Carbohydrate metabolism
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This document presents an overview of carbohydrate metabolism. It begins with an introduction and outlines the key pathways of glycolysis, the Krebs cycle, and the electron transport chain. It then describes how carbohydrates are broken down and the products that are generated in each step. Under aerobic and anaerobic conditions, pyruvate can be converted to lactate or enter the Krebs cycle. Each pathway generates ATP or electron carriers. In total, the breakdown of one glucose molecule can generate up to 38 ATPs. Finally, it lists factors that influence which pathways are used such as nutritional status, oxygen availability, and tissue type and provides references.
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Glycogenesis ---Sir Khalid (Biochem)
This document discusses glycogenesis and glycogenolysis. Glycogenesis is the process by which glucose is polymerized into glycogen in the liver and skeletal muscles. It involves phosphorylation of glucose, synthesis of UDP-glucose, addition of glucose units to glycogen by glycogen synthase, and branching of glycogen chains. Glycogenolysis is the breakdown of glycogen into glucose-1-phosphate. It involves cleavage of glycosidic bonds by glycogen phosphorylase and debranching enzyme. Glycogen levels are regulated by hormones like epinephrine, glucagon, and insulin which target glycogen phosphorylase and glycogen synthase.
Glycolysis and gluconeogenesis
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Gluconeogenesis
Gluconeogenesis is the synthesis of glucose from non-carbohydrate substrates like lactate, glycerol and certain amino acids. It occurs in the liver and kidneys when carbohydrate availability is low, such as during fasting or diabetes. While fatty acids can provide energy, glucose is still required by certain tissues and as a precursor for lactose production. Gluconeogenesis bypasses the irreversible steps of glycolysis using different enzymes and pathways that convert substrates like pyruvate and the Cori cycle transfers lactate from muscles to the liver for glucose synthesis. Gluconeogenesis is regulated both long-term through induction of enzymes by glucocorticoids and repression by insulin, and short-term through the
Carbohydrate Metabolism
Carbohydrate metabolism involves the different biochemical processes responsible for the formation, breakdown, and interconversion of carbohydrates in living organisms.
Gluconeogenesis
Gluconeogenesis is the synthesis of glucose from non-carbohydrate precursors like lactate, glycerol, glucogenic amino acids, and pyruvate. It mainly occurs in the liver and kidney cytosol. The key steps involve converting pyruvate to phosphoenolpyruvate and overcoming the regulation of two irreversible glycolysis reactions through four unique gluconeogenic enzymes. Gluconeogenesis is regulated by hormones like insulin and glucagon that control the activity of the rate-limiting enzymes: glucose-6-phosphatase, fructose-1,6-bisphosphatase, and pyruvate carboxylase.
Carbohydrate metabolism
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.
Glycogen metabolism
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.
Gluconeogenesis
Gluconeogenesis is the process by which glucose is synthesized from non-carbohydrate precursors like lactate, glycerol, and certain amino acids. It occurs primarily in the liver and involves bypassing the three irreversible steps of glycolysis through different enzymes. Key enzymes in gluconeogenesis include pyruvate carboxylase and PEP carboxykinase which catalyze reactions to bypass pyruvate kinase. Gluconeogenesis and glycolysis share certain intermediate compounds but are not simple reversals of each other due to different enzymatic pathways. Regulation of these two processes helps determine whether glucose or glycogen will be synthesized or broken down depending on the body's energy needs.
Recommended
Glycogenesis ---Sir Khalid (Biochem)
This document discusses glycogenesis and glycogenolysis. Glycogenesis is the process by which glucose is polymerized into glycogen in the liver and skeletal muscles. It involves phosphorylation of glucose, synthesis of UDP-glucose, addition of glucose units to glycogen by glycogen synthase, and branching of glycogen chains. Glycogenolysis is the breakdown of glycogen into glucose-1-phosphate. It involves cleavage of glycosidic bonds by glycogen phosphorylase and debranching enzyme. Glycogen levels are regulated by hormones like epinephrine, glucagon, and insulin which target glycogen phosphorylase and glycogen synthase.
