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Carbohydrates are naturally occurring organic compounds containing carbon, hydrogen and oxygenwith oxygen in the ratio 1:2 as in water.  The general molelcular formula of carbohydrates is Cx(H2O)y  or  CxH2yOy.  Carbohydrates are generally polydroxyl aldehydes, ketones or any compound that on hydrolysis yields any of the polyhydroxides.  They are synthesized in green plants by photosynthesis.   CLASSIFICATION OF CARBOHYDRATES Carbohydrate Simple sugar                             Complex sugar (polysaccharides) Monosaacharide           Disacharides                   e.g. starch cellulose e.g. glucose                  e.g sucrose   EVALUATION Define carbohydrates. State one example each of simple sugar and complex sugar.   MONOSAACHARIDES Monosaacharides are simple sugar with three to six carbon atoms per molecule.  The most common and important of these are the ones with six carbon atoms per molecule called the HEXOSES. They have the same molecular formula C6H12O6 but different spatial arrangement.  Examples include glucose, fructose, galatose and mannose.   GLUCOSE (C6H12O6) Glucose, commonly known as grape sugar or… Read More »CARBOHYDRATES



DISACCHARIDES – WELL EXPLAINED These contain two monosaccharide units. The chemical process through which a large molecule (e.g a disaccharide) is formed from smaller molecules is called condensation and it involves loss of water Common examples of disaccharides include sucrose, maltose and lactose   Disaccharides are broken into their monosaccharide units by heating with dilute hydrochloric acid This is known as hydrolysis and involves addition of water molecules The same process takes place inside cells through enzymes Sucrose + water = hydrolysis—————–glucose+fructose Properties of Disaccharides Sweet tasting Soluble in water Crystallisable Maltose and lactose are reducing sugars while sucrose is non-reducing sugar Sucrose is the form in which carbohydrate is transported in plants: This is because it is soluble andjchernically stable Sucrose is a storage carbohydrate in some plants e.g sugar-cane and sugar-beet Disaccharides are hydrolysed to produce monosaccharide units which are readily metabolised by cell to provide energy.  … Read More »DISACCHARIDES – WELL EXPLAINED

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