductase. Cholesterol can then be used for membrane structure, steroid hormone synthesis, or converted to bile acids which are secreted in the bile. Cholesterol levels are regulated by feedback inhibition of HMG-CoA reductase and uptake/secretion of cholesterol and bile acids. Statins lower cholesterol by inhibiting HMG-CoA reductase.
Glycogen is the storage form of carbohydrates in animals, analogous to starch in plants. Glycogen is synthesized from glucose through glycogenesis, which occurs predominantly in the liver and muscles, and stored glycogen is broken down to glucose through glycogenolysis. Glycogenesis is regulated by hormones like insulin, epinephrine, and glucagon that control intracellular cAMP levels and the phosphorylation state of glycogen synthase to convert it between its active and inactive forms.
This document discusses glycolysis, the pathway that breaks down glucose to pyruvate. Glycolysis occurs in the cytosol of cells and can proceed with or without oxygen. It is an important pathway for ATP generation. The document outlines the 10 steps of glycolysis, including an energy investment phase where ATP is used to phosphorylate glucose, and an energy generation phase where ATP is regenerated. Phosphofructokinase is identified as the rate-limiting step. The fate of pyruvate, the end product, depends on oxygen availability, leading to aerobic or anaerobic metabolism.
This document discusses carbohydrate metabolism and glycolysis. It begins by classifying carbohydrate metabolism into glycolysis, the Krebs cycle, the hexose monophosphate shunt, glycogenesis, glycogenolysis, and gluconeogenesis. It then provides details on glycolysis, including that it converts glucose to pyruvate or lactate, involving 10 reactions in 3 stages. Key enzymes and reactions in each stage are described. The document also discusses regulation of glycolysis and differences between hexokinase and glucokinase.
Glycolysis is the metabolic pathway that converts glucose into pyruvate, generating a small amount of ATP. It occurs in the cytosol of cells and is the first step in both aerobic and anaerobic respiration. The key steps are the phosphorylation of glucose to trap it in cells, and the splitting of a six-carbon molecule into two three-carbon molecules. Under anaerobic conditions, glycolysis produces 2 ATP and pyruvate is reduced to lactate. Aerobically, glycolysis produces 8 ATP as NADH enters the electron transport chain. Glycolysis is regulated by hexokinase, phosphofructokinase, and pyruvate kinase.
Glycogen is the major storage form of glucose found mainly in the liver and skeletal muscles. It is formed from glucose through glycogenesis and broken down into glucose through glycogenolysis. These pathways are regulated by enzymes like glycogen synthase and glycogen phosphorylase in response to hormones like insulin and glucagon to maintain blood glucose levels. Deficiencies in enzymes of glycogen metabolism can result in glycogen storage diseases characterized by hypoglycemia, hepatomegaly and other symptoms.
Heme is an essential prosthetic group that contains iron. It is synthesized through a series of enzymatic reactions starting from glycine and succinyl-CoA. The rate-limiting first step is catalyzed by ALA synthase. Deficiencies in enzymes involved in heme synthesis can cause porphyrias, which are characterized by accumulation of porphyrins or their precursors. Porphyrias can have cutaneous or neurological manifestations depending on the site of accumulation. Bilirubin is a breakdown product of heme catabolism and is conjugated and excreted in bile and feces. Hyperbilirubinemia can occur due to overproduction, defects in conjugation or excretion
This document discusses gluconeogenesis, which is the formation of glucose from non-carbohydrate precursors in the liver and kidneys. Gluconeogenesis is important for maintaining blood glucose levels during periods of fasting or low carbohydrate intake. It involves 10 enzymatic steps, with 7 reversing the reactions of glycolysis. The key substrates used for gluconeogenesis include lactate, glycerol, certain amino acids, and intermediates of the citric acid cycle. Gluconeogenesis is regulated by hormones like insulin and glucagon, as well as feedback inhibition based on energy levels and metabolite concentrations.
This document discusses glycogen metabolism pathways. It describes that glycogen metabolism has two pathways: glycogenesis and glycogenolysis. Glycogenesis is the formation of glycogen in the liver and muscles, requiring ATP and UTP. Glycogenolysis is the degradation of stored glycogen in the liver and muscles by glycogen degrading enzymes. Glycogen storage diseases can occur due to deficiencies in the enzymes involved in glycogenesis or glycogenolysis.
1) Glycolysis breaks down glucose to pyruvate, generating a small amount of ATP. Key enzymes include hexokinase, phosphofructokinase, and pyruvate kinase.
2) Pyruvate is oxidized to acetyl-CoA in mitochondria by the pyruvate dehydrogenase complex, producing NADH.
3) Acetyl-CoA then enters the citric acid cycle, where it is oxidized to carbon dioxide, generating more NADH and FADH2. This fuels the electron transport chain to produce large amounts of ATP through oxidative phosphorylation.
Glycogenolysis is the breakdown of glycogen into glucose. It occurs primarily in the liver and muscles, where the key enzyme glycogen phosphorylase catalyzes the shortening and removal of chains and branches from glycogen to produce glucose-1-phosphate and then glucose-6-phosphate. Glycogenolysis is regulated through the activation of phosphorylase and its inhibitor, as well as the role of calcium in stimulating glycogen breakdown in muscles.
Reference Harper Illustrated book of Biochemistry
Applying laws of Thermodynamics to Biochemistry.
