Analysis of Metabolic Strategies Essay

There are many micronutrients (substances needed in small amounts) essential to healthy living. These micronutrients include the vitamins, minerals and amino acids. A healthy diet includes the proper ratio of macronutrients along with the essential quantities of micronutrients. What is their biochemical or metabolic function? Subdivision of the global network was often based on the biochemical function of the pathway (i. e. amino acid metabolism, nucleotide metabolism). As an example of a biochemical pathway, note the first four reactions of glycolysis as follows: (1) glucose + ATP –(hexokinase)? glucose-6-phosphate + ADP; (2) glucose-6-phosphate ? (phosphoglucose isomerase)? fructose 6-phosphate; (3) fructose 6-phosphate + ATP –(phosphofructose kinase)? Fructose 1,6-diphosphate + ADP; (4) fructose 1,6-diphosphate -(aldolase)? dihydroxyacetone phosphate + glyceraldehyde 3-phosphate Metabolism to generate energy for biochemical functions is carried out by all cells. Some tissues, because of their specialized functions in the multi-cellular organism, have different metabolic strategies. Muscle and liver have particular roles in overall metabolism: the brain has specific needs. Describe, compare and contrast the metabolic strategies during periods of high metabolic activity of muscle, liver, brain, and the general body tissues and in the ‘fed’ (digesting a meal) and ‘unfed’ (no nutrients coming from digestive tact) states. Having highly directional reactions at start and finish of a pathway is good metabolic strategy. The hexokinase and phosphofructokinase steps drive substrates into the sequence; the pathway can continue even if substrates are significantly depleted. Pyruvate kinase clears intermediates out of the pathway. Vitamins, minerals and amino acids are essential organic nutrients, essential molecular structures for life processes, that we cannot synthesize and must take in, in adequate amounts, as food. The following are the biological and metabolic functions of vitamins. Water soluble vitamin such as Vitamin C or ascorbic acid, which can be found in papaya, oranges, orange juice, kiwifruit, strawberries, cantaloupe, sweet red peppers, cauliflower, broccoli, brussels, sprouts, green peppers, grapefruit, kale, and strawberries, is important in the synthesis of collagen, which is the main structural component of the skin as well as many other body tissues. Vitamin C also works as a powerful antioxidant, aids in the absorption of iron, is critical in fighting off infections, helps alleviate allergic reactions, and aids in wound healing. Another water soluble vitamin, Thiamin or Vitamin B1 can be found in lean pork, sunflower seeds, wheat germ, whole or enriched grain products, organ meats and nuts and legumes. It is the required coenzyme or helper molecule in the metabolism of carbohydrates for energy, and proper transmission of nerve signals. It is also necessary for normal muscle function, growth, digestion, DNA replication, and normal appetite. Riboflavin or Vitamin B2, which can be found in milk, yogurt, cocoa, cheeses, eggs, meat and green leafy vegetables, is necessary in the release of energy from carbohydrates, the activation of many vitamins, and the breakdown of fat. Also required for the normal growth and tissue repair are the synthesis of red blood cells, corticosteroids, and glycogen. Niacin or Vitamin B3, which can be found in tuna, halibut, beef, chicken, turkey, pork, cereal grains, fortified cereals, seeds, legumes, peanut butter, is required by all cells and vital in the release of energy from food. It is also required for the synthesis of protein, fat, and genetic material. It is also required for proper metabolism and brain function. Panthothenic acid or Vitamin B5, which is widely distributed in foods, can be found in liver, peanuts, wheat germ, brewer’s yeast, egg yolk, legumes, whole grain cereals, mushrooms, broccoli, avocados, royal jelly from bees. It is critical in the synthesis and breakdown of many body compounds. It is necessary for the metabolism of food and normal immune function. Also plays a role in the synthesis of hormones, cholesterol, and neurotransmitters. Biotin is widely distributed and can be found in liver, soybeans, egg yolk, cereal, yeast, legumes, nuts. It is needed for proper energy metabolism (especially carbohydrates and protein) and growth. It is critical in the production of fatty acids, prostaglandins, antibodies, digestive enzymes, hormones, and cholesterol. It is also important in niacin metabolism. Folic acid is a synthetic form found in fortified cereals and supplements. It is also called Folate (natural form found in food). It can be found in brewer’s yeast, beans, spinach, wheat germ, asparagus, turnip greens, green leafy vegetables, fortified cereals. It is important in the metabolism of proteins and in the synthesis of new proteins. It is a necessary component in the production of red blood cells, necessary for normal cellular