Lipids: triglycerides, phospholipids, and sterols. Ch. 6

Micelle

Water soluble spherical lipid cluster; bile salts create a shell around each cluster, allowing for the structure to be suspended in watery digestive juices.

Choline

Water soluble, vitamin like compound; component of lecithin.

Lipoproteins

Water-soluble structure that transports lipids through the bloodstream.

Monounsaturated fatty acid (MUFA)

fatty acid that has one double bind within the carbon chains.

Major functions of lipids in the body

* provide and store energy * form and maintain cell membranes * produce steroid hormones * insulate the body against cold temperatures * cushion the body against bumps and blows * form body contours * absorb fat-soluble vitamins and photochemicals

Lipoprotein lipase (LPL)

Enzyme in capillary walls that breaks down triglycerides.

Lipases

Enzymes that break down lipids

Arachidonic acid

Essential fatty acid; precursor to some eicosanoids

Saturated fatty acid

Fatty acid that has each carbon atom with it he chain flicked with hydrogen atoms.

Polyunsaturated fatty acid (PUFA)

Fatty acid that has two or more double bonds within the carbon chain.

Unsaturated fatty acid

Fatty acid that is missing hydrogen atoms and has one or more double bones within the carbon chain.

Essential fatty acids

Fatty acids that must be supplied by the diet; linoleic and alpha-linolenic acid are essential fatty acids.

Hydrogenation

Food manufacturing process that adds hydrogen atoms to liquid vegetable oil; forming trans fats.

Fatty acid

Hydrocarbon chain found in lipids; one end of the chain forms a carboxylic acid, and one end forms a methyl group. Fatty acids provide energy for muscles and most other types of cells.

Fat malabsorption

Impaired fat absorption; symptoms include diarrhea, steatorrhea, and rapid weight loss.

Cholesterol

Lipids found in animal foods; precursor for steroid hormones, bile and vitamin D

Monoglyceride

Lipids that has one fatty acid attached to a three carbon compound called glycerol.

Triglyceride

Lipids that has three fatty acids attached to a three-carbon compound called glycerol. Compromise about 95% of lipids in food and in the human body.

Diglyceride

Lipids that has two fatty acids attached to a three carbon compound called glycerol.

Carboxylic acid

Organic molecule with a carboxyl group

Hydrophilic

Part of a molecule that attracts water

Hydrophobic

Part of a molecule that avoids water and attracts lipids.

Oleic acid

18 carbon monounsaturated fatty acid

Alpha-linolenic acid

18 carbon polyunsaturated fatty acid with three double bonds; an essential fatty acid

Linoleic acid

18 carbon polyunsaturated fatty acid with two double bonds; an essential fatty acid

Stearin acid

18 carbon saturated fatty acid

Hydrocarbon chain

Chain of carbon atoms bonded to each other and to hydrogen atoms.

Plant sterols/stanols

Chemicals found in plants that are structurally similar to cholesterol

Bike salts

Component of bile; aid in lipid digestion.

Pancreatic lipase

Digestive enzyme that removes two fatty acids from each triglyceride molecule

Omega or the methyl end

End of a fatty acid containing a methyl group

Lipid digestion and absorption

See page 161

Lipid digestion and absorption

See page 164

Emulsifier

Substance that helps water-soluble and water-insoluble compounds mix with each other

Glycerol

Three carbon alcohol that forms the backbone of fatty acids.

Sterols

Type of lipid that has a more complex chemical structure than triglycerides and phospholipids.

Chylomicron

Type of lipoprotein formed in enterocytes to transport lipids away from GI tract

Omega-3 fatty acid

Type of polyunsaturated fatty acid with the first double bond at the third carbon from the omega end of the molecule.

Omega 6 fatty acid

Type or polyunsaturated fatty acid with the first double bond at the sixth carbon from the omega end of the molecule.

Trans fats

Unsaturated fatty acids that have a trans double bond.

Lipids

class of nutrients that do not dissolve in water; triglycerides, phospholipids l, and sterols. Structural components of the plasma membrane that surrounds each cell.

Phospholipid

type of lipid needed to make cell membranes and for proper functioning of nerve cells; chemically similar to a triglyceride except that one of the fatty acids is replaced by a chemical group that contains phosphorus.