Diferent types of Reactions, exergonic and edergonic,
Illustrated explain of Role of ATP in our body,
Brief concept on ATP production and high energy phosphate,
ATP/ADP cycle and about Creatine Kinase
The electron transport chain is comprised of a series of enzymatic reactions within the inner membrane of the mitochondria, which are cell organelles that release and store energy for all physiological needs.
As electrons are passed through the chain by a series of oxidation-reduction reactions, energy is released, creating a gradient of hydrogen ions, or protons, across the membrane. The proton gradient provides energy to make ATP, which is used in oxidative phosphorylation.
The document summarizes the process of glycolysis. It discusses how glycolysis involves 10 steps divided into 3 stages. The first stage converts glucose to fructose 1,6-bisphosphate. The second stage cleaves this molecule into two 3-carbon fragments. The third stage oxidizes these fragments to pyruvate, producing ATP through substrate-level phosphorylation. Key intermediates like glucose-6-phosphate and 1,3-bisphosphoglycerate have properties that allow harvesting of energy to produce ATP. The document also notes how glycolysis traps glucose within cells and provides building blocks for biosynthesis.
This document summarizes several pathways involved in carbohydrate metabolism. It describes the hexose monophosphate pathway (HMP pathway), which provides an alternative route for glucose metabolism and is significant for biosynthesis of NADPH and pentose sugars. It does not consume or produce ATP. The document also summarizes the gamma amino butyrate (GABA) shunt, which converts glutamate to succinate via GABA. Finally, it provides an overview of glycogen metabolism, describing glycogen synthesis from glucose and glycogen breakdown into glucose.
Gluconeogenesis- Steps, Regulation and clinical significanceNamrata Chhabra
Gluconeogenesis- Thermodynamic barriers, substrates of gluconeogenesis, reciprocal regulation of glycolysis and gluconeogenesis, biological and clinical significance
The HMP shunt, also known as the pentose phosphate pathway or phosphogluconate pathway, is an alternative pathway to glycolysis and the TCA cycle for glucose oxidation. It is more anabolic in nature and concerned with biosynthesis of NADPH and pentoses. The pathway occurs in the cytosol of tissues involved in biosynthesis like the liver, adipose tissue, and erythrocytes. It is significant in generating NADPH and pentoses like ribose-5-phosphate. NADPH is important for biosynthesis of fatty acids, steroids, and antioxidant defense while pentoses are precursors for nucleic acid synthesis. Regulation involves inhibition of the first step by NADPH. Genetic deficiencies can
The document summarizes the urea cycle, which takes place in the liver and involves several enzymes that convert toxic ammonia produced from protein metabolism into urea that can be excreted by the kidneys. The cycle includes the enzymes carbamoyl phosphate synthetase, ornithine transcarbamoylase, argininosuccinate synthetase, argininosuccinate lyase, and arginase. Defects in the enzymes can lead to metabolic disorders where specific products accumulate, such as ammonia, ornithine, citrulline, or arginine. The cycle is regulated by factors like carbamoyl phosphate synthetase and levels of protein intake.
This document provides information about enzymes including their history, characteristics, classification, and mechanisms of action. Some key points:
- Enzymes are organic biocatalysts that accelerate chemical reactions by lowering the activation energy. They are not consumed by the reactions they catalyze.
- The term "enzyme" was first used in the 19th century to describe digestion processes. Important early discoveries included identifying enzymes responsible for starch digestion and fermentation.
- Enzymes are usually proteins but can also be RNA. They are highly specific and act as catalysts by lowering the activation energy of reactions through transition state stabilization.
- The International Union of Biochemistry and Molecular Biology (IUBMB)
It is an metabolic pathway of synthesis of glucose from non carbohydrate precursors like pyruvate, lactate, amino acid, glycerol etc. Main sites are liver and kidney. It uses enzymes from both cytosol and mitochondria.
Cholesterol biosynthesis is a multi-step process that begins with acetyl-CoA and occurs primarily in the liver and other tissues. Key steps include the conversion of HMG-CoA to mevalonate by the rate-limiting enzyme HMG-CoA reductase. Cholesterol can then be used for membrane structure, steroid hormone synthesis, or converted to bile acids which are secreted in the bile. Cholesterol levels are regulated by feedback inhibition of HMG-CoA reductase and uptake/secretion of cholesterol and bile acids. Statins lower cholesterol by inhibiting HMG-CoA reductase.
Glycogen is the storage form of carbohydrates in animals, analogous to starch in plants. Glycogen is synthesized from glucose through glycogenesis, which occurs predominantly in the liver and muscles, and stored glycogen is broken down to glucose through glycogenolysis. Glycogenesis is regulated by hormones like insulin, epinephrine, and glucagon that control intracellular cAMP levels and the phosphorylation state of glycogen synthase to convert it between its active and inactive forms.
This document discusses glycolysis, the pathway that breaks down glucose to pyruvate. Glycolysis occurs in the cytosol of cells and can proceed with or without oxygen. It is an important pathway for ATP generation. The document outlines the 10 steps of glycolysis, including an energy investment phase where ATP is used to phosphorylate glucose, and an energy generation phase where ATP is regenerated. Phosphofructokinase is identified as the rate-limiting step. The fate of pyruvate, the end product, depends on oxygen availability, leading to aerobic or anaerobic metabolism.
