Biological experiment report

Experimental Identification of reducing sugars, fats and proteins in biological tissues 1. Experimental purposes The basic methods for identifying reducing sugars, fats and proteins in biological tissues were initially grasped.
Second, the experimental principle
1. Principles of Identification of Reducing Sugars There are many types of reducing sugars commonly found in biological tissues, such as glucose, fructose, and maltose. They contain a reducing group in the molecule and are therefore called reducing sugars. There is no free hemiacetal hydroxyl group in the molecule of sucrose, so it is called non-reducing sugar and has no reducing property. In this experiment, the use of the Feilin reagent can only detect the presence or absence of reducing sugars in biological tissues, but not the non-reducing sugars.
The Feilin reagent was prepared from a sodium hydroxide solution having a mass concentration of 0.1 g/mL and a copper sulfate solution having a mass concentration of 0.05 g/mL. When mixed, a pale blue Cu2 precipitate was formed immediately. Cu2 and added glucose can form a brick red Cu2O precipitate under heating, while glucose itself is oxidized to gluconic acid. Its reaction formula is as follows:
CH2OH—4—CHO+2Cu2→CH2OH—4—COOH+Cu2O↓+2H2O
When the reducing sugar is identified by the Ferien reagent, the color change of the solution is: light blue brown brick red.
2. Principles of Protein Identification When identifying whether a protein contains protein in a biological tissue, a biuret method is commonly used, and a biuret reagent is used. The biuret reagent was composed of a sodium hydroxide solution having a mass concentration of 0.1 g/mL and a copper sulfate solution having a mass concentration of 0.01 g/mL. In an alkaline solution, the biuret can react with Cu2+ to form a purple or purplish red complex. This reaction is called a biuret reaction. Since the protein molecule contains many peptide bonds similar in structure to the biuret, the protein can react colorally with the biuret reagent.
3. The principle of fat identification Fat can be dyed orange in Sudan III, dyed red by Sudan IV. Experimental procedure IV. Laboratory supplies

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Five, pay attention to
1. For the experiment of identifying reducing sugars, when heating the solution in the test tube, the upper part of the test tube should be clamped with a test tube holder and heated in a large beaker of blooming water. Note that the bottom of the test tube should not touch the bottom of the beaker, and the test tube should not be directed toward the experimenter, so as to avoid rushing out of the test tube when the solution in the test tube boils, causing burns. If the solution in the tube is too boiling, lift the tube holder and leave the bottom of the tube out of the boiling water in the large beaker.
2. The mixture of liquid A and liquid B of the Feilin reagent can be used after mixing. Do not add the liquid A and the liquid B to the tissue sample solution.
3. In the identification of the protein, first add biuret A, then add biuret B
6. What is the basis for the identification of reducing sugars, fats, and proteins in biological tissues?