TASK 8 SELF- REFLECTION ON CARBOHYDRATES

In studying the topic of carbohydrates which taught by Dr. Mickey Vincent, I can describe the various types of carbohydrates and its function in our daily life. Carbohydrates is the most abundant biological molecules on Earth. Carbohydrates is produced through CO2 fixation during photosynthesis. Carbohydrates characterized as organic compounds with the empirical formula Cn(H2O)n which consists of carbon, hydrogen, and oxygen, with hydrogen : oxygen atom ratio of 2 : 1 (as in water). There are three classes of carbohydrates which are monosaccharides, disaccharides, and polysaccharides.

           First class is monosaccharides which is simply sugars are formed by only one polyhydroxy aldehydeidic or ketonic unit. Monosaccharides are classified according to the number of carbon such triose (C3H6O3), tetrose (C4H8O8), pentose (C5H10O5), hexose (C6H12O6), heptose (C7H14O7) and octose (C8H16O8). The common monosaccharides are glucose, fructose, and galactose. Each simple sugar has a cyclic structure and is composed of carbon, hydrogen and oxygen in ratios of 1:2:1 respectively. The most abundant monosaccharide is D-glucose, also called dextrose. Glucose in the blood is taken up into our body's cells and used to produce a fuel molecule called adenosine triphosphate (ATP) through a series of complex processes known as cellular respiration. Fructose also known as 'fruit sugar' which found in foods such as fruit, honey, some vegetables and soft drinks. Galactose is a component of lactose which is known as the 'milk sugar' and can be found in foods such as legumes, dairy products and dried figs. Dextrose 5% in water is injected into a vein through an IV to replace lost fluids and provide carbohydrates to the body. Dextrose 5% in water is used to treat low blood sugar (hypoglycaemia), insulin shock, or dehydration (fluid loss).

          Next, the second class is disaccharides which are formed when two monosaccharides join together by the dehydration synthesis reaction resulting in a glycosidic bond between the two monosaccharide molecules. The reaction produces water as a side product. The four major disaccharides are sucrose, lactose, maltose and cellobiose. Sucrose provides our body with the energy required to perform physical and mental functions. Our body breaks down foods such as sucrose and starch into fructose and glucose during digestion. The fructose and glucose are metabolized by our body to release energy to your cells. Moreover, sucrose also contributes to a major element in confectionery, desserts and cooks purpose. The uses of sucrose are for sweetening in which its fructose component, that has almost double the sweetness of glucose, makes sucrose distinctively sweet in comparison to other carbohydrates. It can also act as a food preservative when used in sufficient concentrations. Lactose is a type of sugar, naturally found in milk and dairy products.Lactose-free milk has the same nutrient profile as regular cow's milk, so we still get the same vitamins, minerals, calcium, and protein, without the discomfort. Studies have found that a diet which includes low-fat dairy products may lower our blood pressure and decrease our chances of developing type 2 diabetes. In the intestine, lactose is transformed by lactase, an enzyme, into glucose and galactose, both simpler sugars, which are used by our body for energy and various functions. Maltose is a disaccharide that is made up of two glucose units and classified as reducing sugar. It is useful in making hard candies and an inexpensive sweetener. Maltose is found in starchy grains, vegetables and fruits. It is useful as a low-cost sugar source in the form of high-maltose corn syrup. Cellobiose is a disaccharide with the formula C₁₂H₂₂O₁₁. Cellobiose, a reducing sugar, consists of two β-glucose molecules linked by a β(1→4) bond. Cellobiose can be used as an indicator carbohydrate for Crohn's disease and malabsorption syndrome.

          The third class is polysaccharides. There two types of polysaccharides which are homopolysaccharides (all one type of monomer) such as glycogen, starch, cellulose, chitin and heteropolysaccharides (different types of monomers) for instance hemicellulose, peptidoglycans and glycosaminoglycan. Starch is made of polymers of α-D-glucose units and known as the principal food reserve in plants whereas glycogen is the storage polysaccharides in animal. Chitin is the main component of the cell walls of fungi, the exoskeletons of arthropods such as crustaceans, crabs, lobsters and shrimps and insects. Cellulose is the principal food reserve in plants while hemicellulose function as supporting material in the cell wall. Glycosaminoglycan's natural uses in the body include heparin as an anticoagulant, hyaluronate as a component in the synovial fluid lubricant in body joints, and chondroitin which can be found in connective tissues, cartilage and tendons while peptidoglycan provides rigid support to bacterial cells and maintains the characteristic shape of the cell. Peptidoglycans also allows bacterial cell to withstand media of low osmotic pressure, such as water.

I create a mind map on the topic of CARBOHYDRATES to make it easier for me to refer back in the future.