1. Oil (triglyceride)
2. Lipids (phospholipids, sterols)
Grease action
Adipose tissue is a tissue specially used to store fat in the body. When the body needs energy, the fat stored in adipose tissue cells can be mobilized and decomposed to supply the body with what it needs. In addition, the fat in higher animals and human body can also reduce body heat loss, keep body temperature constant, reduce friction between internal organs and buffer external pressure.
Lipid action
Cells are divided into organelles/nuclei and other compartments to ensure that multiple metabolic activities are carried out at the same time without interfering with each other and maintain the normal structure and function of cells.
chemical composition
Lipids, also known as lipids, are the general names of fats and lipids. They are nonpolar organic solvents, insoluble in water and soluble in fatty solvents (alcohol, ether, chloroform, benzene). And can be used by the body. Lipids include a wide range and there are many classification methods. Lipids are usually divided into simple lipids, complex lipids, derived lipids and unsaponifiable lipids according to their main components.
Lipids include a variety of molecules, mainly composed of carbon and hydrogen with nonpolar valence bonds. Because these molecules are nonpolar, they are incompatible with water, so they are hydrophobic. Strictly speaking, lipids are not macromolecules, because their relative molecular mass is not as large as that of sugar, protein and nucleic acid, and they are not polymers.
function
store energy
It is the best way to store energy, such as triglycerides of animals and oilseeds. By comparing the following data, we can draw a conclusion:
Comparison of two energy substances (sugar and lipid) in the body
Energy supply per unit weight: sugar 4. 1 kcal/g, fat 9.3 kcal/g.
Storage capacity: 1 glycogen or starch: 2 water, while fat is relatively pure and much smaller.
In the order of utilization: sugar is consumed first, and then lipid is consumed. So many weight loss/slimming principles, such as breaking the valley, all come from this.
Skeleton of biofilm
Liquid mosaic model of cell membrane: phospholipid diester layer, cholesterol, protein, glycolipid, glycerophosphate and sphingomyelin.
Electrical and thermal insulators
Animal adipose tissue has protective functions such as heat preservation and mechanical stress prevention, and vegetable wax can prevent water evaporation.
Electrical insulation: sheath cells of nerve cells, sheath of electric wires, and short circuit of nerves.
Insulation: keep warm in winter, penguins, polar bears, etc.
other
Signal transmission: steroid hormones.
Enzyme activator: lecithin activates β -hydroxybutyrate dehydrogenase.
Glycosyl carrier: Polyphenol phosphate is used as the carrier of carbonyl group when glycoprotein is synthesized.
Precursors of hormones, vitamins and pigments (terpenes, sterols).
Growth factors and antioxidants.
Participate in signal recognition and immunity (glycolipid).