This document discusses carbohydrate metabolism and glycolysis. It begins by classifying carbohydrate metabolism into glycolysis, the Krebs cycle, the hexose monophosphate shunt, glycogenesis, glycogenolysis, and gluconeogenesis. It then provides details on glycolysis, including that it converts glucose to pyruvate or lactate, involving 10 reactions in 3 stages. Key enzymes and reactions in each stage are described. The document also discusses regulation of glycolysis and differences between hexokinase and glucokinase.
glycolysis.pdf for bscs for human nutrition and dieteticsjiyabhatti475
1) Glycolysis is the first pathway of glucose metabolism that breaks glucose down into pyruvate, producing a small amount of ATP.
2) Glycolysis involves several phosphorylation and oxidation-reduction reactions regulated by factors like insulin, ATP levels, and fructose 2,6-bisphosphate.
3) The breakdown of glucose via glycolysis is critical for producing energy in red blood cells and some microbes that lack mitochondria.
The document provides information on metabolic pathways including glycolysis, the citric acid cycle, and the electron transport chain. It begins with an overview of glycolysis, including its two phases and location in the cytoplasm. Key details are provided on the regulation of three glycolytic enzymes: hexokinase, PFK-1, and pyruvate kinase. The document then discusses the fates of pyruvate, including its conversion to acetyl-CoA and entry into the citric acid cycle or fermentation pathways. An overview of the citric acid cycle follows, along with its regulation and role in ATP production. The electron transport chain is then introduced, along with the structures and functions of its four complexes. In summary
To understand how the glycolytic pathway is converts glucose to pyruvate.
To understand conservation of chemical potential energy in the form of ATP and NADH.
To learn the intermediates, enzyme, and cofactors of the glycolytic pathway.
Carbohydrates are the sugars, starches and fibers found in fruits, grains, vegetables and milk products. Though often maligned in trendy diets, carbohydrates — one of the basic food groups — are important to a healthy diet.
Metabolism involves breaking down complex substances into simpler ones through catabolism and building them back up through anabolism. This releases energy, eliminates waste, and enables growth and functioning. Glycolysis is the first step of carbohydrate metabolism, where glucose is broken down into two pyruvate molecules through 10 enzyme-catalyzed reactions. This generates a small amount of ATP but produces NADH which feeds into downstream pathways like the TCA cycle to generate more ATP through oxidative phosphorylation. Key regulatory steps control the rate of glycolysis in response to energy demands and nutrient availability.
Metabolism is the network of chemical reactions that take place in living cells. It performs four main functions: obtaining energy, converting nutrients into macromolecules, assembling macromolecules, and degrading macromolecules. Metabolic pathways can be catabolic, anabolic, or amphibolic. Glycolysis converts glucose into pyruvate, generating a small amount of ATP. Pyruvate then undergoes oxidative decarboxylation to form acetyl-CoA, the entry point into the citric acid cycle. Diseases can impair glycolysis through deficiencies in enzymes like pyruvate kinase or disorders that cause lactic acidosis.
This document provides an overview of glycolysis. It begins by defining glycolysis as the pathway that converts glucose to pyruvate with production of ATP. It then discusses the specific reactions of glycolysis in three phases: the energy investment phase where ATP is used to phosphorylate glucose, the splitting phase where a 6-carbon molecule splits into two 3-carbon molecules, and the energy generation phase where ATP is produced. Key points include that glycolysis occurs in the cytoplasm and produces 2 ATP net per glucose molecule under anaerobic conditions, or up to 8 ATP net per glucose under aerobic conditions when the NADH produced is further oxidized in the mitochondria. The document also notes some regulation and applications of glycolysis.
Carbohydrate metabolism and its disorders.pdfshinycthomas
This document discusses carbohydrate metabolism pathways including glycolysis, the citric acid cycle, gluconeogenesis, and glycogen metabolism. It provides detailed information on glycolysis, including its definition, sites in the body, steps, energy production, oxidation of NADH, importance and functions. It also discusses glycogen metabolism including glycogenesis and glycogenolysis. The document concludes with sections on disorders of carbohydrate metabolism including pentosuria and galactosemia.
Glycolysis is the first step in the breakdown of glucose to extract energy through a series of reactions that split glucose into two three-carbon molecules called pyruvates. It occurs in the cytosol of cells and can be divided into three phases: an energy-requiring phase, splitting phase, and energy-releasing phase. Glycolysis produces two ATP molecules and reduces two NAD+ to NADH to maintain redox balance under anaerobic conditions. The pathway allows organisms to extract energy from glucose without oxygen.
1. Glycolysis is the breakdown of glucose to pyruvate with production of ATP. Glycolysis occurs in the cytoplasm and is the first step of carbohydrate metabolism.
2. The citric acid cycle (Krebs cycle) occurs in the mitochondria and involves the oxidation of acetyl CoA derived from pyruvate to carbon dioxide. This produces NADH and FADH2 to be used in the electron transport chain for ATP production.
3. Glycogenesis is the formation of glycogen from glucose-6-phosphate in the liver and muscle cells for energy storage. Glycogenolysis breaks down glycogen back to glucose-6-phosphate to regulate blood glucose levels.
