* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Untitled
Gene regulatory network wikipedia , lookup
Photosynthesis wikipedia , lookup
Pharmacometabolomics wikipedia , lookup
Paracrine signalling wikipedia , lookup
Proteolysis wikipedia , lookup
Biosynthesis wikipedia , lookup
Amino acid synthesis wikipedia , lookup
Light-dependent reactions wikipedia , lookup
Photosynthetic reaction centre wikipedia , lookup
Microbial metabolism wikipedia , lookup
Biochemical cascade wikipedia , lookup
Glyceroneogenesis wikipedia , lookup
Fatty acid metabolism wikipedia , lookup
Oxidative phosphorylation wikipedia , lookup
Citric acid cycle wikipedia , lookup
Metabolic network modelling wikipedia , lookup
Evolution of metal ions in biological systems wikipedia , lookup
Adenosine triphosphate wikipedia , lookup
Biochemistry wikipedia , lookup
Metabolic Fuel There are 2 main protein sites within the body, one of these is extracellular (collagen) located particularly in the bone matrix & skin & this does not appear to be readily available as a source of fuel, the other is intracellular (striated muscle) which in human is the main source of protein used as fuel. The amount of adipose tissue varies considerably & in obese person may be between 50-100 kg above normal. The significance of the difference between muscle & adipose tissue as potential energy sources is that muscle protein is associated with about 3 times its own weight of water & provides 4 kcal/g. Where as adipose tissue fat is usually anhydrous & provides 9 kcal/g, thus 100g of skeletal muscle will yield about 100kcal where as 100g of adipose tissue yield 900 kcal. Apart from fat, the only other significant body stores of fuel which can be used over a long period is protein particularly that of skeletal muscle. There are also a number of short-term body stores of fuel; these include glycogen, the circulating body pool of free glucose, triacylglycerol, free fatty acids & amino acids. The main metabolic fuels circulates in the plasma as their constituent; protein in the form of amino acids particularly Alanine & Glutamine from skeletal muscles, CHO predominantly as glucose but also in exercise as lactate & pyruvate, & fat as triacylglycerol (chylomicron & VLDL), non-esterified fatty acids & glycerol. Metabolism Network of chemical processes involved in maintaining life & include all of the sequence of chemical reactions that occurs in the body, the chemical reactions enable cells to release & use energy from food,, convert one substance in to another & prepare waste products for excretion. Pathway; a progression of metabolic reaction from the beginning to the end. Intermediate : these are compounds produced as pathway proceed. Anabolic pathway; Build new compounds, energy must be expended for anabolic process to take place. Building block; Chemical elements & compounds used to form new substances. Catabolic pathway; Breakdown compounds in to small units, energy is released in the process, some is trapped for cell use & the rest is lost as heat. The production of energy for cell use occurs in 3 sages: First stage: large food molecules such as protein, starch & triglyceride are broken down during digestion & absorption in to smaller units such as amino acids, monosacharides (simple sugars) & fatty acids. Second stage: most of these smaller compounds are further degraded to the 2-carbon intermediate compound acetic acid. Third stage: acetic acid is degraded to carbon dioxide & water, the electron & hydrogen ions released during this metabolic process are donated to O2 atoms to form water, some of this energy released in this catabolic process drives the synthesis of ATP which is the form of energy used by the cell. The form of energy that the cell use for chemical, electrical & osmotic processes is ATP, to release energy in ATP, cell split it in to Adenosine Diphosphate (ADP) plus Pi, a free (inorganic phosphate group), ADP can also split to Adenosine Monophosphate (AMP) plus Pi to yield energy. Muscles are capable of performing a reaction during intense exercise when ATP is in short supply (ADP+ADP= ATP+AMP). Only energy in ATP & its derivatives can be used directly by the cells, energy released by breaking carbon-hydrogen bonds in glucose molecules is one of the fuels used by the body cells to make ATP. Metabolic pathways exist in every cell that can combine ADP & Pi to form ATP, an enzyme later can break the ATP bond to release energy needed for metabolic reactions. During metabolism a cell is constantly breaking down ATP in one organelle while rebuilding it in another, an exhausted muscle cell has a very high concentration of ADP & a very low concentration of ATP, when this happens, muscle cell activity such as muscle contraction may slow down or stop. A low ATP concentration then stimulate metabolic processes that produce ATP & only by resynthesizing needed ATP can the muscle cell ready itself for future action. The synthesis of ATP from ADP & Pi involves the transfer of energy from food, this uses oxidationreduction reactions, where electrons along with hydrogen ion are transferred from CHO, protein & fat eventually to O2, this reaction forms water & releases much energy which can be used to produce ATP. Regulation of Metabolism Factors which regulate metabolism: 1. Enzymes : they are the key regulators for metabolic pathways, both their presence & their rate of activity are important to chemical reactions in the body. 2. Hormones : includes insulin, glucagons & epinephrine also serves as regulators of metabolic processes. 3. ATP concentration in a cell : also regulate metabolism, high ATP concentration decrease energy yielding reactions such as glycolysis & promote synthetic reactions such as lipogenesis which uses ATP, while high ADP concentration stimulate energy-yielding pathway. 4. Liver : which contains a variety of enzymes & most nutrient pass through it, providing an opportunity for metabolic control. 5. Many vitamins & minerals : participate in regulating metabolism like B-vitamins, iron cupper & Mg.