Explore and explain the main features involved in the anabolic metabolism of carbohydrate (glycogenisis), lipid metabolism (triglyceride storage, transport and ketosis) and protein metabolism (transamination and deamination).
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Biochemistry Assignment 7 Task 5) - Explore and explain the main features involved in the anabolic metabolism of carbohydrate (glycogenisis), lipid metabolism (triglyceride storage, transport and ketosis) and protein metabolism (transamination and deamination). Anabolic metabolism is the building of larger molecules from smaller ones, for example building monosaccharides to form carbohydrates; fatty acids and glycerol to form lipids and amino acids to form proteins. They are generally condensation reactions, producing water as two molecules join together to make a larger molecule. All living cells must metabolise to produce vital energy that is required for active processes, this requires glucose. The normal glucose level is 90mg of glucose in 100cm3 of blood it is essential that this level remains and the body controls this in two ways, the breakdown of products to form glucose and synthesis of larger molecules from glucose in order that it be stored. Glycogenisis is the conversion of glucose into glycogen which can then be stored in the liver and muscles. When there is an excess of glucose in the body, the pancreas produces insulin, which converts glucose to glucose - 6 - phosphate and ultimately to glycogen. Carbohydrates are made up of many single sugars (monosaccharides)
This is one triglyceride; many animals store triglycerides as energy, because gram for gram they yield more than twice as much energy as proteins or carbohydrates. Due to the large amounts of C - H bonds, they can break down in respiration to form energy. Lipids are not as large as polysaccharides, proteins and nucleic acids, and so when they need to be transported around the body they can easily diffuse through the barriers, they need to move with the concentration gradient, from an area of high concentration to an area of relative lower concentration. When lipids first enter the body through food they must move through the digestive system, they are broken down and converted to micelles (microscopic droplets) these dissolve in water and pass through into the epithelial cells of the small intestine. Once inside the cells the fatty acids and glycerol can regroup and form triglycerides, but added to this is a protein coat which stops them sticking together, they are now ready to leave the cell in the form of chylomicrons. These molecules do not go into the blood stream, but into the lacteal, a branch of the lymphatic system. The chylomicrons remain suspended in the lymph fluid giving it a milky white colour until they move into a larger lymphatic vessel and eventually drained into a large duct, which empties into the blood.
Deamination is the catabolic metabolism process, which breaks down the amino acids by removing the amino group (NH2) converting the amino acid to ammonia (NH3). The resulting products are: - an organic acid, which is respired, and ammonia, which is toxic to the body. The ammonia is quickly further broken down to form a less harmful product, urea in the ornithine cycle, shown below, and is removed by the kidneys. Transamination is the metabolic process of synthesising amino acids by converting other substances. There are 20 amino acids that we use in the body, eight of these are essential and must be eaten in the diet, as they cannot be synthesised by the human body. The other twelve amino acids are classed as 'non-essential', as they can be synthesised by the metabolic process transamination, which takes place in the liver. An amino group is removed from an amino acid and transferred to an acid, making a new amino acid. This shows that both metabolic reactions are important, if there are too many amino acids in the body, they must be broken down by deamination, if there are not enough of the 'non-essential' amino acids they must be synthesised by transamination. All metabolic reactions are important in the body, they produce things that we need and remove the substances that are no longer required, and this helps to keep the body functioning properly.
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