Glycolysis and gluconeogenesis
For More Medicine Free PPT - http://playnever.blogspot.com/
For Health benefits and medicine videos Subscribe youtube channel - https://www.youtube.com/playlist?list=PLKg-H-sMh9G01zEg4YpndngXODW2bq92w
Gluconeogenesis
Gluconeogenesis is the synthesis of glucose from non-carbohydrate substrates like lactate, glycerol and certain amino acids. It occurs in the liver and kidneys when carbohydrate availability is low, such as during fasting or diabetes. While fatty acids can provide energy, glucose is still required by certain tissues and as a precursor for lactose production. Gluconeogenesis bypasses the irreversible steps of glycolysis using different enzymes and pathways that convert substrates like pyruvate and the Cori cycle transfers lactate from muscles to the liver for glucose synthesis. Gluconeogenesis is regulated both long-term through induction of enzymes by glucocorticoids and repression by insulin, and short-term through the
Carbohydrate Metabolism
Carbohydrate metabolism involves the different biochemical processes responsible for the formation, breakdown, and interconversion of carbohydrates in living organisms.
Gluconeogenesis
Gluconeogenesis is the synthesis of glucose from non-carbohydrate precursors like lactate, glycerol, glucogenic amino acids, and pyruvate. It mainly occurs in the liver and kidney cytosol. The key steps involve converting pyruvate to phosphoenolpyruvate and overcoming the regulation of two irreversible glycolysis reactions through four unique gluconeogenic enzymes. Gluconeogenesis is regulated by hormones like insulin and glucagon that control the activity of the rate-limiting enzymes: glucose-6-phosphatase, fructose-1,6-bisphosphatase, and pyruvate carboxylase.
Carbohydrate metabolism
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.
Glycogen metabolism
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.
Gluconeogenesis
Gluconeogenesis is the process by which glucose is synthesized from non-carbohydrate precursors like lactate, glycerol, and certain amino acids. It occurs primarily in the liver and involves bypassing the three irreversible steps of glycolysis through different enzymes. Key enzymes in gluconeogenesis include pyruvate carboxylase and PEP carboxykinase which catalyze reactions to bypass pyruvate kinase. Gluconeogenesis and glycolysis share certain intermediate compounds but are not simple reversals of each other due to different enzymatic pathways. Regulation of these two processes helps determine whether glucose or glycogen will be synthesized or broken down depending on the body's energy needs.
Glycolysis ppt
This document provides information about glycolysis, including:
1) Glycolysis involves the breakdown of glucose into pyruvate, producing 2 ATP and 2 NADH. There are 10 enzyme-catalyzed reactions in two stages.
2) Key regulatory enzymes include hexokinase, phosphofructokinase, and pyruvate kinase which control the flux of glycolysis.
3) Under anaerobic conditions, NADH is regenerated through lactic acid or ethanol fermentation to allow glycolysis to continue.
URONIC ACID PATHWAY
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.
Uronic acid pathway
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
Metabolism of glycogen
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.
Glycogenolysis
Glycogenolysis is the breakdown of glycogen into glucose-1-phosphate. It occurs in three steps:
1) Phosphorolysis by glycogen phosphorylase cleaves α-1,4 glycosidic linkages, producing glucose-1-phosphate until four glucose residues remain.
2) A debranching enzyme removes these four residue branches through two activities, producing linear chains of glucose residues.
3) Phosphoglucomutase converts glucose-1-phosphate to glucose-6-phosphate, which can then enter glycolysis to produce energy or be released as free glucose from the liver. Glycogenolysis is regulated by allosteric effectors, hormones like glucagon and
Glycogen metabolism
This document summarizes glycogen metabolism. Glycogen is the storage form of glucose found primarily in the liver and muscles. Glycogenesis is the synthesis of glycogen from glucose using enzymes like glycogen synthase. Glycogenolysis is the breakdown of glycogen into glucose, carried out by phosphorylase and debranching enzymes. The glucose is then converted to glucose-6-phosphate and can re-enter circulation from the liver or be used locally by tissues in glycolysis. Glycogen thus serves to maintain blood glucose levels and acts as a fuel reserve for muscles.
14 Glucogenesis
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
13 Biochemistry _ Glycolysis
Glycolysis is a catabolic pathway that breaks down glucose to extract energy. It occurs in 10 steps and involves 2 phases. In the first phase, energy is invested to phosphorylate and cleave glucose. In the second phase, the products are further broken down with a net generation of ATP. Glycolysis converts one glucose into two pyruvate molecules, produces 2 NADH, uses 2 ATP and generates a net of 2 ATP per glucose. This pathway is regulated by controlling the activity of three key enzymes: hexokinase, phosphofructokinase, and pyruvate kinase.
