From this learning unit, I learnt that carbohydrates are the most abundant biological molecules in the body. Its empirical formula is Cn(H2O)n, which also known as hydrates of carbon. The main functions of carbohydrates are used to store energy in the form of starch and glycogen, acts as structural components such as cellulose and chitin. There are also some carbohydrates derivatives such as DNA, RNA and co-factor.
Carbohydrates can be classified into few groups, which are monosaccharides, disaccharides, oligosaccharides and also polysaccharides. They are being classified according to the number of carbon.
From the lecture, I learnt that monosaccharides, which often called as a simple sugar, is the simplest form of carbohydrate. Monosaccharides with the formula C6H12O6, include glucose, galactose, ribose, glyceraldehyde and fructose. Monosaccharides can undergo reduction and esterification, which hydroxyl group of alcohols react with acids to produce esters.
They are used by our body for production of energy. Monosaccharides are building blocks for more complex carbohydrates and they also serve as components to amino acids. Glucose molecules are being broken down in glycolysis process to provide energy and acts as precursor for cellular respiration. Fructose is found in honey, tree and vine fruits, flowers, berries and most root vegetables. It is usually added to our foods and drinks for taste enhancement and improvement browning of some foods. Galactose is a monosaccharide produced in many mammals and can be found in milk and dairy products, sugar beets, and other gums and mucilages. It is a vital constituents of nerve cells membrane. For example, RNA and DNA are building blocks of life and ascorbic acid is derived from glucose. Not only that, sugar substituents such as sorbitol and mannitol are derived naturally from plants and berries in the form of monosaccharides.
There’s are glycosidic bonds which are linkage from anomeric carbon to the –OR group to form disaccharides. Two monosaccharides are joined together by the formation of glycosidic bond. The common examples of disaccharides are maltose, cellobiose, sucrose and lactose. Maltose is the building block of starch and glycogen. Both glycogen and starch consist of D-glucose monomers in α (1-4) linkage with occasional branch points with α (1-6) linkage. It is found in seeds and other parts of plants as they break down their stored energy to sprout. Not only that, foods such as cereals and sweet potatoes contain high amounts of maltose. It can be used in hard candy and frozen desserts due to its unique tolerance to heat and cold. Sucrose is a molecule composed of 2 monosaccharides, which are glucose and fructose. Sucrose is obtained from either sugarcane or sugar beet. Consumption of adequate sucrose ensure your body gets the optimal amount of energy, however, uncontrolled high levels of glucose result in sugar-related diseases such as diabetes and obesity. Lacrosse is a large sugar molecule that is made uo of 2 smaller sugar molecules, which are glucose and galactose. Lactose is found in milk and dairy products. Human milk contains lactose, which provides up to almost 50% of an infant’s energy needs and lactose is the only source of galactose. Lactose plays role in the absorption of calcium and other minerals such as copper and zinc.
Oligosaccharides are polymers of 3 to 10 simple sugars linked together. Chicory root has the most oligosaccharides. It also can be found in varying amounts in onions, legumes, wheat, asparagus, jicama and other plant foods. Manufacturers used oligosaccharides as a partial substitute for fats and sugars to improve product’s texture. It is now exploring to take part in prebiotics. There are some examples of oligosaccharides in food, which are fructo-oligosaccharides (FOS), gentio-oligosaccharadies (produced from pustulan) and pectic oligosaccharides (derived from chitosan).
There are 2 types of polysaccharides, which are HOMOpolysaccharides and HETEROpolysaccharides. HOMOpolysaccharides consists of all one type of monomer such as glycogen, starch, cellulose and chitin, whereas HETEROpolysaccharides consists of different types of monomers such as hemicellulose, peptidoglycans and glycomnoglycans. Polysaccharides play few important roles in storage, structure and information functions.
Starch, which is main food reserve in plants and glycogen, which is storage polymer in animals are classified as storage polysaccharides. There are 2 forms of starch which are amylose and amylopectin. Cellulose, hemicellulose, chitin and glucoaminoglycans are classified as structural polymers to give strength to membrane, cell wall and exoskeleton. Glycoprotein is information polysaccharides, which is a protein that contain oligosaccharide chains covalently attached to polypeptide side-chains and it is an important integral membrane protein.
In conclusion, carbohydrates are very important for human to survive, in order to create energy and energy storage. However, excessive carbohydrates can lead to health problems such as cardiovascular problems, obesity and also diabetes. We need to take all types of carbohydrates but PLEASE DON’T EAT TOO MUCH !!!!
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