The document discusses bioenergetics and cellular processes related to energy production. It begins by defining bioenergetics as the field concerning energy flow through living systems, including the study of cellular respiration and other metabolic pathways. It then provides an overview of glycolysis, discussing the two phases that convert glucose to pyruvate and produce ATP. The document also summarizes lactic acid fermentation, alcoholic fermentation, and the citric acid cycle, noting their roles in further oxidizing pyruvate to extract energy through ATP production. Real world examples of these processes in areas like cancer metabolism and food production are also briefly mentioned.
biochemistry of MSS prepared by Fikadu Seyoum Tola. This ppt essentially disc...fikaduseyoum1
biochemistry of MSS prepared by Fikadu Seyoum Tola. This ppt essentially discuss about collegen biosnthesis, defect and muscle energy metabolism with its regulations.
The prime cause and treatment of cancer somayeh zaminpira - sorush niknamianbanafsheh61
This meta-analysis research has gone through more than 200 studies from 1934 to 2016 to find the differences and similarities in cancer cells, mostly the cause. The most important difference between normal cells and cancer cells is how they respire. Normal cells use the sophisticated process of respiration to efficiently turn any kind of nutrient that is fat, carbohydrate or protein into high amounts of energy in the form of ATP. This process requires oxygen and breaks food down completely into harmless carbon dioxide and water. Cancer cells use a primitive process of fermentation to inefficiently turn either glucose from carbohydrates or the amino acid glutamine from protein into small quantities of energy in the form of ATP. This process does not require oxygen, and only partially breaks down food molecules into lactic acid and ammonia, which are toxic waste products. The most important result is that fatty acids or better told fats cannot be fermented by cells. This research mentions the role of ROS and inflammation in causing mitochondrial damage and answers the most important questions behind cancer cause and mentions some beneficial methods in preventing and treatment of cancer.
This document discusses metabolism of carbohydrates, proteins, and fats. It defines key terms like metabolism, catabolism, anabolism, and abnormal metabolism. It describes glycolysis as the breakdown of glucose to pyruvate, and the citric acid cycle as the further breakdown of pyruvate to carbon dioxide. Energy production through oxidative phosphorylation is also summarized. Abnormal carbohydrate metabolism like glycogen storage diseases and diabetes mellitus are briefly outlined.
The document discusses carbohydrate metabolism, focusing on glycolysis. It begins by outlining the major pathways of carbohydrate metabolism in animals, including glycolysis, glycogenesis/glycogenolysis, gluconeogenesis, the pentose phosphate pathway, and links to fatty acid and amino acid metabolism. The main text then focuses on glycolysis, describing it as an ancient pathway that converts glucose to pyruvate with the production of a small amount of ATP. Glycolysis proceeds in two stages: glucose phosphorylation and cleavage, followed by conversion of glyceraldehyde-3-phosphate to pyruvate with net ATP production. The fates of pyruvate depend on aerobic vs. anaerobic conditions in the organism.
Glycolysis and the citric acid cycle are the main pathways for glucose metabolism and energy production in cells. Glycolysis breaks down glucose into pyruvate, generating a small amount of ATP. Pyruvate can then enter the citric acid cycle in mitochondria to be further oxidized, with electrons being transferred to oxygen through the electron transport chain. This generates a proton gradient that is used by ATP synthase to produce the majority of ATP through oxidative phosphorylation. Various pathways like gluconeogenesis, the pentose phosphate pathway, and glycogen metabolism also interact with glycolysis and the citric acid cycle to regulate glucose and energy homeostasis in the body.
Similar to Overview of metabolism & glycolysis lec 2 4 (20)
The document discusses the metabolism of lipoproteins in the human body. It describes the main classes of lipoproteins - chylomicrons, very low-density lipoproteins (VLDL), low-density lipoproteins (LDL), and high-density lipoproteins (HDL) - and their functions in transporting lipids around the body. Specifically, it notes that chylomicrons carry dietary lipids from the intestines to tissues, VLDL transports endogenous triglycerides from the liver to tissues, and changes to these lipoproteins during metabolism are facilitated by various apolipoproteins. The metabolism of lipoproteins is important as improper levels can contribute to atherosclerosis.
DNA replication occurs through a semiconservative process where each parental DNA strand serves as a template for the synthesis of a new complementary strand. This results in two daughter molecules each composed of one original parental strand and one newly synthesized strand. In eukaryotes, replication occurs during S phase of the cell cycle. The major enzymes involved are DNA polymerases, helicases, and ligases which unwind, copy, and join the strands respectively. Errors are corrected by proofreading and repair mechanisms to maintain genomic integrity.
The document discusses the chemiosmotic hypothesis, which explains how ATP synthesis is coupled to the electron transport chain. It states that (1) as electrons move through complexes I, III, and IV of the electron transport chain, protons are pumped from the mitochondrial matrix to the intermembrane space, building a proton gradient. (2) This proton gradient provides the energy for ATP synthase (Complex V) to catalyze the phosphorylation of ADP to ATP. Specifically, protons reenter the matrix through ATP synthase, driving the rotation of its membrane domain and causing conformational changes that lead to ATP production.
