检测生物组织中的糖类、脂肪和蛋白质（Detect sugars, fats, and proteins in biological tissues）.docVIP

检测生物组织中的糖类、脂肪和蛋白质（Detect sugars, fats, and proteins in biological tissues） Experiment two: detecting carbohydrates, fats and proteins in biological tissues First, the purpose of the experiment: Try to use sugar, fat and protein detection of biological tissue in chemical reagents, explain the principle of color reaction, memorizing and distinguish specific color reagent soluble reducing sugar, fat, protein identification and for generating the basic identification of the preliminary master compound method to describe the experimental phenomena, grasp the method of using NaOH and CuSO4 solution the. Two. Experimental principle: certain chemical reagents can make organic compounds in biological tissues produce specific color reactions. 1. There are more soluble sugars in biological tissues, including glucose, fructose, maltose and sucrose. The molecules of the first three sugars contain a free, reduced hydroxyl radical, which is therefore called reducing sugar; no sugar in the sucrose molecule; non reducing sugar. The Fehling reagent used in the experiments, soluble reducing sugar can only be identified in biological tissue, and can not identify the soluble non reducing sugar. Soluble sugar (such as glucose, fructose, maltose) interact with Fehling reagent 2O can generate Cu, brick red precipitate. Such as: Glucose + 2Cu2+ + 4OH + Cu 2O: heating gluconate (red brick) + H 2O That is, Cu 2+ is reduced to Cu 2O, and glucose is oxidized to gluconic acid. Reducing sugar by Fehling reagent identification, solution change process: light blue, brown, brick red precipitate. Starch changes into blue (straight chain) or purple (red) color (branched chain) when it is iodine. 2, fats and lipids (phospholipids, glycolipids, sterols, lipids, etc.) are collectively referred to as lipids. It is a normal component of human tissue, insoluble in water and soluble in alcohol, ether, chloroform and other aliphatic solvents. In chemistry, lipids are esters of fatty acids or substances relate