Lipids are important organic substances in living organisms, besides fats there are phospholipids, steroids and waxes. They play an important role in the membrane structure, growth and development.
It is another type of lipid that is abundant in living organisms. Its structure is similar to that of fats: all the three hydroxyl groups of glycerol in fats attach to fatty acids, while two hydroxyl groups of glycerol in phospholipids attach to fatty acids, and the third hydroxyl group attachs to phosphate group. Some small organic molecules are bonded to the phosphate group to form different phospholipids, such as lecithin and cephalin.
Phospholipids are amphiphilic molecules, which means they are hydrophilic and lipophilic. Fatty acids tails are composed of carbon and hydrogen, and tend to move away from water, while polar phosphate heads will come closer to water. A large number of phospholipids in water form a stable bilayer spherical shell spontaneously: The heads face the outside of the shell and come into contact with water molecules; the hydrocarbon tail face the inside of bilayer shell, away from water and close to the tails of other phospholipids. One of the two fatty acid in the tail is unsaturated and will form a kink. This conformation prevents them from being tightly bound, so the phospholipid bilayer has fluidity.
Animal livers, brains and nerves contain a lot of phospholipids, and soybeans are also rich in them.
They consist of a few carbon rings. Their structures are very different from fats and phospholipids, but they are also soluble in organic solvents and difficult to dissolve in water. steroids are abundant in the animal liver and egg yolk. Common steroids are cholesterol, sex hormones, adrenaline, vitamin D, etc.. They play an important role in the growth and development of organisms.
Cell membrane structure: steroids help to maintain the structural integrity and fluidity of cell membranes in the body. Cholesterol is an important component of cell membranes, where it helps to regulate the permeability and stability of the membrane. It's also a component of HDL and LDL, which transport cholesterol in the blood.
Hormone synthesis: steroids are also involved in the synthesis of many hormones in the body, including sex hormones such as estrogen, progesterone, and testosterone. Sex hormones help your reproductive organs develop and form germ cells..
Vitamin D synthesis: steroids are involved in the synthesis of vitamin D, which is important for bone health and calcium absorption in the body.
Bile acid synthesis: steroids are also involved in the synthesis of bile acids, which are important for the digestion and absorption of fats in the body.
While steroids are important for many physiological functions in the body, it is important to maintain a healthy balance of these compounds. High levels of cholesterol, for example, can increase the risk of heart disease and stroke. It is important to maintain a healthy diet and lifestyle to help regulate cholesterol levels in the body.
It is produced from long-chain alcohols and long-chain fatty acids by a dehydration reaction and is more hydrophobic than fats. Some aquatic birds have wax layer on their feathers to their body dry when they are swimming. Some fruits also secrete wax to cover their surface to avoid water evaporation and microorganism invasion.