division and production of DNA. Folate also increases appetite and digestive acids. Research is also showing folate may reduce the risk for heart disease and certain cancers. Folate plays an important role in tissue growth and function and can significantly reduce the risk of neural tube defects (birth defects of the brain or spine). Vitamin B12 or cobalamin, which can be found in meat and meat products, poultry, fish, yogurt, fortified cereals, fortified soy-milk, tuna, shellfish, eggs and fortified tofu, is important in metabolism, essential for DNA synthesis, production of red blood cells, and proper nerve function. Inadequate absorption of the vitamin rather than inadequate dietary intake is responsible for more than 95% of the vitamin B12 deficiency seen in the US. A strict vegetarian diet can produce a deficiency, although clinical symptoms may not appear for up to 20-30 years. Vitamin B6 or pyridoxine, which can be found in potato, bananas, beans, walnuts, watermelon, meats, salmon and light meat of chicken, is needed for proper protein metabolism, the conversion of tryptophan to niacin, and the synthesis of fatty acids. It is Necessary for normal growth, proper brain and immune function, synthesis of red blood cells, and hormone regulation. Fat soluble vitamin like vitamin A or retinol (comes from animal sources like egg yolks, butter, whole milk products, liver and fish liver oils) or beta-carotene (precursor to Vitamin A, which comes from plant sources like pumpkin, spinach (boiled), butternut squash cantaloupe and dark leafy greens). It is a powerful antioxidant which helps the body fight free-radical damage and seems to provide some protection against cancer. It is essential for normal vision, reproduction, growth, immune function, healthy skin and mucous membranes, and normal bone growth and development. Vitamin D comes primarily in foods of animal origin like eggs, liver, butter, fatty fish, salmon with bones, fortified soy milk and fortified foods such as milk and margarine. Vitamin D can also be made by the body when the skin is exposed to sunlight. It is essential to maintain bone and teeth strength and integrity. It also aids in calcium absorption. Vitamin E comes from pant oils (such as sunflower and safflower oil), wheat germ, whole grains, unroasted almonds, sunflower seeds, Brazil nuts, mango, green leafy vegetables and broccoli. Vitamin E is well on its way to becoming a superhero in the antioxidant army. Due to its fat-soluble nature it can do its antioxidant work where most of the other antioxidants can’t go. Vitamin E is incorporated into cell membranes as well as guarding the the fat molecules in the bloodstream from free-radical damage. Studies have also shown that it is a potent stimulator of the immune system, helping protect the thymus gland and guarding white blood cells from damage. Vitamin E has also been shown to reduce levels of inflammatory prostaglandins, which can lead to a number of health problems. By keeping the body’s level of Vitamin E from dropping you will benefit from a decreased incidence of various cancers, decreased risk of heart disease and strokes, and free-radical protection. When incorporating exercise and physical activity into your daily life Vitamin E becomes even more important. As you exercise, your rate of respiration increases which leads to an increase in the production of free-radicals. This increase in free-radical production has been shown to play an important role in causing skeletal muscle damage and inflammation after strenuous exercise. Vitamin K, which comes primarily from plant foods, spinach, broccoli, kale, Brussels, sprouts, cabbage, lettuce, cereals, fruits, dairy products and meats. Bacteria in the gastrointestinal tract also provide a the body with vitamin K. It is essential for proper blood clotting and plays a role in normal bone calcification. For the minerals like calcium, sources are milk, milk products, calcium fortified, orange juice, part-skim ricotta cheese, yogurt, cocoa, sardines, clams, oysters, turnip greens, mustard greens, broccoli, legumes and dried fruit. It is essential for normal bone and tooth formation, overall growth, blood clotting, regulation of heart rate, and proper nerve transmission. Phosphorus may come from meat, poultry, fish, eggs, milk, milk products, nuts, legumes, cereals, grains, chocolate, lettuce and tomato. It is essential for a number of biochemical reactions in the body, especially energy production, metabolism of protein, carbohydrate and fat, and building protein. It also gives strength to bones and teeth, and plays a role in the regulation of acid-base balance, muscle contraction, kidney function, and proper nerve function. Magnesium, which comes from nuts and seeds, legumes, green vegetables, tofu, wheat germ, cereal grains, soybeans, chocolate, blackstrap molasses, corn, peas, carrots, seafood, brown rice, parsley, lima beans and spinach. It is essential in hundreds of biochemical reactions and a wide range of