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Side A ------ Side B Metabolism ------ The sum total of all the chemcial reactions that go on in living cells. Energy metabolism includes all the reactions by which the body obtains and spends energy from food. Example: Nutrients provide the body with FUEL and follows them through a series of reactions that release energy from their chemical bonds. As the bonds break, they release energy in a controlled version of the process by which wood burns in a fire. Energy metabolism ------ All of the chemical reactions through which the human body acquires and spends energy from food Anabolism ------ Small compounds joined together to make largers ones; energy must be used in order to do this Ana = up Catabolism ------ Larger compounds BROKEN down into smaller ones; energy is RELEASED kata = down Coupled reactions ------ Energy released from the breakdown of a large compounds is used to drive other reactions ATP ------ Adenosine triphosphate; energy currency of the body -- produced when large compounds are broken down ATP is used to make large compounds from smaller ones. Ribosomes ------ Cellular machinery used to make proteins Mitochondria ------ Where energy is derived from fat, CHO, protein via TCA cycle, electron transport chain Coenzyme ------ Complex organic molecules that work with enzymes to facilitate the enzymes' activity. Many coenzymes have B vitamins as part of their structures. co = with Cofactor ------ The general term for substances that facilitate enzyme action is cofactors; they include both organic coenzymes such as vitamins and inorganic substances such as minerals Enzymes ------ Protein catalysts - proteins that facilitate chemical reactions without being changed in the process Metalloenzyme ------ Enzymes that contain one or more minerals as part of their structure BREAKING DOWN NUTRIENTS FOR ENERGY CHO (Carbohydrate) ------ CHO - glucose (6 carbons) BREAKING DOWN NUTRIENTS FOR ENERGY Fat ------ TG's - glycerol (3 carbons) + fatty acid (typically 18 carbons) BREAKING DOWN NUTRIENTS FOR ENERGY Protein ------ Protein - amino acids 2C-N, 3C-N, or 5C-N BREAKING DOWN NUTRIENTS FOR ENERGY New Compounds ------ Pyruvate (3 carbons) Acetyl CoA (2 carbons) GLUCOSE BREAKDOWN ------ CHO - glucose (6 carbons) - pyruvate (3 carbons) GLUCOSE BREAKDOWN With oxygen present = aerobic ------ Glucose (6C) - pyruvate (3C) - acetyl CoA (2C) - TCA cycle GLUCOSE BREAKDOWN With inadequate oxygen present = anaerobid (during strenous exercise) ------ Glucose (6C) - Pyruvate (3C) - Lactic acid GETTING RID OF LACTIC ACID Cory Cycle (liver repackages lactic acid as glucose) ------ Glucose (6C) - Pyruvate (3C) - Lactic acid - liver - glucose - back to blood - muscles (stored as glycogen) FAT BREAKDOWN Trigycerides ------ TG's - 3 fatty acids + glycerol FAT BREAKDOWN TG's - 3 fatty acids + glycerol Glycerol may be convered to ------ glucose or pyruvate depending on the cells needs; glucose is made if the blood glucose is low; pyruvate is made if energy is needed (will be broken down further in the TCA cycle) FAT BREAKDOWN TG's - 3 fatty acids + glycerol Fatty acids may be converted to ------ acetyl CoA and proceeds through TCA cycle; requires oxygen to do this (an aerobic process) FAT BREAKDOWN TG's - 3 fatty acids + glycerol Can you make glucose from fatty acids? ------ NO!!!!! PROTEIN BREAKDOWN Use of protein depends upon ------ cells needs and availablity of glucose Note: before amino acids maybe used, they must be deaminateed (nitrogen group removed) PROTEIN BREAKDOWN If glucose is needed.... ------ Protein - amino acid (deaminated) - glucose (Glucose is used by the brain, red blood cells) PROTEIN BREAKDOWN If energy is needed and glucose level is adequate.... ------ Protein - amino acid (deaminated) - glucose - pyruvate - aceytl CoA - TCA cycle Note: Some amino acids enter pathway and are converted to acetyl CoA, some amino acids enter the TCA cycle directly. PROTEIN BREAKDOWN Deamination ------ amino acic - keto acid (NH3) keto acid - non-essential amino acid (NH3) PROTEIN BREAKDOWN Transamination ------ A method for making non-essential amino acids; B6 needed for this process amino acid A + keto acid B = keto acid A = amino acid B GETTING RID OF AMMONIA PRODUCED FROM DEAMINATION Urea cycle ------ Ammonia is toxic; must be converted to nontoxic compound immediately; liver packages ammonia as UREA; kidneys excrete UREA High protein intake creates more work for kidneys; if eating high protein diet increase water intake to keep urea soluble ELECTRON TRANSPORT CHAIN (an aerobic process, requires oxygen) Process? ------ 1. Once acetyl CoA (2 carbon) enters the TCA cycle it quickly combines with a 4 carbon compound to create a 6 carbon compound 2. 