Lipid PDF - Biochemistry Practical

Biochemistry Practical Lipids are organic substances soluble only in organic solvents like chloroform, ether and benzene but insoluble in water and polar solvents. Function : 1. Lipids are structural components of cell membrane and nervous tissue. 2. Lipids present under skin act as thermal insulat...

Biochemistry Practical Lipids are organic substances soluble only in organic solvents like chloroform, ether and benzene but insoluble in water and polar solvents. Function : 1. Lipids are structural components of cell membrane and nervous tissue. 2. Lipids present under skin act as thermal insulator against cold. 3. Lipids are energy source for man like carbohydrates. 4. Lipids like steroids function as hormones. 5. Lipids are part of lipoproteins present in blood plasma. 6. Absorption of lipid soluble vitamins requires lipids. Fatty acids: They are the building blocks of lipids. They are a long hydrocarbon chain containing a carboxyl group at its end. Fatty acids differ from one another in the length of their chain and in the number and location of their unsaturated bonds. Fatty acids are divided into: saturated fatty acids and unsaturated fatty acids, which contain double bonds. Classification of lipids : Based on composition lipids are classified into 1- Simple Lipids : include neutral lipids and waxes. 2- Complex Lipids : include phospholipids , Glycolipids and Sphingolipids. 3- Derived Lipids : include cholesterol (steroids) and lipids-soluble vitamins.  Iodine Test Name experiment : Iodine test The aim of experiment : To distinguish between saturated and unsaturated fatty acids The fatty acids found in animal fats are completely saturated, while those found in vegetable oils contain one or more double bonds. Adding iodine to the double bonds in unsaturated fatty acids, it leads to saturation and the disappearance of the color of the iodine solution, while iodine appears when added to saturated fatty acids. Materials and tools: oleic acid, stearic acid Test tubes Procedure: Add three drops of iodine solution to about 2 ml of each of the previous solutions. Observe what happens and explain your observation. tube color Conclusion Oleic acid Stearic acid