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This experiment is to investigate the properties of some carbohydrates, including monosaccharides and disaccharides , physically, functionally and sensually.

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Introduction

By y.c. pong Introduction: Carbohydrates are important in human diet. This experiment is to investigate the properties of some carbohydrates, including monosaccharides and disaccharides , physically, functionally and sensually. Expt 1 relative solubility of carbohydrates, glucose, galactose and lactose Aim: To determine the relatives solubility of glucose, galactose and lactose by measure their saturation point at room temperature and pressure. Principle and procedure: By adding carbohydrates ( glucose , galactose and lactose)into a known volume of water, until no more sugar can be dissolve by water. The solution is considered to be saturated. Solubility means the amount of substance that can be dissolve in a given amount of solvent.so the saturation point can represent the solubility, expressed in mg/ml . By do the test of glucose, galactose and lactose, their relative solubility can be compared. Data: 1st Mass of beaker (g) Mass of beaker + water(g) Final mass (g) Saturation point (mg/ml) ...read more.

Middle

The experiment is not carry out exactly at room temperature (25 c) and the temperature is not keep constant throughout the experiment. 2) There are solution "stick" onto the surface of magnetic stirrer. Precaution and improvement of experiment: 1) Start the magnetic stirrer slowly to avoid splash out of solution. 2) Keep a rough record of approximate quantitives added from time to time as it is useful to guide for future addition in the second times. 3) Allow more time for carbohydrates to dissolve because when approaching the saturation point, the carbohydrates dissolve quite slow. 4) Avoid and unnecessary transfer of solution using container to reduce the lost of substances. Result : The saturation point of glucose is 639.1 mg/ml, Galactose is 189.4 mg/ml and that of lactose is 40.4 mg/ml. Discussion : All sugars are soluble in water because of the present of hydroxyl group, forming hydrogen bond with water molecules. ...read more.

Conclusion

Take respiration of cell as an example, the process is start with glycolysis. The glucose move to cytosol and the molecules are split into two pyruvates, to prepare for the breakdown to provide energy. The high solubility of glucose, make it easy to transport in the bloodstream to their destination. For example, glucose can transport to brain and directly utilized as an energy sources by brain cell. Lactose has a low solubility in water. Human breast milk contains high content of lactose. After milk has been eaten, as lactose has low solubility, the lactose can stay in the ileum for a longer time rather than drift away like liquid quickly. This increase the time for lactase to break down lactose into glucose and galactose, hence have a more effective absorption. Moreover, the lactose's low solubility makes lactose absorption slower. So lactose is safe to consume by diabetes human, since lactose won't cause a fast increase in blood glucose level. ...read more.

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