2 carbons are lost during one turn of the cycle -- they are lost as CO2 3. There are also a number of HYDROGENS that are pulled off compounds and transferred to NAD which carries hydrogens 4. These HIGH ENERGY HYDROGEN atoms (high energy since they desperately want to combine with another molecule/atom so there will be 2 shared electrons) are transferred to NAD (niacin) and FAD (riboflavin) to electron transport chain 5.At the electron transport chain, HIGH ENERGY HYDROGENS (electrons) are take down a series of three little (waterfall) reactions to harness this energy -- ATP's are produced in this series of reactions FEASTING What happens to excess CHO's? ------ 1. CHO's used first to replenish glycogen stores 2. Extra is converted to fat CHO - glucose - pyruvate - acetyl CoA - fatty acids OR CHO - glucose - gylcerol + (see notes) FEASTING What happens to excess Fat? ------ Triglycerides stored directly into fat tissues, no breakdown required (except for chylomicron formation in GI) FEASTING What happens to excess protein? ------ 1. Dispose of Nitrogen group first via deamination 2. keto acid (amino acid minus nitrogen group) may enter metabolic pathway at pyruvate, acetyl CoA stage - acetyl CoA - fatty acids - TG's *Some protein will be used to replenish glycogen stores FASTING What happens if you fast less than 24 hours? ------ Will use up glycogen stores in liver and muscle tissue FASTING What happens if you fast LONGER than 24 hours, but less than 3-4 days? ------ Will begin gluconeogenesis using muscle tissue protein to generate new glucose (about 90% of glucose supplied by breaking down muscle tissue; fat (via glycerol) contributes only 10%) FASTING What happens if you fast LONGER THAN 3-4 DAYS? ------ Body shifts to KETOSIS to preserve muscle tissue; ketone bodies are 2 acetyl CoA' stuck together; some brain tissue is able to use ketone bodies for energy instead of glucose, which helps to preserve muscle tissue FAD DIETS Fad diets which promote eating only protein and fat will result in... ------ KETOSIS after 24 hours of diet ALCOHOL AND NUTRITION Historical findings show humans have used alcohol for over... ------ 5000 years ALCOHOL AND NUTRITION; Biochemisty ethanol ------ alcohol in fermented beverages Fuel ------ Compounds that cells can use for energy. The major fuels include glucose, fatty acids, and amino acids; other fuels include ketone bodies, lactic acid, glycerol and alcohol. Photosynthesis ------ The process by which green plants use the sun's energy to make carbohydrates from carbon dioxide and water. photo = light synthesis = put together (making) Name one of the body's high-energy molecules, and describe how it is used. ------ ATP (adenosine triphosphate) is a common high-energy compound composed of a purine (adenine), a sugar (ribose) and three phosphate groups. During digestion the energy-yielding nutrients - carbohydrates, lipids, and proteins - are broken down to glucose (and other monosaccharides), glycerol, fatty acids, and amino acids. Aided by enzymes and coenzymes, the cells used these products of digestion to build more complex compounds (anabolism) or break them down further to RELEASE ENERGY (Catabolism). THE ENERGY RELEASED DURING CATABOLISM MAY BE CAPTURED BY HIGH ENERGY COMPOUNDS SUCH AS ATP. What are the coenzymes, and what service do they provide in metabolism? ------ MEtabolic reactions almost always require enzymes to facilitate their action. In many cases, the enzymes need assistants to help them. Enzyme helpers are called coenzymes. Coenzymes are complex organic molecules that associate closely with most enzymes, but are not proteins themselves. Without its coenzyme, an enzyme cannot function. Name the four basic units, derived from foods, that are used by the body in metabolic transformations. How many carbons are in the "backbones" of each? ------ Glucose - 6 carbons Glycerol - 3 carbons Fatty acid - even number of carbons (commonly 16 or 18) Amino