Lipids

Lipids • any fat-soluble (lipophilic), naturallyoccurring molecule, • E.g fats, oils, waxes, • cholesterol, sterols, • fat-soluble vitamins • monoglycerides, diglycerides, phospholipids,

biological functions • energy storage, • as structural components of cell membranes,

• fats are a subgroup of lipids called triglycerides. • Lipids also encompass molecules such as fatty acids and their derivatives • monoglycerides and phospholipids • sterol-containing metabolites

fatty acid • fundamental categories of biological lipids • building block of more structurally complex lipids. plays an important role in the structure and function of cell membranes

Glycerolipids

• composed mainly of mono-, di- and trisubstituted glycerols • E.g : triglycerides • function as a food store, • the bulk of storage fat in animal tissue

Glycerophospholipids phospholipids, key components of the lipid bilayer of cells, in metabolism and cell signaling • Neural tissue contains relatively high amounts of glycerophospholipids

Sterol lipids, • • • -

cholesterol and its derivatives, important component of membrane lipids biological roles hormones and signaling molecules eg: estrogen progesteron androgen testesteron vitamin D

Biological Functions • Membranes • Eukaryotic cells are compartmentalized into membrane-bound organelles. • the main structural component of biological membranes,

Energy storage • Triacylglycerols, stored in adipose tissue, :major form of energy storage in animals.

fat-soluble" vitamins • The " (A, D, E and K) – • are essential nutrients stored in the liver and fatty tissues,

Biosynthesis • In oversupply of dietary carbohydrate, • the excess carbohydrate is converted to triacylglycerol. (lipogenesis.)