metabolic activities including the use of energy and the metabolism of carbohydrates, lipids, proteins, and genetic material. It is also necessary for proper nerve transmission, contraction of muscle, and the conversion of Vitamin D to its active form. Spinach is essential in hundreds of biochemical reactions and a wide range of metabolic activities including the use of energy and the metabolism of carbohydrates, lipids, proteins, and genetic material. It is also necessary for proper nerve transmission, contraction of muscle, and the conversion of Vitamin D to its active form. Sodium, which can be found in table salt, cured meat, cheese and bread, is necessary for the regulation of water balance within the body, the passage of substances in and out of each cell, and the maintenance of a normal body pH. Also plays a role in the generation of normal electrical nerve signals, muscle contraction, and the regulation of blood pressure. Potassium is an essential part of every cell in the body and required for normal growth. It is also involved in the release of energy from food, the synthesis of protein, regulation of water balance in the body, proper nerve and muscle function, and regulation of blood pressure. Chloride can be found in table salt, seafood, tomatoes, rye and olives. It helps maintain water balance and acid-base balance in the body. Iron, which can be found in meat (provides iron in the non-heme form which is the easiest for the body to absorb), blackstrap molasses, clams, oysters, tofu, legumes, nuts and seeds, red meats, dark green leafy vegetables (Vegetables provide iron in the non-heme form, which is harder for the body to absorb. Consuming vitamin C with iron rich foods will help increase absorption), soybeans, pumpkin seeds, dried fruits, enriched and/or whole-grain, breads and cereals, is critical in making new red blood cells, immune defense cells, white blood cells, and normal brain function. Zinc, which can be found in oysters, wheat germ, beef, liver, dark meat of turkey and, chicken, peanuts, whole grains, miso, legumes, sunflower seeds, blackstrap molasses, green peas, spinach, broccoli. It is essential for proper growth of skin, hair, and nails, healing wounds, and a healthy immune system. It is necessary in many chemical reactions and for a normal sense of taste and smell. It also functions as a detoxifier of the body and plays a role in the metabolism of carbohydrates. Copper, which can be found in liver, shellfish, whole grains, mushrooms, cherries, legumes, cocoa, nuts, eggs, muscle meats, fish and poultry, is a critical component of the outer coating of nerve fibers, collagen, and used in the production of skin pigments. Also works with iron to make healthy red blood cells. Seleniem, which can be found in grains, seeds, potatoes, meat, poultry, fish, garlic, brewer’s yeast and wheat germ, is important antioxidant that works with vitamin E to protect the body from free-radical damage. It is also associated with fat metabolism, a healthy immune system, and important to male fertility. Chromium, which can be found in wheat germ, brewer’s yeast, peas , chicken, corn oil mushrooms, prunes, nuts, asparagus, organ meats and whole-grain bread and cereals, is necessary for blood sugar regulation and metabolism of fats and carbohydrates. Iodine, which comes from iodized salt, saltwater seafood, sunflower seeds, mushrooms, eggs, beef liver, peanuts, spinach, pumpkin, broccoli, chocolate and kelp, is needed for proper thyroid gland operation and normal metabolism of cells. Manganese which comes from wheat bran, legumes, nuts, lettuce, leafy green vegetables, blueberries, pineapple, seafood, poultry, meat and tea, is needed for normal utilization of several other vitamins, and a variety of other biochemical roles in the body. It also aids in proper fat metabolism, skeletal and connective tissues, production of energy, making cholesterol and DNA, proper brain function, and processing blood sugar. Molybdenum, which can be found in milk and milk products, soybeans, lentils, pasta, buckwheat, oats, rice, wheat germ and sunflower seeds, is important in many biochemical reactions, aids in the metabolism of iron, helps prevent gout by removing uric acid from the body, and helps the body burn fat. It is also part of healthy bones, teeth, kidney, and liver, and helps the body use its iron reserves. and helps the body use its iron reserves. Flouride, which comes from mackerel, sardines, salt pork, salmon, shrimp, meat, sunflower seeds, kale, potatoes, watercress, honey, wheat and tea, reduces dental caries and may minimize bone loss by helping the body retain calcium. Nickel, which can be found in nuts, legumes, shellfish, cocoa products, green beans, spinach, rice and tea, is important in many biochemical reactions, and thought to play a role in the metabolism of fats and blood sugar regulation. Silicon, which can be found in whole grains, root vegetables and unrefined cereal products, is needed for healthy body tissues. Vanadium can be found in shellfish, spinach, parsley, mushrooms, whole grains, dill seeds, black pepper, parsley, soy, corn and olives. Research has not documented exactly what vanadium does for the body. It is likely that it plays a role in energy production, biochemical reactions, blood sugar and fat metabolism, and bone and teeth strength. Most foods contain less than 0. 