acid - 2, 3 or more carbons with a Nitrogen attached Define aerobic and nonaerobic metabolism. How does insufficient oxygen influence metabolism? ------ aerobic - requiring oxygen anaerobic - not requiring oxygen an = not Anaerobic pathway yield energy quickly, but cannon be sustaned for long - a couple of minutes at most. You would use this type of pathway during a sprint. Conversely, the aerobic pathways produce energy more slowly, because they can be sustaned for long period of time, their total energy yield is greater. This is the pathway you use most often, even at rest. How does the body dispose of excess nitrogen? ------ The liver continuously produces small amounts of ammonia in deamination reactions (removing nitrogen from amino acids). Some of this ammonia provides the nitrogen needed for the synthesis of nonessential amino acids. The liver quickly combines any remaining ammonia with carbon dioxide to make urea, a much less toxic compound. The liver releases the urea into the bloodstream and it is taken up and excreted by the kidneys. Summarize the main steps in the metabolism of glucose, glycerol, fatty acids and amino acids. ------ The digestion of carbohydrates yields glucose (and other momosaccharides): some is stored as glycogen, and some is broken down to pyruvate and acetal CoA to provide energy. The acetyl CoA can then enter the TCA cycle and electron transport chain to provide more energy. The digestion of fat yields glycerol and fatty acids; some are reassembled nd stored as fat, and others are broken down to acetyl CoA, which can enter the TCA cycle and electron transport chain to provide energy. The digestion of protein yields amino acids, most of which are used to build body protein or other nitrogen-containing compounds, but some amino acids may be broken down through the same pathways as glucose to provide energy. Other amino acids enter directly into the TCA cycle, and these, too, can be broken down to yield energy. In summary, although carbohydrate, fats and protein enter the TCA cycle by different routes, the final pathways are common to all energy-yielding nutrients. Describe how a surplus of the three energy nutrients contributes to body fat stores. ------ ALL EXCESS NUTRIENTS STORED AS FAT!!! Carbohydrate - broken down to glucose - used for liver and muscle glycogen stores - excess stored as FAT Fat - broken down to fatty acids - stored directly as FAT Protein - broken down to amino acids - used for body proteins - some loss of nitrogen in urine (urea) and then excess stored as FAT What adaptations does the body make during a fast? ------ *Increasing the breakdown of fat to provide energy for most of the cells *Using glycerol and amino acids to make glucose for the red blood cells and central nervous system *Producing keytones to fuel the brain *Supressing appetite and slowing metabolism. All these measures conserve energy and minimize loses. What are ketone bodies? ------ Ketone bodies are compounds produced during the imcomplete breakdown of fat when glucose is not available. Ketosis is a sign that the body's chemisty is going awry; Ketosis is the body's way to use its fats stores to fuel the brain by using ketones as an alternature fuel source. The brain prefers glucose. Define ketosis ------ An undesirably high concentration of ketone bodies in the blood and urine. Ketosis is the body's way to use its fats stores to fuel the brain by using ketones as an alternature fuel source, when glucose is limited (during starvation). Distinguish between a loss of fat and a loss of weight, and describe how each might happen. ------ Weight loss can be caused by shrinkage in the mass of organ tissues and wasting of muscles (due to starvation, fasting, etc.) Because of slowed metabolism during these conditions FAT loss may actually be at a minimum, less that it would be on a low-calorie diet, when at least SOME food is eaten. Hydrolysis is an example of: a) coupled reaction b) anabolic reaction c) catabolic reaction d) synthesis reaction ------ b) catabolic (breaking) During metabolism, released energy is captured and transferred by: a) enzymes b) pyruvate c) acetal CoA d) adenosine triphosphate ------ d) adenosine triphosphate (ATP) Glycolysis: a) requires oxygen b) generates abundant energy c) converts glucose to pyruvate d) produces ammonia as a by-product ------ c) converts glucose to pyruvate The pathway from pyruvate to acetyl CoA: a) produces lactic acid b) is known as gluconeogenesis c) is metabolically irreversible d) requires more energy that it produces ------ c) is metabolically irreversible For complete oxidation, acetyl CoA enters: a) glycolysis b) the TCA cycle c) the Cori cycle d) the electron transport chain ------ b) the TCA cycle Deamination of an amino acid produces: a) vitamin B and energy b) pyruvate and acetyl CoA c) ammonia and a keto acid d) carbon dioxide and water ------ c) ammonia and a keto acid Before entering the TCA cycle, each of the energy-yielding nutrients is broken down to: a) ammonina b) pyruvate c) electrons d) acetyl CoA ------ d) acetyl CoA The body stores energy for future use in: a) proteins b) acetl CoA c) triglycerides d) ketone bodies ------ c) triglycerides During a fast, when glycogen stores have been depleted, the body begins to synthesize glucose from: a) acetyl CoA b) amino acids c) fatty acids d) ketone bodies ------ b) amino acids metabolism ** ------ all of the chemical reactions which take place in the body energy metabolism ** ------ all of the chemical reactions through which the human body acquires and spends energy from food anabolism ** ------ small compounds joined together to make larger ones; energy must be USED in order to do this catabolism ** ------ larger compounds broken down into smaller ones; energy is RELEASED coupled reaction ** ------ energy released from the breakdown of large compounds used to drive other reactions ATP ** ------ adenosine triphosphate - the body's energy currency; produced when large compounds are broken down; ATP is USED when smaller compounds are made into larger ones ribosomes ** ------ cellular machinery used to make proteins mitochondria ** ------ where energy is derived from fat, CHO, protein via TCA cycle, electron transport chain Breaking down nutrients for energy CHO's Fats Protein What do they break down to and how many carbons do they each have? ------ CHO - glucose (6c) TG's - glycerol (3c) + fatty acid (typically 18c) Protein - amino acids (2C-N, 3C-N, or 5C-N) Breaking down nutrients for energy New compounds; number of carbons ------ Pyruvate (3c) acetyl CoA (2c) Glucose Breakdown CHO (glucose 6c) - pyruvate (3c) With oxygen present..... ------ aerobic glucose (6c) - pyruvate (2c) - Acetyl CoA (2c) - TCA cycle Glucose Breakdown CHO (glucose 6c) - pyruvate (3c) Without oxygen present..... ------ withinadequate oxygen = anaerobic (during strenuous exercize for 1-3 minutes) glucose (6c) - pyruvate (3c) - LACTIC ACID Getting rid of Lactic Acid: Cori Cycle (liver repackages lactic acid as glucose) ------ glucose (6c) - pyruvate (3c) - lactic acid - liver - glucose - back to blood - muscles (stored as glycogen) Fat breakdown: TG's 3 fatty acids + glycerol ------ A) GLYCEROL may be converted to glucose OR pyruvate depending upon cells needs, glucose is made if blood glucose is low -- pyruvate is made if enertgy is needed (will be broken down further in TCA cycle) B) FATTY ACIDS may be converted to acetyl CoA and proceeds through TCA cycle -- requires oxygen to do this; and aerobic process Can you make glucose from fatty acids? ------ NOOOOOO!!!!! Only the glycerol portion of TG's can be coverted to glucose. Protein breakdown: Use of protein depends on cells needs, availability of glucose. Note: Before amino acids can be used, they must be deaminated - take off Nitrogen group 1) If glucose is needed.... 2) If energy is needed and glucose lovel is ade ------ 1) protein - amino acid (deaminated - glucose; glucose used by brain, red blood cells 2) protein - amino acid (deaminated) - glucose - pyruvate -acetal CoA - TCA cycle Note: some amino acids enter pathway and are converted to acetyl CoA, soem amino acids enter the TCA cycle directly 3) amino acid - keto acid (NH3) keto acid - non-essential amino acid (NH3) 4) a method for making non-essential amino acids; B6 needed for this process amino acid A + keto acid B - keto acid A + amino acid B Getting rid of ammonia produced from deamination ------ A) urea cycle (ammonia is toxic; must be converted to nontoxic compound immediately; liver packages ammonia as UREA; kidneys excrete urea B) high protein intake creates more work for the kidneys; if eating a high protein diet increase water intake to keep urea soluble