URONIC ACID PATHWAY
The glucuronic acid pathway is a quantitatively minor route of glucose metabolism. Like the pentose phosphate pathway, it provides biosynthetic precursors and inter-converts some less common sugars to ones that can be metabolized.
Citric acid cycle
The citric acid cycle (CAC) is a key metabolic pathway that occurs in the mitochondria of cells. It involves the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins to carbon dioxide. During each turn of the cycle, NAD+ and FAD are reduced to NADH and FADH2 to generate energy in the form of ATP through oxidative phosphorylation. Overall, the complete oxidation of one acetyl-CoA molecule in the CAC and respiratory chain produces 12 ATP molecules, capturing the energy from nutrients. The cycle plays a central role in cellular respiration and the production of energy.
Glycogen Metabolism
Glycogen Metabolism , synthesis , degradation ....
References : " Lippincott's Biochemistry " book. and of curse "Wikipedia, the free encyclopedia"
gluconeogenesis
Gluconeogenesis is the pathway by which organisms synthesize glucose from non-carbohydrate precursors like lactate, pyruvate, glycerol, and certain amino acids. This occurs mainly in the liver and to a lesser extent in the kidneys. While some steps are reversible versions of glycolysis, three irreversible steps of glycolysis are bypassed. Specifically, pyruvate is converted to oxaloacetate then phosphoenolpyruvate through carboxylation and decarboxylation reactions requiring ATP and GTP. This generates free glucose which is an important control point, as glucose-6-phosphate is typically further processed rather than released as free glucose except in a few tissues.
Gluconeogenesis
Gluconeogenesis is the production of glucose from non-carbohydrate sources through a complex series of metabolic pathways. It occurs primarily in the liver and kidney cytosol and produces approximately 1 kg of glucose per day, which is essential for brain function and as an energy source for muscles. The major precursors for gluconeogenesis are lactate, pyruvate, amino acids, glycerol, and propionate derived from the breakdown of proteins, fats, and certain metabolites. The pathways involved closely mirror glycolysis except for a few irreversible steps that are bypassed by alternative enzyme-catalyzed reactions in order to synthesize glucose from these precursors.
GLYCOGENESIS
The synthesis of glycogen from glucose (glycogenesis) involves multiple enzymatic steps that takes place in the cytosol. Glucose is first converted to glucose-6-phosphate by hexokinase or glucokinase in muscle and liver respectively. It is then converted to UDP-glucose which acts as the donor of glucose units. A glycogen primer, initiated by the enzyme glycogen synthase, is required to begin glycogen synthesis. Glycogen is then elongated through alpha-1,4 glycosidic linkages by glycogen synthase and branched through alpha-1,6 linkages by the branching enzyme glucosyltransferase. This leads to the formation of the branched glyc
Glycogen metabolism and its regulation
Glycogen is a highly branched polymer of glucose that serves as the primary storage form of glucose in the body. It is synthesized from glucose through glycogenesis, and broken down to glucose through glycogenolysis. Glycogen synthesis occurs mainly in the liver and muscle, and is regulated by hormones and metabolites to store glucose after meals and release it during fasting or exercise. Glycogen degradation provides glucose for energy and maintains blood glucose levels between meals.
Gluconeogenesis -
Gluconeogenesis is the formation of glucose from non-carbohydrate precursors and occurs primarily in the liver and kidneys. Key substrates include lactate, glycerol, and glucogenic amino acids. The process is regulated by substrate availability and key enzymes such as pyruvate carboxylase and phosphoenolpyruvate carboxykinase. Gluconeogenesis is critical for maintaining blood glucose levels during periods of fasting or low carbohydrate intake.
Digestion & absorption of carbohydrates
This document summarizes carbohydrate digestion in the human gastrointestinal tract. It describes how carbohydrates are broken down into smaller molecules by salivary and pancreatic amylases and intestinal disaccharidases and oligosaccharidases. The monosaccharides glucose, fructose and galactose that are produced are then absorbed into the bloodstream in the small intestine. Glucose absorption is an active process that utilizes sodium-glucose co-transporters, while fructose absorption occurs via facilitated diffusion. Factors that can influence carbohydrate absorption such as intestinal health, hormones and vitamins are also discussed.