Bioenergetics refers to cellular energy transformations where the chemical bond energy of fuels like glucose is transformed into ATP through oxidative phosphorylation. There are three main phases: 1) oxidation of fuels, 2) conversion of fuel oxidation energy into ATP's high-energy phosphate bonds, and 3) utilization of ATP's energy for cellular processes. The electron transport chain facilitates ATP production by transferring electrons from fuels like NADH and FADH2 through complexes in the mitochondrial inner membrane to ultimately reduce oxygen to water. This releases free energy used by ATP synthase to produce ATP from ADP and inorganic phosphate with a P:O ratio of 3:1 typically.
The document summarizes the urea cycle, which converts excess nitrogen from amino acid metabolism into urea that is excreted in urine. It describes the steps of the cycle, including the formation of carbamoyl phosphate and subsequent reactions to produce arginine and regenerate ornithine. Disorders of the cycle can cause toxic buildup of ammonia. Treatment may involve supplementing precursors like arginine or using drugs that conjugate with amino acids to enhance nitrogen excretion.
oxidation of alpha, beta fatty acid and unsaturated fatty acid mariagul6
This document summarizes fatty acid oxidation through beta-oxidation. It discusses how fatty acids are broken down into acetyl-CoA in the mitochondria, generating energy in the form of ATP. Key points covered include the carnitine shuttle transport system, reactions of beta-oxidation, and oxidation of odd-chain and unsaturated fatty acids. Deficiencies in carnitine or the carnitine shuttle enzymes can impair fatty acid breakdown.
The pentose phosphate pathway generates NADPH through two oxidative reactions catalyzed by glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase. Ribulose-5-phosphate is formed and can undergo reversible nonoxidative reactions to form other pentose and hexose phosphates, including ribose-5-phosphate used for nucleotide biosynthesis. The pathway provides NADPH for processes like glutathione reduction in red blood cells to reduce hydrogen peroxide levels that could otherwise damage red blood cells through oxidative stress. Key enzymes in the oxidative and nonoxidative phases interconvert sugar phosphates to balance NADPH and nucleotide production.
The passage summarizes the digestion, absorption, and transport of dietary lipids in the human body. Dietary triglycerides are partially digested in the mouth and stomach. In the small intestine, pancreatic enzymes and bile emulsify the lipids into micelles. The micelles' lipid components diffuse into intestinal cells and are repackaged into chylomicrons for transport through the lymphatic system and bloodstream. Chylomicrons deliver fatty acids to tissues where they provide energy or are stored as fat. Chylomicron remnants return to the liver to complete the process.
Regulation of translation or gene expression lec 33mariagul6
Gene expression is regulated through several mechanisms:
1. Transcription factors and RNA polymerase control whether genes are actively transcribed or not by binding to DNA and initiating mRNA synthesis. Different combinations of active genes in different cell types results in differential gene expression.
2. Histone acetylation and methylation can open or close chromatin, making DNA more or less accessible to transcription factors and affecting whether genes are expressed.
3. MicroRNAs can modulate gene expression after transcription by altering mRNA function through inhibition of translation, induction of degradation, or in rare cases stimulation of mRNA.
The transfer of electrons down the electron transport chain creates a proton gradient across the inner mitochondrial membrane, but this alone does not produce ATP. The chemiosmotic hypothesis explains how ATP is synthesized using this proton gradient. Specifically, as protons are pumped across the membrane at complexes I, III, and IV, a gradient forms. ATP synthase then uses the potential energy of protons flowing back through the membrane to phosphorylate ADP, producing ATP. Inhibitors like oligomycin block ATP synthase and prevent ATP production, tightly coupling electron transport to phosphorylation.
Genetic engineering is the process of manipulating genes to introduce desirable traits. It involves combining DNA from different organisms, such as inserting a gene for insulin into bacteria. The gene is inserted into a plasmid or virus vector and introduced into a host cell. This allows the production of proteins like insulin to treat diseases. While genetic engineering holds promise to treat diseases, some argue it could disrupt nature in unintended ways. Regulatory issues also exist regarding its applications and effects.
Replication begins at the origin of replication (oriC) and proceeds bidirectionally. It is semiconservative, meaning each parental DNA strand serves as a template for a new complementary strand. Specialized enzymes help unwind and copy the DNA, with DNA polymerase adding nucleotides to growing strands using DNA primers. DNA ligase then joins fragments together to complete replication. Errors are corrected through proofreading. Replication and repair mechanisms help preserve genetic information as cells divide.
Heme is an iron-containing porphyrin that is essential for hemoglobin function. Porphyrins are cyclic compounds formed from four pyrrole rings linked by methylene bridges that can bind metal ions. Heme synthesis primarily occurs in erythroid precursor cells in the bone marrow and liver cells, involving multiple enzymatic steps to convert the precursor uroporphyriinogen to protoporphyrin and insert iron.
Metabolism of essential and non essential amino acids 20mariagul6
This document summarizes the metabolism of essential and non-essential amino acids in humans. It explains that non-essential amino acids can be synthesized in the body, while essential amino acids cannot and must come from diet. It describes the two main pathways of amino acid metabolism as transamination and deamination. Transamination transfers amino groups between amino acids, while deamination removes amino groups to form ammonia. The carbon skeletons of amino acids can be broken down into seven key intermediates, determining if the amino acid is glucogenic, ketogenic, or both. Genetic defects in amino acid metabolism pathways can cause serious disease.