Side A ------ Side B Metabolism ------ The sum total of all the chemcial reactions that go on in living cells. Energy metabolism includes all the reactions by which the body obtains and spends energy from food. Example: Nutrients provide the body with FUEL and follows them through a series of reactions that release energy from their chemical bonds. As the bonds break, they release energy in a controlled version of the process by which wood burns in a fire. Energy metabolism ------ All of the chemical reactions through which the human body acquires and spends energy from food Anabolism ------ Small compounds joined together to make largers ones; energy must be used in order to do this Ana = up Catabolism ------ Larger compounds BROKEN down into smaller ones; energy is RELEASED kata = down Coupled reactions ------ Energy released from the breakdown of a large compounds is used to drive other reactions ATP ------ Adenosine triphosphate; energy currency of the body -- produced when large compounds are broken down ATP is used to make large compounds from smaller ones. Ribosomes ------ Cellular machinery used to make proteins Mitochondria ------ Where energy is derived from fat, CHO, protein via TCA cycle, electron transport chain Coenzyme ------ Complex organic molecules that work with enzymes to facilitate the enzymes' activity. Many coenzymes have B vitamins as part of their structures. co = with Cofactor ------ The general term for substances that facilitate enzyme action is cofactors; they include both organic coenzymes such as vitamins and inorganic substances such as minerals Enzymes ------ Protein catalysts - proteins that facilitate chemical reactions without being changed in the process Metalloenzyme ------ Enzymes that contain one or more minerals as part of their structure BREAKING DOWN NUTRIENTS FOR ENERGY CHO (Carbohydrate) ------ CHO - glucose (6 carbons) BREAKING DOWN NUTRIENTS FOR ENERGY Fat ------ TG's - glycerol (3 carbons) + fatty acid (typically 18 carbons) BREAKING DOWN NUTRIENTS FOR ENERGY Protein ------ Protein - amino acids 2C-N, 3C-N, or 5C-N BREAKING DOWN NUTRIENTS FOR ENERGY New Compounds ------ Pyruvate (3 carbons) Acetyl CoA (2 carbons) GLUCOSE BREAKDOWN ------ CHO - glucose (6 carbons) - pyruvate (3 carbons) GLUCOSE BREAKDOWN With oxygen present = aerobic ------ Glucose (6C) - pyruvate (3C) - acetyl CoA (2C) - TCA cycle GLUCOSE BREAKDOWN With inadequate oxygen present = anaerobid (during strenous exercise) ------ Glucose (6C) - Pyruvate (3C) - Lactic acid GETTING RID OF LACTIC ACID Cory Cycle (liver repackages lactic acid as glucose) ------ Glucose (6C) - Pyruvate (3C) - Lactic acid - liver - glucose - back to blood - muscles (stored as glycogen) FAT BREAKDOWN Trigycerides ------ TG's - 3 fatty acids + glycerol FAT BREAKDOWN TG's - 3 fatty acids + glycerol Glycerol may be convered to ------ glucose or pyruvate depending on the cells needs; glucose is made if the blood glucose is low; pyruvate is made if energy is needed (will be broken down further in the TCA cycle) FAT BREAKDOWN TG's - 3 fatty acids + glycerol Fatty acids may be converted to ------ acetyl CoA and proceeds through TCA cycle; requires oxygen to do this (an aerobic process) FAT BREAKDOWN TG's - 3 fatty acids + glycerol Can you make glucose from fatty acids? ------ NO!!!!! PROTEIN BREAKDOWN Use of protein depends upon ------ cells needs and availablity of glucose Note: before amino acids maybe used, they must be deaminateed (nitrogen group removed) PROTEIN BREAKDOWN If glucose is needed.... ------ Protein - amino acid (deaminated) - glucose (Glucose is used by the brain, red blood cells) PROTEIN BREAKDOWN If energy is needed and glucose level is adequate.... ------ Protein - amino acid (deaminated) - glucose - pyruvate - aceytl CoA - TCA cycle Note: Some amino acids enter pathway and are converted to acetyl CoA, some amino acids enter the TCA cycle directly. PROTEIN BREAKDOWN Deamination ------ amino acic - keto acid (NH3) keto acid - non-essential amino acid (NH3) PROTEIN BREAKDOWN Transamination ------ A method for making non-essential amino acids; B6 needed for this process amino acid A + keto acid B = keto acid A = amino acid B GETTING RID OF AMMONIA PRODUCED FROM DEAMINATION Urea cycle ------ Ammonia is toxic; must be converted to nontoxic compound immediately; liver packages ammonia as UREA; kidneys excrete UREA High protein intake creates more work for kidneys; if eating high protein diet increase water intake to keep urea soluble ELECTRON TRANSPORT CHAIN (an aerobic process, requires oxygen) Process? ------ 1. Once acetyl CoA (2 carbon) enters the TCA cycle it quickly combines with a 4 carbon compound to create a 6 carbon compound 2. 