1. Glycolipid
Lipids that are composed of fatty acids, glycerol and carbohydrates (glucose) are called glycolipids. This is known as glycocalyx. Such as Cerebron, Nervon etc. Dr. Siddiq Publications
Different types of glycolipids are-
(i) Cerebroside: A glycolipid composed of glycerol, fatty acids and glucose or galactose is called cerebroside. It resides in the animal brain.
(ii) Sulphatide: A glycolipid composed of glycerol, fatty acid and sulphate is called sulphide. It is present in kidney, liver, salivary gland, testis, chloroplast etc.
(iii) Gangliosides: Glycolipids composed of glycerol, fatty acids and oligosaccharides are called gangliosides. It is in the animal’s brain, nerve cells, spleen and red blood cells.
Functions of glycolipids
(i) Glycolipids are used as markers in cell interactions.
(ii) It plays a role in the immune response of the body by recognizing the virus.
(iii) It forms the membrane of chloroplast.
(iv) Participates in the process of photosynthesis.
(v) Galactose combines with lipids to form galactolipids.
(vi) Glycolipids form human blood group.
(vii) This lipid is found in cotton and sunflower seeds.
(viii) It forms the myelin sheath of neurons.
2. Phospholipid
Lipids that are composed of fatty acids, glycerol and phosphate are called phospholipids. Its constituents are phosphotidic acid. Lecithin when the phosphate group of phospholipid is esterified with choline and serine when esterified with hydroxyl gives cephalin. Lecithin was the first phospholipid identified. Phospholipid holo-lecithin, cephalin, plasmalogen, choline, serine, cardiolipin, sphingomyolin etc.
Phospholipids are of three types. These are-
(i) Phosphoglycerides: Phospholipids composed of glycerol, fatty acids and phosphoric acid are called phosphoglycerides. It is present in the cell membrane. Such as lecithin. Dr. Siddiq Publications
(ii) Phosphoinositide: Phospholipids composed of glycerol, fatty acids, phosphoric acid and inositol are called phosphoinositides. It is present in the brain. It is found in soybeans.
(iii) Phosphosphingoside: Phospholipids composed of fatty acids, phosphoric acid and sphingosine are called phosphosphingosides. It resides in the nervous system of animals.
Functions of phospholipids
(i) Phospholipid forms the membrane of cell mitochondria, chloroplast, tonoplast, endoplasmic reticulum, nucleus etc.
(ii) It regulates cell permeability and transport processes.
(iii) Acts as a prosthetic group in some enzymes.
(iv) It helps in coagulation or coagulation of blood in the animal body.
(v) It acts as cell ion. Blocks diffusion of glucose, water and charged ions.
(vi) It increases the rate of oxidation.
(vii) It plays an important role in acetylcholine neurotransmission.
(viii) It helps in jasmonic acid production in plant cells. Jasmonic acid participates in disease prevention.
(ix) It maintains the internal stability of the cell.
3. Lipoprotein
Lipids that are composed of fatty acids, glycerol and proteins are called lipoproteins. These lipids are present in the membranes of mitochondria and chloroplasts. It is involved in the electron transport system of mitochondria and generates energy. Lipoproteins are present in plasma, egg yolk and milk. Example- Cutin, Suberin etc.
There are 5 types of lipoproteins. These are-
(i) Chylomicron: Chylomicron is a lipoprotein particle composed of fat and protein. It acts as a carrier of cholesterol.
(ii) VLDL : Very Low Density Lipoprotein is called VLDL. It is very low density lipoprotein.
(iii) IDL : Intermediate Density Lipoprotein is abbreviated as IDL. It is medium density lipoprotein.
(iv) LDL : Low Density Lipoprotein is abbreviated as LDL. It is low density lipoprotein. The normal level of cholesterol in the blood is 0.15-1.20%. High levels of LDL in the blood are harmful (<100 mg/dl). LDL carries about 1500 cholesterol esters per molecule. If the level of cholesterol in the blood is high, it accumulates in the lining of the blood vessels and narrows the blood flow. It increases blood pressure in the body and reduces blood flow. As a result, blood flow to the heart decreases and heart disease occurs. If its level is high, the person becomes unconscious. Chest pain. A heart attack may occur. Heart failure occurs. Coronary thrombosis may occur. Generally men have higher LDL and women have lower. LDL is called bad cholesterol).
(v) HDL : High Density Lipoprotein is abbreviated as HDL. It is high density lipoprotein. It is good to have high levels of HDL in the human blood (40