Part B: Hydrolysis of sucrose Experimental background saccharides are The glycos
ID: 213067 • Letter: P
Question
Part B: Hydrolysis of sucrose Experimental background saccharides are The glycosidic bonds which join sugar units together in disaccharides and in poly highly specific. In biological systems this process is usually enzymat highly specific for the glycosidic bonds they hydrolyze. In the laboratory we can such as sucrose non-enzymatically with dilute HCl in a few minutes ic and some of the enzymes are hydrolyze carbohydrates 12.1.4 Procedure Non-enzymatic hydrolysis of sucrose: Place1 ml of sucrose marked "C" for control and "E fore place both the tubes in a beaker of boil "E" to neutralize the HCI. Add 5 ml of Benedict's solution to both the tubes, mix, and heat the tube in a boiling water bath for 5 minutes. Note the result below: solution in two large test tubes previously xperimental. Add 10 drops of 6N HCI only to tube "E". Mix and ing water for 10 minutes. Add 10 drops of 6N NaOH only to tube f 12.1.5 Data analysis Provide reasons for the negative and positive results in the control and experimental tubes for non- enzymatic and enzymatic hydrolysis of sucrose. Non-enzymatic hydrolysis: Control: Biu nonre doin Evperimenal: Das/Brown ) nPreciptatt. redu Part C: Colorimetric characterization of unknown sugars 12.1.6 Procedure Using the following color tests, identify the sugars in unknown solutions marked as s C, D, E and F. These solutions may contain a polysaccharide (amylose or starch), a non-carbo disaccharide (sucrose), a monosaccharide (fructose), monosaccharide (glucose), and a (ribose). One drop of Molisch reagent is added to 1 ml of the unknown mm test tube. The tube is then tilted and 0.5 ml of concentrated sulfur sanExplanation / Answer
Benedict's solution is used to determine the presence of reducing and non-reducing sugars in the given solution. Reducing sugars will reduce copper sulphate present in the Benedict's solution to form a precipitate (cuprous oxide), changing the blue color of the Benedict's solution to red color depending on the amount of the reducing sugar present. Non-reducing sugars does not contain free aldehyde or ketone groups in them to carry out this reaction. Hence they remain blue in color.
In the control tube, only Sucrose is present which is a non-reducing sugar. Hence addition of Benedict's solution showed no reaction with sucrose and hence it remained blue in color showing Negative reaction.
In the experimental tube, Sucrose is treated with HCl. HCl hydrolysis sucrose to form glucose and fructose both of which are reducing sugars. Hence when Benedict's solution is added to this mixture of glucose and fructose, the copper sulphate in the Benedict's reagent is reduced to cuprous oxide and gets precipitated. The blue color of the Benedict's reagent is changed to reddish brown color due to this reduction reaction and therefore it shows Positive reaction.