Biomolecules & Polymers Lipids

University:
California State University, Chico
Course:
CHEM 370 | Organic Chemistry II
Academic year:

2022
Views:

213

Pages:

3
Author:

Lance Gutierrez

BIOMOLECULES & POLYMERS LIPIDS (a) Lipids words is derived from greek word lipos which means fat. (b) Lipids are heterogeneous group of substances which have common property of being relatively insoluble in water and soluble in non-polar solvents such as ether, Chloroform etc. (c) Form 3-5% part of protoplasm. (d) H2O  2 : 1 (different from water) (e) Ratio of oxygen is less. (f) Specific gravity < 1 Three types Simple Compound Derived SIMPLE LIPID Simple lipid two types Natural fats or Triglycerides Wax TRIGLYCERIDES (a) These are esters of fatty acids with glycerol. Ester bond is present (b) Synthesis is of following typeH H H C OH H–O–O–C–R H C OH + H–O–O–C–R H C OH H–O–O–C–R H H Glycerol Fatty Acid H H H–C–O–O–C–R 3H2O H–C–O–O–C–R H–C–O–O–C–R H H Fats (c) Fatty acids which occur in natural fats usually contain an even number of carbon atoms(4 to 30) in straight chains. (d) Simplest fatty acid HCOOH. (e) More complex fatty acid are formed by successive addition of –CH2 groups. Fatty acids are of 2 types Saturated Unsaturated (i) Saturated :  Only single bond is present in them.  First member is CH3COOH. Other examples :  Palmitic acid - C15H31COOH  CH3(CH2)14 COOH  Stearic acid - C17H35COOH  CH3(CH2)16COOH  Palmitic and stearic acid is found in fats of animals in less amount.  These are solid and are found in fats. (ii) Unsaturated :  Double bond is present in these fatty acid chain.  These are liquids at room temperature. Found in Oils.  These are of two types Monounsaturated - 1 Double bond is present Ex. Oleic acid.  Oleic acid is present in more amount in nature. Polyunsaturated - More than two double bond Ex. Linoleic acid with two double bonds Linolenic acid with three double bonds Arachidonic acid with four double bonds (Groundnut) Wax  These are esters of other alcohols of high molecular weight instead of glycerols.  These are insoluble in water.  These are monohydric alcohols.  Some examples of waxes Myricye palmitate (Honeybee wax) Cetyl palmitate (Dolphin and whale wax) Cerumen (ear wax) BIOMOLECULES & POLYMERS Compound Lipid - Are of 4 types : (a) Phospholipids. (b) Glycolipids. Phospholipids : Phosphorous is present. Ex. cell wall Glycolipids  Lipid + Sugar = Glycolipids  Present in brain, Adrenal glands, kidney, WBC liver, thymus, Spleen, Lungs, egg yolk  Glycolipids = 2 Fatty acid + 1 sphinocine + 1 galactose. Derived lipids  By hydrolysis of fats they are obtained Derived lipids Types Steroids Sterols Steroids :  These are different from other fats.  It is insoluble in water. (i) Bile acids :  Present in secretion of liver. (ii) Sex hormones :  These are androsterones. (iii) Adrenal hormone- Eg : Aldosterone Sterols :  They have -OH groups.  They are complex monohydroxy alcohols. Cholesterol - It is widely distributed in all cells of body. Biological importance of Fat :  It is source of energy.  It is important for absorption of vitamin A, D, E and K.  It is important component of plasma membrane.  It act as shock absorber of body.  Calorific value 9.3 kcal.