3ug/g arsenic. Seafood is the richest source of arsenic. Arsenic has precise function in the body is still unknown, but it is likely that it plays a role in the metabolism of phospholipids. Boron, which can be found in fruits, vegetables, legumes and nuts is required for normal bone integrity. Amino acids are the principal building blocks of proteins and enzymes. They are incorporated into proteins by transfer RNA according to the genetic code while messenger RNA is being decoded by ribosomes. During and after the final assembly of a protein, the amino acid content dictates the spatial and biochemical properties of the protein or enzyme. The amino acid backbone determines the primary sequence of a protein, but it is the nature of the side chains that determine the protein’s properties. Amino acid side chains can be polar, non-polar, or practically neutral. Polar side chains tend to be present on the surface of a protein where they can interact with the aqueous environment found in cells. On the other hand, non-polar amino acids tend to reside within the center of the protein where they can interact with similar non-polar neighbors. This can create a hydrophobic region within an enzyme where chemical reactions can be conducted in a non-polar atmosphere. Likewise, enzymes can also have polar amino acid substituents within the active site that provide a polar region in which to conduct biochemical synthesis. In addition to their role in protein and enzyme synthesis, amino acids are actively involved in a broad range of functions in the body. For instance, the organic substances help form cells, heal damaged tissues, and produce antibodies. These antibodies are important to the body’s efforts to ward off potentially harmful invasions of viruses and bacteria (Weigel and Seitz, 2006). Also active as metabolic intermediates, amino acids are capable of transporting oxygen through the body and play a part in muscular function. Several of the amino acids, such as the neurotransmitter gamma-aminobutyric acid (GABA) that is found in the central nervous system, but not in proteins, carry out very specific roles in the body. Other examples of such amino acids include carnitine, which is concerned in fatty acid transport within a cell, as well as ornithine and citrulline, both of which are key components in the body’s urea cycle. Essential amino acids are generally contained in the greatest quantities in meat, poultry, fish, eggs, and other animal products. They are also, found, however in grains, legumes, and similar vegetable sources of protein, though one or more essential amino acids may be missing from such foods. For this reason, vegetarians are generally urged to carefully consume a wide range of foods in order that they regularly obtain the complete array of essential amino acids, since different plants lack different types of the important compounds. Nevertheless, amino acid deficiencies are extremely rare in the United States, since Americans commonly consume twice as much protein as is considered necessary each day. Moreover, for athletes or other individuals who need greater amounts of amino acids than most people, supplements are widely available. Some amino acids are even prescribed as a form of medical treatment. Lysine, for example, is utilized to suppress the herpes virus and phenylalanine gains use in some pain and depression therapies. Nevertheless, over-consumption of amino acids can be hazardous, since the compounds can be toxic in excessive quantities. Eukaryotes, such as ourselves, are characterized by membrane bound internal compartments or organelles (Mergaert, et al. , 2006). These compartments allow cells to (a) conserve resources by producing proteins at the appropriate concentration only in these organelles, (b) separate functional areas that might interfere with each other, e. g. , lysosomes, ER and nucleus, and (c) manage reactions in biochemical pathways. Aspects of the carbohydrate, amino acid and fatty acid metabolic processes we have considered have steps that occur in the cytoplasm and the mitochondrion or other cellular organelles (Embley and Martin, 2006). In here, a multi-step reaction within a cell is catalyzed by enzymes. Almost every reaction that occurs within an organism (which is to that organism’s benefit) occurs along a biochemical pathway and is catalyzed one or a series of enzymes. Biochemical pathways are discussed fully by Stryer (1987) â€Å"Biochemical pathways are the organizational units of metabolism, the pathways that energy and materials follow in the cell. † A biochemical pathway may be anabolic, catabolic, or both. An anabolic