Glucogenolysis
This document summarizes glycogenolysis, the breakdown of glycogen to glucose. Glycogen is the storage form of glucose in animals, found mainly in the liver and muscles. Glycogenolysis occurs in the liver and muscles to meet energy demands when blood glucose levels fall. It involves three main steps: 1) Glycogen phosphorylase cleaves glycogen molecules into glucose-1-phosphate. 2) A debranching enzyme further breaks down the glycogen molecules. 3) Glucose-1-phosphate is converted to glucose-6-phosphate and glucose to be used for energy. The process ultimately breaks down glycogen stores into glucose to regulate blood sugar levels.
Lipid metabolism-Physiology-First Year Pharmacy
Lipid metabolism involves the breakdown and synthesis of fats. Ingested triglycerides are broken down into fatty acids and monoglycerides in the intestine by pancreatic lipases. They are then absorbed and transported by chylomicrons. In cells, fatty acids undergo beta-oxidation to produce acetyl-CoA, which enters the Krebs cycle to generate energy. Excess acetyl-CoA can be used for ketogenesis or lipogenesis.
Gluconeogenesis and glycogenolysis
This document summarizes the metabolic pathways of gluconeogenesis and glycogenolysis. It explains that gluconeogenesis synthesizes glucose from non-carbohydrate precursors through a series of steps that are largely the reverse of glycolysis, with three bypass reactions. Glycogenolysis breaks down glycogen stores in the liver and muscle into glucose through cleavage of glucose monomers by glycogen phosphorylase and subsequent conversion to glucose-6-phosphate. Both pathways are regulated by hormones like glucagon and epinephrine.
Intro to Glucose Met. Glycolysis.pptx
Glycolysis is the breakdown of glucose into pyruvate to produce energy in the form of ATP. It occurs in the cytosol of cells. The end products of glycolysis are pyruvate, which enters the mitochondria for aerobic respiration, or lactate, produced under anaerobic conditions. Glycolysis generates 2 ATP per glucose molecule during anaerobic conditions and up to 38 ATP during aerobic respiration through subsequent pathways. Key enzymes regulate glycolysis through allosteric and covalent modification mechanisms. Deficiencies in glycolytic enzymes can cause genetic disorders like pyruvate kinase deficiency which leads to hemolytic anemia.
Glycolysis
Glycolysis is the central pathway for glucose degradation that produces energy in the form of ATP. During glycolysis, one molecule of glucose is broken down into two molecules of pyruvate, with the release of energy that is used to form two ATP and two NADH molecules. Glycolysis occurs in ten steps involving several enzymes and is the first metabolic pathway discovered, with the work of Louis Pasteur and others establishing its key reactions. The pathway allows for energy production under both aerobic and anaerobic conditions.
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Glycolysis ppt
This document provides information about glycolysis, including:
1) Glycolysis involves the breakdown of glucose into pyruvate, producing 2 ATP and 2 NADH. There are 10 enzyme-catalyzed reactions in two stages.
2) Key regulatory enzymes include hexokinase, phosphofructokinase, and pyruvate kinase which control the flux of glycolysis.
3) Under anaerobic conditions, NADH is regenerated through lactic acid or ethanol fermentation to allow glycolysis to continue.
URONIC ACID PATHWAY
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.
Uronic acid pathway
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
Metabolism of glycogen
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.
Glycogenolysis
Glycogenolysis is the breakdown of glycogen into glucose-1-phosphate. It occurs in three steps:
1) Phosphorolysis by glycogen phosphorylase cleaves α-1,4 glycosidic linkages, producing glucose-1-phosphate until four glucose residues remain.
2) A debranching enzyme removes these four residue branches through two activities, producing linear chains of glucose residues.
3) Phosphoglucomutase converts glucose-1-phosphate to glucose-6-phosphate, which can then enter glycolysis to produce energy or be released as free glucose from the liver. Glycogenolysis is regulated by allosteric effectors, hormones like glucagon and
Glycogen metabolism
This document summarizes glycogen metabolism. Glycogen is the storage form of glucose found primarily in the liver and muscles. Glycogenesis is the synthesis of glycogen from glucose using enzymes like glycogen synthase. Glycogenolysis is the breakdown of glycogen into glucose, carried out by phosphorylase and debranching enzymes. The glucose is then converted to glucose-6-phosphate and can re-enter circulation from the liver or be used locally by tissues in glycolysis. Glycogen thus serves to maintain blood glucose levels and acts as a fuel reserve for muscles.
