The cholesterol biosynthesis pathway is a long one and it requires significant amounts of reductive and ATP energy, which is why it is included here. Cholesterol has important roles in the body in mem...The cholesterol biosynthesis pathway is a long one and it requires significant amounts of reductive and ATP energy, which is why it is included here. Cholesterol has important roles in the body in membranes. It as also a precursor of steroid hormones and bile acids and its immediate metabolic precursor, 7-dehydrocholesterol, is a precursor of Vitamin D. The pathway leading to cholesterol is known as the isoprenoid pathway and branches of it lead to other molecules including other fat-soluble vit