biochemical pathway may be referred to as a biosynthetic pathway. An example of a catabolic bioochemical pathway is transduction of the chemical energy found in foods into a usable form (digestion, glycolysis, cellular respiration). The biochemical pathways are glycolysis, citric acid cycle, electron transport system, lipid metabolism and amino acid metabolism. These different parts of the processes is performed in different cellular compartments. Citric Acid Cycle occurs in the matrix of the mitochondria. All the reactions of the citric acid cycle take place in the mitochondrial matrix with the exception of succinic dehydrogenase, which is part of Complex II of the inner membrane. It is important not to regard FADH2 as the product of this reaction, which is still often done. FAD is the first, but only a transient, carrier of electrons from succinate to ubiquinone. Indeed the official name of the enzyme is succinate dehydrogenase (ubiquinone). The mitochondrion is often regarded as the powerhouse of the cell, and this designation becomes much more meaningful if we remember that a flow of electrons is an electric current, and NADH and succinate provide the fuel for an electricity generator. The pathway is often called the electron transport chain, but its function is to create a flow of electrons (shown in Fig. 1 as heavy red arrows) to provide the energy needed to translocate protons from the mitochondrial matrix to the inter-membrane space (Nicholson, 2002). The Electron Transport System occurs in the inner membrane of the mitochondria. Mitochondria function during aerobic respiration to produce ATP through oxidative phosphorylation. The respiratory enzymes and electron carriers for the electron transport system are located within the inner mitochondria membrane. The enzymes for the citric acid cycle (Krebs cycle) are located in the matrix. Glycolysis occurs in the cytosol of the cytoplasm. In eukaryotes, glycolysis takes place within the cytosol of the cell. Some of the glycolytic reactions are conserved in the Calvin cycle that functions inside the chloroplast. This is consistent with the fact that glycolysis is highly conserved in evolution, being common to nearly all living organisms. This suggests great antiquity; it may have originated with the first prokaryotes, 3. 5 billion years ago or more. Metabolism to generate energy for biochemical functions is carried out by all cells. Some tissues, because of their specialized functions in the multi-cellular organism, have different metabolic strategies. Muscle and liver have particular roles in overall metabolism: the brain has specific needs. Describe, compare and contrast the metabolic strategies during periods of high metabolic activity of muscle, liver, brain, and the general body tissues and in the ‘fed’ (digesting a meal) and ‘unfed’ (no nutrients coming from digestive tact) states. Absorptive state is the period during which ingested nutrients enter blood and some of these nutrients supply the energy need of the body while the remainder is stored. Post-absorptive state is the period during which the GI tract is empty of nutrients and body stores must supply required energy. In the absorptive state, carbohydrates and proteins are absorbed primarily as monosaccharides and amino acids, respectively, into the blood while fat is absorbed as triacylglycerols into the lymph. During this state, glucose is the major energy source and some of it is converted to glycogen and stored in skeletal muscle and liver. In adipose tissue, glucose is transformed and stored as fat. Fatty acids of plasma chylomicrons are released within adipose tissue capillaries and form triacylglycerols. Most amino acids enter cells and are used to synthesize proteins and any excess amino acids are converted to carbohydrate or fat. On the other hand, in the postabsorptive state, the net synthesis of glycogen, fat, and protein ceases, and net catabolism of these substances begins. Plasma glucose level is maintained by Glycogenolysis, which is the hydrolysis of glycogen stores in liver, adipose tissues, brain, muscles, skeletal muscles, etc. ; Lipolysis, catabolism of triacylglycerols into glycerol and fatty acids in adipose tissues wherein any glycerol reaching the liver is converted to glucose; and protein is catabolized to glucose. References: Embley, T. M. , & Martin, W. (2006). Eukaryotic evolution, changes and challenges. Nature, 440(7084), 623-630. Mergaert, P. , Uchiumi, T. , Alunni, B. , Evanno, G. , Cheron, A. , Catrice, O. , et al. (2006). Eukaryotic control on bacterial cell cycle and differentiation in the Rhizobium-legume symbiosis. Proc Natl Acad Sci U S A, 103(13), 5230-5235. Nicholson, D. 2002. Biochemistry and Molecular Biology Education Vol. 30, No. 1, pp. 3-5. The International Union of Biochemistry and Molecular Biology. Stryer, Lubert (1987). Biochemistry. W. H. Freeman. Weigel, C. , & Seitz, H. (2006). Bacteriophage replication modules. 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