Triacylglycerols

Triacylglycerols

• Triester of glycerol with three ester groups

• Serve as energy storage and are concentrated primarily in special cells called adipocytes

Hydrolysis

• Reverse of the esterification reaction by which it was formed

• Water is used to breakdown subtances into their simpler forms

Hydrogenation

• Produces the solid shortening in store

• Source of trans fatty acids

• Unsaturated to Saturated

• Removal of double bond by adding hydrogen

Saponification

• Oldest known chemical reaction

• Produced glycerol and a mixture of fatty acid sodium salts called salt

Biological Membranes

• Constitutes the main components of the membrane

• In an aqueous solution, complex lipids spontaneously form into a lipid bilayer with back-to-back arrangement of lipid monolayers

Fluid

• Free later motion in the bilayers makes membranes liquid like

• Lipid part serves as a barrier against movement of ions or polar compounds into and out of the cell

Phopholipids

• Alcohol (platform molecule) + two fatty acids + phosphate

• Up to 80% of the mass of a cell membrane and are primarily phospholipids

• Emulsifiers | Cellular barrier | Pathway for various substances across membranes

• Soybean | eggs | milks

Glycerophospholipids

• Also known as phosphoglycerides

• Structurally similar to fats

• Second most abundant group of naturally occurring lipids

Lecithin

• If the other alcohol is choline, it is called phosphatidylcholine

• Major component of egg yolk

Cephalin

• Similar to lecithin but different alcohol is involved

• They contain alcohols such as ethanolamine or serine

• Blood coagulation | heart, liver, brain | sourced from egg yolks

Phosphatidylinositol

• The alcohol is bonded to the rest of the molecule by a phosphate ester bond

Sphingolipids

• Myelin, the coating nerve of axons, contains a different kind of complex lipid

• Alcohol portion is sphingosine

• Involved in cell growth, differentiation, and apoptosis

Ceramide

• Combination of fatty acid and sphingosine

• Many are also found in cerebrosides

Glycolipids

• Contains carbohydrates and ceramides

• Maintain cell membrane stability, tighten and minimize the look for sagging pores and rough bumps

Cerebrosides

• Ceramide mono-or oligosaccharides

Gangliosides

• Complex sphinoglycolipids that contain branched chains of up to seven monosaccharide residues

• Occur in the gray matter of the brain and myelin sheath

Steroids

• A group of plant and animal lipids that contains this tetracyclic structure

Cholesterol

• Most abundant steroid in the human body, and also the most important

Lipoproteins

• Carrier of cholesterols

• HDL - good cholesterol

• LDL - bad cholesterol

Female sex hormones

• Synthesized in the female ovaries from progesterone

• Responsible for the development of female secondary sex characteristics and control of menstrual cycle

Mineralocorticoids

• Control the balance of Na and K ions in the cell

Glucocorticoids

• Synthesized in the adrenal cortex

• Regulates the carbohydrate metabolism

• Involved in the reaction to stress

Bile salts

• Oxidation products of cholesterol

• Synthesized in the liver and stored in the gall bladder

Prostaglandins

• Family of compounds that have 20-carbon skeleton of prostanoic acid

• Made at sites of tissues damage or infection that are involved in dealing with injury and illness

Thromboxane

• Derived from arachidonic acid

• Induces platelet aggregation and vasoconstriction

Leukotrienes

• Derived from arachidonic acid

• Mainly occur in leukocytes