14 Glucogenesis
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
13 Biochemistry _ Glycolysis
Glycolysis is a catabolic pathway that breaks down glucose to extract energy. It occurs in 10 steps and involves 2 phases. In the first phase, energy is invested to phosphorylate and cleave glucose. In the second phase, the products are further broken down with a net generation of ATP. Glycolysis converts one glucose into two pyruvate molecules, produces 2 NADH, uses 2 ATP and generates a net of 2 ATP per glucose. This pathway is regulated by controlling the activity of three key enzymes: hexokinase, phosphofructokinase, and pyruvate kinase.
URONIC ACID PATHWAY
The glucuronic acid pathway is a quantitatively minor route of glucose metabolism. Like the pentose phosphate pathway, it provides biosynthetic precursors and inter-converts some less common sugars to ones that can be metabolized.
Citric acid cycle
The citric acid cycle (CAC) is a key metabolic pathway that occurs in the mitochondria of cells. It involves the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins to carbon dioxide. During each turn of the cycle, NAD+ and FAD are reduced to NADH and FADH2 to generate energy in the form of ATP through oxidative phosphorylation. Overall, the complete oxidation of one acetyl-CoA molecule in the CAC and respiratory chain produces 12 ATP molecules, capturing the energy from nutrients. The cycle plays a central role in cellular respiration and the production of energy.
Glycogen Metabolism
Glycogen Metabolism , synthesis , degradation ....
References : " Lippincott's Biochemistry " book. and of curse "Wikipedia, the free encyclopedia"
gluconeogenesis
Gluconeogenesis is the pathway by which organisms synthesize glucose from non-carbohydrate precursors like lactate, pyruvate, glycerol, and certain amino acids. This occurs mainly in the liver and to a lesser extent in the kidneys. While some steps are reversible versions of glycolysis, three irreversible steps of glycolysis are bypassed. Specifically, pyruvate is converted to oxaloacetate then phosphoenolpyruvate through carboxylation and decarboxylation reactions requiring ATP and GTP. This generates free glucose which is an important control point, as glucose-6-phosphate is typically further processed rather than released as free glucose except in a few tissues.
Gluconeogenesis
Gluconeogenesis is the production of glucose from non-carbohydrate sources through a complex series of metabolic pathways. It occurs primarily in the liver and kidney cytosol and produces approximately 1 kg of glucose per day, which is essential for brain function and as an energy source for muscles. The major precursors for gluconeogenesis are lactate, pyruvate, amino acids, glycerol, and propionate derived from the breakdown of proteins, fats, and certain metabolites. The pathways involved closely mirror glycolysis except for a few irreversible steps that are bypassed by alternative enzyme-catalyzed reactions in order to synthesize glucose from these precursors.
GLYCOGENESIS
The synthesis of glycogen from glucose (glycogenesis) involves multiple enzymatic steps that takes place in the cytosol. Glucose is first converted to glucose-6-phosphate by hexokinase or glucokinase in muscle and liver respectively. It is then converted to UDP-glucose which acts as the donor of glucose units. A glycogen primer, initiated by the enzyme glycogen synthase, is required to begin glycogen synthesis. Glycogen is then elongated through alpha-1,4 glycosidic linkages by glycogen synthase and branched through alpha-1,6 linkages by the branching enzyme glucosyltransferase. This leads to the formation of the branched glyc
Glycogen metabolism and its regulation
Glycogen is a highly branched polymer of glucose that serves as the primary storage form of glucose in the body. It is synthesized from glucose through glycogenesis, and broken down to glucose through glycogenolysis. Glycogen synthesis occurs mainly in the liver and muscle, and is regulated by hormones and metabolites to store glucose after meals and release it during fasting or exercise. Glycogen degradation provides glucose for energy and maintains blood glucose levels between meals.
