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