Cholesterol biosynthesis

Cholesterol is a waxy steroid metabolite found in the cell membranes and transported in the blood plasma of all animals. It is an essential structural component of mammalian cell membranes, where it is required to establish proper membrane permeability and fluidity. In addition, cholesterol is an important component for the manufacture of bile acids, steroid hormones, and several fat-soluble vitamins. Cholesterol is the principal sterol synthesized by animals, but small quantities are synthesized in other eukaryotes, such as plants and fungi. It is almost completely absent among prokaryotes, which include bacteria. Source: [[wikipedia:Cholesterol|Wikipedia]]

胆固醇是一种存在于动物细胞膜中，并在血液血浆中运输的蜡质类固醇代谢产物。它是哺乳动物细胞膜不可或缺的结构成分，对于建立适宜的膜渗透性和流动性至关重要。此外，胆固醇是胆汁酸、类固醇激素以及多种脂溶性维生素合成的重要成分。胆固醇是动物合成的主要类固醇，但在其他真核生物如植物和真菌中也少量合成。在包括细菌在内的原核生物中，胆固醇几乎完全缺失。信息来源：[维基百科：胆固醇](https://zh.wikipedia.org/wiki/Cholesterol)