Gluconeogenesis -
Gluconeogenesis is the formation of glucose from non-carbohydrate precursors and occurs primarily in the liver and kidneys. Key substrates include lactate, glycerol, and glucogenic amino acids. The process is regulated by substrate availability and key enzymes such as pyruvate carboxylase and phosphoenolpyruvate carboxykinase. Gluconeogenesis is critical for maintaining blood glucose levels during periods of fasting or low carbohydrate intake.
Digestion & absorption of carbohydrates
This document summarizes carbohydrate digestion in the human gastrointestinal tract. It describes how carbohydrates are broken down into smaller molecules by salivary and pancreatic amylases and intestinal disaccharidases and oligosaccharidases. The monosaccharides glucose, fructose and galactose that are produced are then absorbed into the bloodstream in the small intestine. Glucose absorption is an active process that utilizes sodium-glucose co-transporters, while fructose absorption occurs via facilitated diffusion. Factors that can influence carbohydrate absorption such as intestinal health, hormones and vitamins are also discussed.
Glucogenolysis
This document summarizes glycogenolysis, the breakdown of glycogen to glucose. Glycogen is the storage form of glucose in animals, found mainly in the liver and muscles. Glycogenolysis occurs in the liver and muscles to meet energy demands when blood glucose levels fall. It involves three main steps: 1) Glycogen phosphorylase cleaves glycogen molecules into glucose-1-phosphate. 2) A debranching enzyme further breaks down the glycogen molecules. 3) Glucose-1-phosphate is converted to glucose-6-phosphate and glucose to be used for energy. The process ultimately breaks down glycogen stores into glucose to regulate blood sugar levels.
Lipid metabolism-Physiology-First Year Pharmacy
Lipid metabolism involves the breakdown and synthesis of fats. Ingested triglycerides are broken down into fatty acids and monoglycerides in the intestine by pancreatic lipases. They are then absorbed and transported by chylomicrons. In cells, fatty acids undergo beta-oxidation to produce acetyl-CoA, which enters the Krebs cycle to generate energy. Excess acetyl-CoA can be used for ketogenesis or lipogenesis.
Gluconeogenesis and glycogenolysis
This document summarizes the metabolic pathways of gluconeogenesis and glycogenolysis. It explains that gluconeogenesis synthesizes glucose from non-carbohydrate precursors through a series of steps that are largely the reverse of glycolysis, with three bypass reactions. Glycogenolysis breaks down glycogen stores in the liver and muscle into glucose through cleavage of glucose monomers by glycogen phosphorylase and subsequent conversion to glucose-6-phosphate. Both pathways are regulated by hormones like glucagon and epinephrine.
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Intro to Glucose Met. Glycolysis.pptx
Glycolysis is the breakdown of glucose into pyruvate to produce energy in the form of ATP. It occurs in the cytosol of cells. The end products of glycolysis are pyruvate, which enters the mitochondria for aerobic respiration, or lactate, produced under anaerobic conditions. Glycolysis generates 2 ATP per glucose molecule during anaerobic conditions and up to 38 ATP during aerobic respiration through subsequent pathways. Key enzymes regulate glycolysis through allosteric and covalent modification mechanisms. Deficiencies in glycolytic enzymes can cause genetic disorders like pyruvate kinase deficiency which leads to hemolytic anemia.
Glycolysis
Glycolysis is the central pathway for glucose degradation that produces energy in the form of ATP. During glycolysis, one molecule of glucose is broken down into two molecules of pyruvate, with the release of energy that is used to form two ATP and two NADH molecules. Glycolysis occurs in ten steps involving several enzymes and is the first metabolic pathway discovered, with the work of Louis Pasteur and others establishing its key reactions. The pathway allows for energy production under both aerobic and anaerobic conditions.
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3) Other monosaccharides like fructose and galactose can enter glycolysis after
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Carbohydrates are the largest source of calories and are broken down into glucose, which is the main carbohydrate used in metabolism. Glucose is absorbed into the bloodstream and transported to tissues like muscle where it is either used for energy or stored as glycogen. Carbohydrate digestion begins in the mouth and small intestine where enzymes break starches and sugars into glucose and other monosaccharides that can be absorbed. Glucose is then regulated through various pathways including glycolysis, the citric acid cycle, and oxidative phosphorylation to produce energy in the form of ATP.