This document discusses porphyrias, which are rare inherited or acquired defects in heme synthesis that result in the accumulation and increased excretion of porphyrins or porphyrin precursors. It describes different types of porphyrias including chronic hepatic porphyria, acute hepatic porphyrias, and erythropoietic porphyrias. It also discusses the degradation of heme during erythrocyte destruction and the formation and elimination of bilirubin, as well as different types of jaundice including hemolytic, hepatocellular, and obstructive jaundice. Special consideration is given to jaundice in newborns.
Phenylketonuria is the most common inborn error of amino acid metabolism, caused by a deficiency of the enzyme phenylalanine hydroxylase, resulting in accumulation of phenylalanine and deficiency of tyrosine. Maple syrup urine disease is a rare disorder caused by a deficiency in the enzyme branched-chain alpha-keto acid dehydrogenase, which causes the amino acids leucine, isoleucine, and valine to accumulate, resulting in toxic effects and neurological issues. Alkaptonuria is a rare condition caused by a deficiency in homogentisic acid oxidase, leading to accumulation of homogentisic acid and symptoms of darkened urine, joint arthritis, and black pigmentation of
Glucogenic and ketogenic amino acids lec 20mariagul6
This document discusses ketogenic and glucogenic amino acids. It defines ketogenic amino acids as those whose catabolism yields ketone bodies, while glucogenic amino acids yield intermediates that can be used for gluconeogenesis to produce glucose. Leucine and lysine are provided as examples of exclusively ketogenic amino acids. Several metabolic defects affecting amino acid catabolism are also summarized, including phenylketonuria, maple syrup urine disease, albinism, homocystinuria, and alkaptonuria.
Protein digestion begins in the stomach through the actions of gastric juice containing hydrochloric acid and pepsin. Pepsin breaks down proteins into large polypeptides. In the small intestine, pancreatic proteases further break down the polypeptides into oligopeptides and amino acids. The pancreatic enzymes are released and activated through the hormones cholecystokinin and secretin. Enteropeptidase activates trypsin which then activates other proteases through a cascade. Aminopeptidases on the intestinal surface break oligopeptides into smaller peptides and free amino acids. These are absorbed into the bloodstream concluding digestion. Deficiencies in pancreatic function or celiac disease can impair protein digestion.
Bioenergetics and electron transport chain 24mariagul6
1. The electron transport chain uses energy released from electron transfers to pump protons across the inner mitochondrial membrane, creating a proton gradient.
2. ATP synthase uses the potential energy in this proton gradient to drive the phosphorylation of ADP to ATP.
3. In this way, the chemiosmotic hypothesis explains how the flow of electrons along the electron transport chain is coupled to ATP production, even though the two processes are physically separate.
This document discusses synthetic analogs of purines, pyrimidines, nucleosides, and nucleotides and their uses. Some key synthetic analogs discussed are 5-fluoro- or 5-iodouracil, 3-deoxyuridine, 6-thioguanine and 6-mercaptopurine, 5- or 6-azauridine, 5- or 6-azacytidine, and 8-azaguanine. These analogs are used in cancer chemotherapy as they can be incorporated into DNA and disrupt nucleic acid synthesis or base pairing. Other analogs like allopurinol and azathioprine are used to treat conditions like hyperuricemia, gout, and suppress
Introduction to AI for Nonprofits with Tapp NetworkTechSoup
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How to Add Chatter in the odoo 17 ERP ModuleCeline George
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ISO/IEC 27001, ISO/IEC 42001, and GDPR: Best Practices for Implementation and...PECB
Denis is a dynamic and results-driven Chief Information Officer (CIO) with a distinguished career spanning information systems analysis and technical project management. With a proven track record of spearheading the design and delivery of cutting-edge Information Management solutions, he has consistently elevated business operations, streamlined reporting functions, and maximized process efficiency.
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Date: May 29, 2024
Tags: Information Security, ISO/IEC 27001, ISO/IEC 42001, Artificial Intelligence, GDPR
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A workshop hosted by the South African Journal of Science aimed at postgraduate students and early career researchers with little or no experience in writing and publishing journal articles.
Main Java[All of the Base Concepts}.docxadhitya5119
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This presentation includes basic of PCOS their pathology and treatment and also Ayurveda correlation of PCOS and Ayurvedic line of treatment mentioned in classics.
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Odoo 17 CRM allows us to track why we lose sales opportunities with "Lost Reasons." This helps analyze our sales process and identify areas for improvement. Here's how to configure lost reasons in Odoo 17 CRM
2. Metabolism is the term used to describe the interconversion
of chemical compounds in the body, the pathways taken by
individual molecules, their interrelationships, and the
mechanisms that regulate the flow of metabolites through the
pathways. Metabolic pathways fall into three categories:
1. Anabolic pathways(Synthetic)
Synthesis of larger and more complex compounds from
smaller precursors—e.g, the synthesis of protein from amino
acids.
2. Catabolic pathways (Degradative)
Breakdown of larger molecules, commonly involving oxidative
reactions, they are exothermic, producing reducing
equivalents, and, mainly via the respiratory chain, ATP. e.g
break down of complex molecules, such as proteins,
polysaccharides, and lipids, to a few simple molecules, for
example, CO2, NH3 (ammonia), and water.
3. Amphibolic pathways
act as links between the anabolic and catabolic pathways, e.g,
the citric acid cycle.
3.
4. REGULATION OF METABOLISM
The pathways of metabolism must be coordinated
so that the production of energy or the synthesis
of end products meets the needs of the cell.
