Biochemistry of Lipids and Lipoproteins

The process of adding two carbons to a fatty acid chain, typically starting with palmitoyl-CoA (C16).

An enzyme required for fatty acid elongation, converting palmitoyl-CoA to stearyl-CoA (C18).

The primary source of the two carbon units used in fatty acid elongation. It's essential for lengthening the fatty acid tail.

NADPH plays a vital role in reducing the newly formed 3-Ketoacyl-CoA to 3-Hydroxyacyl-CoA during fatty acid elongation. It provides the necessary reducing equivalents.

Fatty acids can be elongated in mitochondria, but it's less active than in the endoplasmic reticulum. This process typically occurs with shorter fatty acid chains.

The process of introducing double bonds into long chain fatty acids, converting saturated fatty acids into unsaturated ones.

Fatty acids that cannot be synthesized by human body and must be obtained from the diet.

The two essential fatty acids required by humans, that cannot be synthesized by the body.

A primary lipid in the body, composed of a glycerol molecule attached to three fatty acid chains. It serves as an efficient energy storage molecule, providing more energy per gram than carbohydrates.

A major component of cell membranes, consisting of a glycerol molecule attached to two fatty acid chains and a phosphate group with a head group. Phosphate and head group give it its unique properties.

The enzyme responsible for catalyzing the first step in triacylglycerol synthesis by converting glycerol to glycerol-3-phosphate using ATP.

The enzyme that adds a fatty acid molecule to glycerol-3-phosphate, forming 1-acyl glycerol-3-phosphate (lysophosphatidic acid), an intermediate in the synthesis of both triacylglycerol and glycerophospholipids.

A key intermediate in the synthesis of both triacylglycerol and glycerophospholipids. It is formed by adding a second fatty acid to 1-acyl glycerol-3-phosphate.

A major source of glycerol-3-phosphate in liver cells. This molecule is involved in glycolysis.

A lipoprotein synthesized in the liver that transports triacylglycerol and other lipids from the liver to other tissues. It's like a bus for fats.

The process of breaking down stored triacylglycerol to release fatty acids and glycerol, providing energy when needed.

A major lipid found in myelin, the protective coating around nerve fibers. It's composed of ceramide and galactose.

A major glycolipid found outside of nerve tissue. It serves as a precursor for more complex glycosphingolipids.

They are complex glycolipids that contain a branched chain with a variety of sugars, including sialic acid.

It's a critical intermediate in the biosynthesis of both galactocerebroside and glucocerebroside. It's made by attaching a fatty acid tail to a sphingosine backbone.

The process of building up glycolipids from ceramide by adding various sugars like glucose, galactose, and sialic acid.

A common intermediate in the synthesis of glycerophospholipids and triacylglycerols.

The starting point for synthesizing phosphatidate, it's formed by reducing dihydroxyacetone phosphate (DHAP) and to a lesser extent by phosphorylating glycerol.

A key molecule in the synthesis of phosphatidylserine and phosphatidylinositol. It's an activated form of phosphatidate.

A lipid containing serine, formed from CDP-diacylglycerol or from phosphatidylethanolamine and serine.

A lipid containing inositol, formed from CDP-diacylglycerol.

A lipid containing choline, synthesized from CDP-choline and diacylglycerol.

A lipid containing ethanolamine, synthesized from CDP-ethanolamine and diacylglycerol.

Active form of choline, involved in phosphatidylcholine synthesis. It's formed from choline and CTP.

Triacylglycerol produced in the liver is packaged with cholesterol, phospholipids, and proteins (apolipoprotein, apoB-100) to form VLDL and released into the bloodstream for delivery to peripheral tissues.

Lipoprotein lipase, located on blood capillary walls, hydrolyzes VLDL triacylglycerol into free fatty acids and glycerol.

Hormone-sensitive lipase, found in adipose tissue, hydrolyzes stored triacylglycerol into free fatty acids and glycerol.

Glycerol cannot be metabolized by adipocytes due to the lack of glycerol kinase. It's transported to the liver for phosphorylation.

Phospholipids are major membrane lipids composed of glycerol (glycerophospholipids) or sphingosine (sphingophospholipids) backbones.

Phosphatidylserine, phosphatidylinositol, phosphatidylcholine (lecithins), phosphatidylethanolamine (cephalins), cardiolipin (diphosphatidylglycerol), and plasmalogens are examples of glycerophospholipids.

Sphingomyelin is an example of a sphingophospholipid.

The initial steps in glycerophospholipid biosynthesis are similar to those of triacylglycerol synthesis.

A sphingophospholipid with a sphingosine backbone instead of glycerol. It has a phosphate group and choline head group attached to ceramide.

The building block of all sphingolipids. It's formed in the ER by condensing palmitoyl-CoA with serine.

A glycosphingolipid with a glucose or galactose attached to ceramide. It's the simplest type of glycosphingolipid.

A type of glycolipid derived from ceramide, featuring a sphingosine backbone with a fatty acid attached to the amino group. It has sugar residues attached to its terminal hydroxyl group.

Type of glycosphingolipids that contain a sulfate group on the sugar residue - typically galactose. They are abundant in the brain and myelin sheath.

A family of complex glycosphingolipids with multiple sugar residues, including glucose, galactose, and N-acetylgalactosamine. They are found in cell membranes and play roles in cell recognition and signal transduction.

The most complex type of glycosphingolipid. They have a core structure similar to globosides but contain sialic acid (N-acetylneuraminic acid) residues. They act as receptors for various hormones and neurotransmitters.

The process of synthesizing sphingomyelin, which occurs in the Golgi apparatus. It involves the transfer of a phosphocholine group from phosphatidylcholine to the ceramide molecule.