2 carbons are lost during one turn of the cycle -- they are lost as CO2 3. There are also a number of HYDROGENS that are pulled off compounds and transferred to NAD which carries hydrogens 4. These HIGH ENERGY HYDROGEN atoms (high energy since they desperately want to combine with another molecule/atom so there will be 2 shared electrons) are transferred to NAD (niacin) and FAD (riboflavin) to electron transport chain 5.At the electron transport chain, HIGH ENERGY HYDROGENS (electrons) are take down a series of three little (waterfall) reactions to harness this energy -- ATP's are produced in this series of reactions FEASTING What happens to excess CHO's? ------ 1. CHO's used first to replenish glycogen stores 2. Extra is converted to fat CHO - glucose - pyruvate - acetyl CoA - fatty acids OR CHO - glucose - gylcerol + (see notes) FEASTING What happens to excess Fat? ------ Triglycerides stored directly into fat tissues, no breakdown required (except for chylomicron formation in GI) FEASTING What happens to excess protein? ------ 1. Dispose of Nitrogen group first via deamination 2. keto acid (amino acid minus nitrogen group) may enter metabolic pathway at pyruvate, acetyl CoA stage - acetyl CoA - fatty acids - TG's *Some protein will be used to replenish glycogen stores FASTING What happens if you fast less than 24 hours? ------ Will use up glycogen stores in liver and muscle tissue FASTING What happens if you fast LONGER than 24 hours, but less than 3-4 days? ------ Will begin gluconeogenesis using muscle tissue protein to generate new glucose (about 90% of glucose supplied by breaking down muscle tissue; fat (via glycerol) contributes only 10%) FASTING What happens if you fast LONGER THAN 3-4 DAYS? ------ Body shifts to KETOSIS to preserve muscle tissue; ketone bodies are 2 acetyl CoA' stuck together; some brain tissue is able to use ketone bodies for energy instead of glucose, which helps to preserve muscle tissue FAD DIETS Fad diets which promote eating only protein and fat will result in... ------ KETOSIS after 24 hours of diet ALCOHOL AND NUTRITION Historical findings show humans have used alcohol for over... ------ 5000 years ALCOHOL AND NUTRITION; Biochemisty ethanol ------ alcohol in fermented beverages Fuel ------ Compounds that cells can use for energy. The major fuels include glucose, fatty acids, and amino acids; other fuels include ketone bodies, lactic acid, glycerol and alcohol. Photosynthesis ------ The process by which green plants use the sun's energy to make carbohydrates from carbon dioxide and water. photo = light synthesis = put together (making) Name one of the body's high-energy molecules, and describe how it is used. ------ ATP (adenosine triphosphate) is a common high-energy compound composed of a purine (adenine), a sugar (ribose) and three phosphate groups. During digestion the energy-yielding nutrients - carbohydrates, lipids, and proteins - are broken down to glucose (and other monosaccharides), glycerol, fatty acids, and amino acids. Aided by enzymes and coenzymes, the cells used these products of digestion to build more complex compounds (anabolism) or break them down further to RELEASE ENERGY (Catabolism). THE ENERGY RELEASED DURING CATABOLISM MAY BE CAPTURED BY HIGH ENERGY COMPOUNDS SUCH AS ATP. What are the coenzymes, and what service do they provide in metabolism? ------ MEtabolic reactions almost always require enzymes to facilitate their action. In many cases, the enzymes need assistants to help them. Enzyme helpers are called coenzymes. Coenzymes are complex organic molecules that associate closely with most enzymes, but are not proteins themselves. Without its coenzyme, an enzyme cannot function. Name the four basic units, derived from foods, that are used by the body in metabolic transformations. How many carbons are in the "backbones" of each? ------ Glucose - 6 carbons Glycerol - 3 carbons Fatty acid - even number of carbons (commonly 16 or 18) Amino acid - 2, 3 or more carbons with a Nitrogen attached