Furthermore, individual cells do not function in
isolation but are part of a community of
interacting tissues. Thus, a sophisticated
communication system has evolved to coordinate
the functions of the body. Regulatory signals that
inform an individual cell of the metabolic state of
the body as a whole include hormones,
neurotransmitters .These, in turn, influence
signals generated within the cell.
5. A. Signals from within the cell (intracellular)
e.g the rate of a pathway may be influenced by the availability of substrates.
These intracellular signals typically elicit rapid responses.
B. Communication between cells (intercellular)
Signaling between cells usually results in a response that is slower than is
seen with signals that originate within the cell. Communication between
cells can be mediated, e.g by forming gap junctions. Gap junctions are a
specialized intercellular connection that connect the cytoplasm of two cells,
which allows various molecules, ions and electrical impulses to directly pass
through a regulated gate between cells.
C. Second messenger systems
“Second messenger” molecules {so named because they intervene between
the original messenger (the neurotransmitter or hormone) and the ultimate
effect on the cell}are part of the cascade of events that translates hormone
or neurotransmitter binding into a cellular response.
e.g cyclic AMP, cyclic GMP
8. Aerobic Glycolysis:
• Pyruvate is the end product of glycolysis in cells with
mitochondria and an adequate supply of oxygen.
• This series of ten reactions, because oxygen is required to
reoxidize the NADH formed during the oxidation of
glyceraldehyde 3-phosphate.
• Aerobic glycolysis sets the stage for the oxidative
decarboxylation of pyruvate to acetyl CoA, a major fuel of
the TCA (or citric acid) cycle.
Anaerobic Glycolysis :
• pyruvate is reduced to lactate as NADH is oxidized to NAD+ This
conversion of glucose to lactate.
• it can occur without the participation of oxygen. Anaerobic
glycolysis allows the production of ATP in tissues that lack
mitochondria (for example, red blood cells) or in cells deprived
of sufficient oxygen.
9. GLUCOSE TRANSPORT
Glucose cannot diffuse directly into cells, but enters
by one of two transport mechanisms: a Na+
independent facilitated diffusion transport system or
Na+ monosaccharide cotransporter system.
1. Na+ independent facilitated diffusion transport
This system is mediated by a family of 14 glucose
transporters in cell membranes. They are designated
GLUT-1 to GLUT-14 (glucose transporter isoforms 1–
14). Extra cellular glucose binds to the transporter,
which then alters its conformation, transporting
glucose across the cell membrane.
10. • GLUT-3 is the primary glucose transporter in
neurons.
• GLUT-1 is abundant in erythrocytes and blood
brain barrier, but is low in adult muscle,
• GLUT-4 is abundant in adipose tissue and skeletal
muscle. [Note: The number of GLUT-4
transporters active in these tissues is increased
by insulin.
• GLUT-2 IN LIVER AND KIDNEY FOR BOTH IN AND
OUT GLUCOSE MOVEMENT
• GLUT-5 is unusual in that it is the primary
transporter for fructose (instead of glucose) in
the small intestine and the testes.
11. 2. Na+ monosaccharide cotransporter system
This is an energy-requiring process that
transports glucose “against” a concentration
gradient i.e from low glucose concentrations
outside the cell to higher concentrations within
the cell. This system is a carrier-mediated
process in which the movement of glucose is
coupled to the concentration gradient of Na+,
which is transported into the cell at the same
time. The carrier is a sodium-dependent–
glucose transporter or SGLT. This type of
transport occurs in the epithelial cells of the
intestine ,renal tubules.
12. Two phases of glycolysis
The conversion of glucose to pyruvate occurs in
two stages .The first five reactions of glycolysis
correspond to an energy investment phase in
which the phosphorylated forms of
intermediates are synthesized at the expense of
ATP.
The subsequent reactions of glycolysis
constitute an energy generation phase in which
a net of two molecules of ATP and 2 NADH are
formed by substrate-level phosphorylation per
glucose molecule metabolized.
13.
14.
15. 1. Phosphorylation of glucose
Phosphorylated sugar molecules do not readily
penetrate cell membranes, because there are no
specific transmembrane carriers for these
compounds, and because they are too polar to
diffuse through the lipid core of membranes.
Mammals have several isozymes of the enzyme
hexokinase that catalyze the phosphorylation of
glucose to glucose 6-phosphate.
Hexokinase has broad substrate specificity and is
able to phosphorylate several hexoses in addition
to glucose.
16.
17. 2. Isomerization of glucose 6-phosphate
The isomerization of glucose 6-phosphate to
fructose 6-phosphate is catalyzed by phospho
glucose isomerase
3. Phosphorylation of fructose 6-phosphate
The irreversible phosphorylation reaction
catalyzed by phospho - fructokinase-1 (PFK-1)
is the most important control point and the
rate-limiting and committed step of glycolysis
PFK-1 is controlled by the available
concentrations of the substrates ATP and
fructose 6- phosphate.
18.
19.
