Medical Biochemistry - Lipid Metabolism

They are non-covalent assemblies of lipids and proteins, crucial for transporting lipids in the bloodstream.

The core of a lipoprotein particle contains mainly triglycerides and cholesterol esters, while the surface is composed of phospholipids, proteins (apolipoproteins), and cholesterol.

Chylomicrons, very low-density lipoproteins (VLDL), low-density lipoproteins (LDL), and high-density lipoproteins (HDL) are the four major groups, each with a distinct structure and function.

Chylomicrons are responsible for transporting dietary lipids from the intestine to various tissues.

VLDL transports endogenous lipids synthesized in the liver to peripheral tissues.

LDL acts as a major carrier of cholesterol, delivering it to cells throughout the body. High levels of LDL are linked to cardiovascular disease.

HDL plays a protective role, transporting excess cholesterol from peripheral tissues back to the liver for excretion. Higher levels of HDL are associated with a reduced risk of heart disease.

Apolipoproteins are proteins associated with lipoproteins. They play crucial roles in lipoprotein metabolism, including lipid transport, receptor recognition, and activation of specific enzyme.

A type of lipoprotein synthesized in the small intestine responsible for transporting dietary lipids (triglycerides) from the gut to the liver.

A lipoprotein synthesized in the liver that transports endogenous triglycerides (made in the liver) to various tissues.

A lipoprotein primarily formed from VLDL in the blood, responsible for transporting cholesterol from the liver to peripheral tissues.

A group of disorders characterized by elevated levels of plasma lipoproteins.

A type of hyperlipoproteinemia characterized by an increase in plasma chylomicrons due to a deficiency in lipoprotein lipase enzyme.

A type of hyperlipoproteinemia caused by faulty LDL receptors, leading to an accumulation of LDL in the blood.

A type of hyperlipoproteinemia characterized by a deficiency in apo E, affecting the uptake of VLDL and chylomicron remnants.

A type of hyperlipoproteinemia caused by excessive production of triglycerides from carbohydrates.

The process of converting fatty acids into triacylglycerol (TAG). This process is important for storing energy in fat cells.

An enzyme that plays a key role in lipogenesis by attaching fatty acids to glycerol-3-phosphate, forming triacylglycerol.

The process of converting glucose into fatty acids. This process is fueled by insulin and occurs in the liver and adipose tissue.

A hormone that stimulates lipogenesis by increasing the availability of glucose and glycerol-3-phosphate.

The final product of lipogenesis, a storage form of energy composed of three fatty acids bound to glycerol.

A metabolic disorder characterized by high levels of very low-density lipoproteins (VLDL), triglycerides, and sometimes cholesterol in the blood. It results in a turbid plasma appearance.

Lipogenesis primarily takes place in the liver and adipose tissues, with a significant role in brain, kidney, and mammary glands during lactation.

Glycerol-3-phosphate is derived from dihydroxyacetone phosphate, a product of glycolysis, by the action of glycerol-3-phosphate dehydrogenase.

In the liver, glycerol-3-phosphate can be formed from both glucose and glycerol by the enzyme glycerokinase. In adipose tissue, only glucose contributes to glycerol-3-phosphate formation due to the absence of glycerokinase.

Lipogenesis occurs primarily in the cytosol, utilizing Acetyl-CoA as the immediate substrate.

Lipogenesis requires a variety of co-factors, including NADPH, ATP, Mn2+, biotin, and HCO3-

The synthesis of unsaturated fatty acids involves the introduction of double bonds into the fatty acid chain. This process requires specific enzymes (desaturases) and involves the removal of hydrogen atoms from the fatty acid chain.

The main building block for fatty acid synthesis, formed from the breakdown of carbohydrates within the mitochondria.

An important intermediate in fatty acid synthesis, produced from Acetyl-CoA.

A key regulatory enzyme in fatty acid synthesis, converts Acetyl-CoA to Malonyl CoA, crucial for fatty acid synthesis and elongation.

A large multi-enzyme complex that performs the majority of the reactions in fatty acid synthesis.

The final product of fatty acid synthesis, a saturated fatty acid with 16 carbon atoms.

The process of combining Acetyl-CoA and Malonyl CoA, using fatty acid synthase, to create longer fatty acid chains.

A process required for fatty acid synthesis, using ATP and NADPH as energy sources.

A process where fatty acids are activated, allowing them to bind with glycerol-3-phosphate, a crucial step in converting fatty acids to triglycerides.