Carbohydrate metabolism
The document discusses glycolysis, which is the breakdown of glucose to pyruvate with production of ATP. It occurs in the cytosol of cells and can proceed with or without oxygen present. Under anaerobic conditions, pyruvate is reduced to lactate, while in aerobic conditions pyruvate enters the citric acid cycle in mitochondria to be fully oxidized to CO2 and H2O. Glycolysis is tightly regulated by feedback inhibition and is a key energy producing process, especially under low oxygen conditions like in muscle during exercise. The citric acid cycle further oxidizes acetyl-CoA produced from pyruvate to generate more ATP through oxidative phosphorylation.
Central Metabolism
1. The document discusses carbohydrate metabolism, including glycolysis, the citric acid cycle (TCA cycle), gluconeogenesis, glycogenesis, and glycogenolysis.
2. Glycolysis converts glucose to pyruvate, producing ATP and NADH. The TCA cycle further oxidizes pyruvate, producing more ATP, NADH, and FADH2.
3. Gluconeogenesis produces glucose from non-carbohydrate sources. Glycogenesis and glycogenolysis involve the synthesis and breakdown of glycogen for glucose storage and mobilization.
A Classroom Lecture on Cell Metabolism. By: Dr. Ozair Chaudhry
The document summarizes cellular glycolytic pathways and energy production in cells. It discusses four stages: 1) glycolysis and fermentation, which produces 2 ATP per glucose molecule; 2) pyruvate oxidation in the mitochondria, which produces more NADH; 3) the Krebs cycle, which fully breaks down glucose and produces NADH, FADH2, and 1 ATP; 4) electron transport and chemiosmosis, where electrons are transferred to create a proton gradient used by ATP synthase to produce approximately 32 ATP per pair of NADH/FADH2 molecules. In total, the complete breakdown of one glucose molecule typically yields about 36 ATP.
Glycolysis 2nd year MBBS 2024.pdf
The document provides details about the course content and modules for the year 2024. It includes 5 modules covering topics like digestion and metabolism of carbohydrates, lipids, proteins, nucleotides and hormones. Each module includes course content that will be taught as well as related practical experiments. For example, module 1 on GIT includes topics on carbohydrate digestion and metabolism, and practicals like serum amylase estimation and oral glucose tolerance test. The document thus provides an overview of the topics and practical experiments included in each module for the course in the year 2024.
Carbohydrate & lipid Metabolism_food Sci.pdf
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
1. COH met1 .pptx
This document provides an overview of carbohydrate metabolism. It discusses:
1) The digestion of carbohydrates in the mouth, stomach, and small intestine by enzymes like amylase and disaccharidases into monosaccharides like glucose, galactose, and fructose.
2) The absorption of monosaccharides into the bloodstream and their fate in tissues through pathways like glycolysis and glycogenesis.
3) Glycolysis, the breakdown of glucose to pyruvate with production of ATP, and its regulation and clinical significance.
4.2 glycolysis & TCA cycle.ppt
The document discusses glycolysis and the citric acid cycle. Glycolysis involves 10 steps that break down glucose and generate a small amount of ATP without oxygen. The citric acid cycle is a series of chemical reactions in the mitochondria that further oxidizes pyruvate from glycolysis to extract more chemical energy. It involves 8 steps that produce carbon dioxide, NADH, and FADH2 to fuel the electron transport chain for oxidative phosphorylation to generate large amounts of ATP. Both pathways are tightly regulated and provide precursors for other biological processes.
Integration of metabolism
This document summarizes key aspects of metabolism integration. It discusses the major macronutrients and their roles in energy production and storage. The major metabolic pathways are described, including their junction points and regulatory enzymes. Specific pathways for glucose, fatty acids, and amino acids are explained. The roles of the liver in metabolic integration and regulation by hormones like insulin and glucagon are highlighted.
Carbo metabolism
Glycolysis is the metabolic pathway that converts glucose into pyruvate and produces a small amount of ATP. It occurs in the cytoplasm of cells and can function aerobically or anaerobically. During aerobic glycolysis, pyruvate is further oxidized to produce more ATP. During anaerobic glycolysis, pyruvate is converted to lactate, producing less ATP. The citric acid cycle is a series of chemical reactions in the mitochondria that completes the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins to produce carbon dioxide, water, and ATP through oxidative phosphorylation. It is also known as the Krebs cycle or TCA cycle. It is a key step
Cell Respiration APBio
The document summarizes glucose metabolism, which occurs in two stages. Glycolysis breaks down glucose in the cytoplasm, yielding pyruvate and generating 2 ATP per glucose. Cellular respiration then breaks down pyruvate in mitochondria, using oxygen to generate 32-34 more ATP via the Krebs cycle, electron transport chain, and chemiosmosis. The overall reaction yields 38 ATP from each glucose molecule.