Define aerobic and nonaerobic metabolism. How does insufficient oxygen influence metabolism? ------ aerobic - requiring oxygen anaerobic - not requiring oxygen an = not Anaerobic pathway yield energy quickly, but cannon be sustaned for long - a couple of minutes at most. You would use this type of pathway during a sprint. Conversely, the aerobic pathways produce energy more slowly, because they can be sustaned for long period of time, their total energy yield is greater. This is the pathway you use most often, even at rest. How does the body dispose of excess nitrogen? ------ The liver continuously produces small amounts of ammonia in deamination reactions (removing nitrogen from amino acids). Some of this ammonia provides the nitrogen needed for the synthesis of nonessential amino acids. The liver quickly combines any remaining ammonia with carbon dioxide to make urea, a much less toxic compound. The liver releases the urea into the bloodstream and it is taken up and excreted by the kidneys. Summarize the main steps in the metabolism of glucose, glycerol, fatty acids and amino acids. ------ The digestion of carbohydrates yields glucose (and other momosaccharides): some is stored as glycogen, and some is broken down to pyruvate and acetal CoA to provide energy. The acetyl CoA can then enter the TCA cycle and electron transport chain to provide more energy. The digestion of fat yields glycerol and fatty acids; some are reassembled nd stored as fat, and others are broken down to acetyl CoA, which can enter the TCA cycle and electron transport chain to provide energy. The digestion of protein yields amino acids, most of which are used to build body protein or other nitrogen-containing compounds, but some amino acids may be broken down through the same pathways as glucose to provide energy. Other amino acids enter directly into the TCA cycle, and these, too, can be broken down to yield energy. In summary, although carbohydrate, fats and protein enter the TCA cycle by different routes, the final pathways are common to all energy-yielding nutrients. Describe how a surplus of the three energy nutrients contributes to body fat stores. ------ ALL EXCESS NUTRIENTS STORED AS FAT!!! Carbohydrate - broken down to glucose - used for liver and muscle glycogen stores - excess stored as FAT Fat - broken down to fatty acids - stored directly as FAT Protein - broken down to amino acids - used for body proteins - some loss of nitrogen in urine (urea) and then excess stored as FAT What adaptations does the body make during a fast? ------ *Increasing the breakdown of fat to provide energy for most of the cells *Using glycerol and amino acids to make glucose for the red blood cells and central nervous system *Producing keytones to fuel the brain *Supressing appetite and slowing metabolism. All these measures conserve energy and minimize loses. What are ketone bodies? ------ Ketone bodies are compounds produced during the imcomplete breakdown of fat when glucose is not available. Ketosis is a sign that the body's chemisty is going awry; Ketosis is the body's way to use its fats stores to fuel the brain by using ketones as an alternature fuel source. The brain prefers glucose. Define ketosis ------ An undesirably high concentration of ketone bodies in the blood and urine. Ketosis is the body's way to use its fats stores to fuel the brain by using ketones as an alternature fuel source, when glucose is limited (during starvation). Distinguish between a loss of fat and a loss of weight, and describe how each might happen. ------ Weight loss can be caused by shrinkage in the mass of organ tissues and wasting of muscles (due to starvation, fasting, etc.) Because of slowed metabolism during these conditions FAT loss may actually be at a minimum, less that it would be on a low-calorie diet, when at least SOME food is eaten. Hydrolysis is an example of: a) coupled reaction b) anabolic reaction c) catabolic reaction d) synthesis reaction ------ b) catabolic (breaking) During metabolism, released energy is captured and transferred by: a) enzymes b) pyruvate c) acetal CoA d) adenosine triphosphate ------ d) adenosine triphosphate (ATP) Glycolysis: a) requires oxygen b) generates abundant energy c) converts glucose to pyruvate d) produces ammonia as a by-product ------ c) converts glucose to pyruvate The pathway from pyruvate