20. 4. Cleavage of fructose 1,6-bisphosphate
Aldolase cleaves fructose 1,6-bisphosphate to
dihydroxy acetone phosphate and glyceraldehyde
3-phosphate
5. Isomerization of dihydroxyacetone phosphate
Triose phosphate isomerase interconverts
dihydroxyacetone phosphate and glyceraldehyde
3-phosphate. Dihydroxy - acetone phosphate
must be isomerized to glyceraldehyde 3-
phosphate for further metabolism by the
glycolytic pathway. This isomerization results in
the net production of two molecules of glycer -
aldehyde 3-phosphate from the cleavage
products of fructose 1,6- bisphosphate.
21.
22. 6. Oxidation of glyceraldehyde 3-phosphate
The conversion of glyceraldehyde 3-phosphate to
1,3-bisphosphoglycerate by glyceraldehyde 3-
phosphate dehydrogenase is the first oxidation-
reduction reaction of glycolysis. Because there is
only a limited amount of NAD+ in the cell, the
NADH formed by this reaction must be reoxidized
to NAD+ for glycolysis to continue. Two major
mechanisms for oxidizing NADH are:
1) the NADH-linked conversion of pyruvate to
lactate (anaerobic)
2) oxidation of NADH via the respiratory chain
(aerobic)
23. 7. Synthesis of 1,3-bisphosphoglycerate (1,3-
BPG):
The oxidation of the aldehyde group of
glyceraldehyde 3-phosphate to a carboxyl
group is coupled to the attachment of Pi to
the carboxyl group. The high-energy
phosphate group at carbon 1 of 1,3-BPG
conserves much of the free energy produced
by the oxidation of glyceraldehyde 3-
phosphate. The energy of this high-energy
phosphate drives the synthesis of ATP in the
next reaction of glycolysis.
24. Synthesis of 2,3-bisphosphoglycerate (2,3-
BPG) in red blood cells:
Some of the 1,3-BPG is converted to 2,3-BPG
by the action of bisphosphoglycerate mutase
(see Figure). 2,3-BPG, which is found in only
trace amounts in most cells, is present at high
concentration in red blood cells (increases O2
delivery) .2,3-BPG is hydrolyzed by a
phosphatase to 3-phosphoglycerate, which is
also an intermediate in glycolysis .
25. 8. Synthesis of 3-phosphoglycerate producing
ATP
When 1,3-BPG is converted to 3-
phosphoglycerate, the high-energy phosphate
group of 1,3-BPG is used to synthesize ATP
from ADP. This reaction is catalyzed by
phosphoglycerate kinase.Because two
molecules of 1,3-BPG are formed from each
glucose molecule, this kinase reaction
replaces the two ATP molecules consumed by
the earlier formation of glucose 6-phosphate
and fructose 1,6-bisphosphate.
26. Shift of the phosphate group from carbon 3
to carbon 2
The shift of the phosphate group from carbon
3 to carbon 2 of phosphoglycerate by
phosphoglycerate mutase is freely reversible
27. 9. Dehydration of 2-phosphoglycerate
The dehydration of 2-phosphoglycerate by
enolase redistributes the energy within the 2-
phosphoglycerate molecule, resulting in the
formation of phosphoenolpyruvate (PEP),
which contains a highenergy enol phosphate.
10. Formation of pyruvate producing ATP
The conversion of PEP to pyruvate is catalyzed
by pyruvate kinase.The equilibrium of the
pyruvate kinase reaction favors the formation
of ATP
28. Reduction of pyruvate to lactate
Lactate, formed by the action of lactate
dehydrogenase, is the final product of
anaerobic glycolysis in eukaryotic cells.
The formation of lactate is the major fate for
pyruvate in lens and cornea of the eye, kidney
medulla, testes, leukocytes and red blood
cells, because these are all poorly vascularized
and/or lack mitochondria.
29.
30. Energy from glycolysis
• ATP consumed 2 moles
• ATP produced direct 4 moles
• ATP indirect (NADH/H) 6 moles
• Net ATPs = 10-2= 8 moles
• If anaerobic glycolysis 2 ATP moles
31. Lactate formation in muscle:
In exercising skeletal muscle, NADH
production exceeds the oxidative capacity of
the respiratory chain. This results in an
elevated NADH/NAD+ ratio, favoring reduction
of pyruvate to lactate. Therefore, during
intense exercise, lactate accumulates in
muscle, causing a drop in the intracellular pH,
potentially resulting in cramps.
32. Lactic acidosis:
Elevated concentrations of lactate in the
plasma, termed lactic acidosis, occur when
there is a collapse of the circulatory system,
such as in myocardial infarction, pulmonary
embolism, and uncontrolled hemorrhage, or
when an individual is in shock. The failure to
bring adequate amounts of oxygen to the
tissues results in impaired oxidative
phosphorylation and decreased ATP synthesis.
To survive, the cells use anaerobic glycolysis as
a backup system for generating ATP, producing
lactic acid as the endproduct.
33. REGULATION OF GLYCOLYSIS
During the well-fed state:
Decreased levels of glucagon and elevated levels
of insulin, such as occur following a carbohydrate-
rich meal, cause an increase in fructose 2,6-
bisphosphate and, thus, in the rate of glycolysis in
the Fructose 2,6-bisphosphate, therefore, acts as
an intracellular signal, indicating that glucose is
abundant.
During starvation:
Elevated levels of glucagon and low levels of
insulin, such as occur during fasting decrease the
intracellular concentration of hepatic fructose 2,6-
bisphosphate. This results in a decrease in the
overall rate of glycolysis and an increase in
gluconeogenesis.