Similar to Carbohydrate metabolism (20)
8_Metabolism,_catabolism_of_carbohydrates,_lipids_and_propteins.ppt
8_Metabolism,_catabolism_of_carbohydrates,_lipids_and_propteins.ppt
A Classroom Lecture on Cell Metabolism. By: Dr. Ozair Chaudhry
A Classroom Lecture on Cell Metabolism. By: Dr. Ozair Chaudhry
Carbohydrate metabolism
- 1. Presented by: HACKMAN, DESMOND PAA KWESI (BSc Nutrition & Food Sci., MSc Dietetics, Student Dietitian) College of Health Sciences University of Ghana, Legon
- 2. Introduction Glycolysis Krebs’ (Tricarboxylic acid) Cycle Electron Transport Chain/Oxidative Phosphorylation Total ATP Generation Factors Influencing CHO Metabolism References
- 3. Cn(H2O)n digestion monosaccharides C6H12O6 is the principal product of almost all digestible CHO; main fuel for energy. After absorption: glucose G6P; destined to follow one of these: - Glycolysis - Kreb’s Cycle - Pentose Phosphate Pathway - Glycogenolysis - Glucogenesis - Gluconeogenesis catabolic anabolic
- 5. Under aerobic conditions: Under anaerobic conditions: Lactate Dehydrogenase O C C CH3 O O O C HC CH3 OH O NADH + H+ NAD+ pyruvate lactate In aerobic conditions, the acetyl-CoA produced enters the TCA. However, in low O2 tension or ‘O2 debt’, such as during intense exercises, the muscle & RBC generate lactate from pyruvate. Increased lactic acid causes fatigue & cramps. If it occurs in the myocardium due to coronary thrombosis, it could have damaging effect on the heart.
- 6. Each produces 1ATP, 3NADH and 1FADH2 Thus for 1C6H12O6 2ATP, 6NADH and 2FADH2
- 7. Series of redox reactions in the mitochondria NADH and FADH2 produced in TCA & Glycolysis donate their electrons to a series of electron accepting compounds found on the inner membrane of the mitochondrion. NADH and FADH2 passes their electrons to 3 and 2 acceptor molecules respectively. Each transfer generate a proton electrochemical gradient which powers: ADP+Pi ATP Thus: 1NADH = 3ATPs 1FADH2 = 2ATPs
- 8. NADH FADH2 Direct ATP Glycolysis 2 - 2 (net) PDH (Pyruvate to Acetyl CoA) 2 - - TCA 6 2 2 Sub Total 10 2 4 TOTAL ATP = 10(3) + 2(2) + 4 = 38 ATPs Not all these 38ATPs are realised due to: Losses such as the cost of moving Pyruvate, Phosphate, ADP into the mitochondria. All are actively transported using carriers which utilise the stored energy in the proton electrochemical gradient.
- 9. Pathways depend on: Nutritional Status ◦ Glycogenolysis predominant in starvation & untreated DB. ◦ Glycogenesis predominant in fed state. ◦ Supply of adequate B-vitamins & minerals (Fe2+, Fe3+, Mg2+ ) ◦ Alcohol intake Oxygen Status ◦ In adequate O2, TCA is activated. ◦ When demand exceeds supply, glycolysis is activated in active muscle Tissue ⁄ cell type ◦ In tissue damage or Fatty acid synthesis, PPP is activated. ◦ Mature RBCs lack mitochondria & solely depend on glycolysis for energy.
- 10. Adjimani, J.P.(2006). MOLECULES OF LIFE: Energetics And Metabolism At A Glance. First edition. Beno Publications, N.T., Accra. Pp 26-40. Lehninger, M.M., Nelson, D.L. and Cox (2005). Principles of Biochemistry. Fourth edition. Worth Publishers, U.S.A. Pp 524-526.