to acetyl CoA: a) produces lactic acid b) is known as gluconeogenesis c) is metabolically irreversible d) requires more energy that it produces ------ c) is metabolically irreversible For complete oxidation, acetyl CoA enters: a) glycolysis b) the TCA cycle c) the Cori cycle d) the electron transport chain ------ b) the TCA cycle Deamination of an amino acid produces: a) vitamin B and energy b) pyruvate and acetyl CoA c) ammonia and a keto acid d) carbon dioxide and water ------ c) ammonia and a keto acid Before entering the TCA cycle, each of the energy-yielding nutrients is broken down to: a) ammonina b) pyruvate c) electrons d) acetyl CoA ------ d) acetyl CoA The body stores energy for future use in: a) proteins b) acetl CoA c) triglycerides d) ketone bodies ------ c) triglycerides During a fast, when glycogen stores have been depleted, the body begins to synthesize glucose from: a) acetyl CoA b) amino acids c) fatty acids d) ketone bodies ------ b) amino acids metabolism ** ------ all of the chemical reactions which take place in the body energy metabolism ** ------ all of the chemical reactions through which the human body acquires and spends energy from food anabolism ** ------ small compounds joined together to make larger ones; energy must be USED in order to do this catabolism ** ------ larger compounds broken down into smaller ones; energy is RELEASED coupled reaction ** ------ energy released from the breakdown of large compounds used to drive other reactions ATP ** ------ adenosine triphosphate - the body's energy currency; produced when large compounds are broken down; ATP is USED when smaller compounds are made into larger ones ribosomes ** ------ cellular machinery used to make proteins mitochondria ** ------ where energy is derived from fat, CHO, protein via TCA cycle, electron transport chain Breaking down nutrients for energy CHO's Fats Protein What do they break down to and how many carbons do they each have? ------ CHO - glucose (6c) TG's - glycerol (3c) + fatty acid (typically 18c) Protein - amino acids (2C-N, 3C-N, or 5C-N) Breaking down nutrients for energy New compounds; number of carbons ------ Pyruvate (3c) acetyl CoA (2c) Glucose Breakdown CHO (glucose 6c) - pyruvate (3c) With oxygen present..... ------ aerobic glucose (6c) - pyruvate (2c) - Acetyl CoA (2c) - TCA cycle Glucose Breakdown CHO (glucose 6c) - pyruvate (3c) Without oxygen present..... ------ withinadequate oxygen = anaerobic (during strenuous exercize for 1-3 minutes) glucose (6c) - pyruvate (3c) - LACTIC ACID Getting rid of Lactic Acid: Cori Cycle (liver repackages lactic acid as glucose) ------ glucose (6c) - pyruvate (3c) - lactic acid - liver - glucose - back to blood - muscles (stored as glycogen) Fat breakdown: TG's 3 fatty acids + glycerol ------ A) GLYCEROL may be converted to glucose OR pyruvate depending upon cells needs, glucose is made if blood glucose is low -- pyruvate is made if enertgy is needed (will be broken down further in TCA cycle) B) FATTY ACIDS may be converted to acetyl CoA and proceeds through TCA cycle -- requires oxygen to do this; and aerobic process Can you make glucose from fatty acids? ------ NOOOOOO!!!!! Only the glycerol portion of TG's can be coverted to glucose. Protein breakdown: Use of protein depends on cells needs, availability of glucose. Note: Before amino acids can be used, they must be deaminated - take off Nitrogen group 1) If glucose is needed.... 2) If energy is needed and glucose lovel is ade ------ 1) protein - amino acid (deaminated - glucose; glucose used by brain, red blood cells 2) protein - amino acid (deaminated) - glucose - pyruvate -acetal CoA - TCA cycle Note: some amino acids enter pathway and are converted to acetyl CoA, soem amino acids enter the TCA cycle directly 3) amino acid - keto acid (NH3) keto acid - non-essential amino acid (NH3) 4) a method for making non-essential amino acids; B6 needed for this process amino acid A + keto acid B - keto acid A + amino acid B Getting rid of ammonia produced from deamination ------ A) urea cycle (ammonia is toxic; must be converted to nontoxic compound immediately; liver packages ammonia as UREA; kidneys excrete urea B) high protein intake creates more work for the kidneys; if eating a high protein diet increase water intake to keep urea soluble
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