Билингвальный урок по теме жиры

Lipid = a compound that is insoluble in water, but soluble in an organic solvent (e.g., ether, benzene, acetone, chloroform)

“lipid” is synonymous with “fat”, but also includes phospholipids, sterols, etc.

chemical structure: glycerol + fatty acids

Lipids are a group of naturally occurring molecules that include fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E, and K), monoglycerides, diglycerides, triglycerides, phospholipids, and others.

We already know that lipids are concentrated sources of energy (9.45 kcal/g)

other functions:

1) provide means whereby fat-soluble nutrients (e.g., sterols, vitamins) can be absorbed by the body

2) structural element of cell, subcellular components

3) components of hormones

4) serve a structural function in cells, as sources of energy, and insulation

Lipid Classes

simple: esterified with glycerol

compound: same as simple, but with other compounds also attached

phospholipids: fats containing phosphoric acid and nitrogen (lecithin)

glycolipids: compounded with CHO, but no N

sterols: large molecular with alcohols found in nature and combined fats (e.g., cholesterol)

Saturated vs. Unsaturated Fatty Acids

saturated: have no double bonds between carbons in chain

polyunsaturated(unsaturated): more than one double bond in the chain

most common polyunsaturated fats contain the polyunsaturated fatty acids oleic, linoleic and linolenic acid

unsaturated fats have lower melting points

stearic melts at 70C, oleic at 26C