Module 3 Lipids (Part 2)

Lipases

Fats and Oils can be hydrolyzed in the presence of an acid, base, or specific enzymes known as ___________

Saponification

The hydrolysis of fats and oils in the presence of a base is used to make soap and is called _______________

Hydrogenation

The ________________ of vegetable oils to produce semi solid fats is an important process in the food industry, Chemically it is essentially identical to the catalytic reaction described for alkenes.

Oxidation

Fats and oils that are in contact with moist air at room temperature eventually undergo ____________ and hydrolysis reactions that cause them to turn rancid, acquiring a characteristic disagreeable odor.

Volatile Fatty Acids

One cause of the odor is the release of ______________ by hydrolysis of the ester bonds.

Hydrolyzable Lipids

These are compounds that can be converted into smaller molecules by hydrolysis, these are compounds that are derived from fatty acids. Examples: Fats, oils, waxes, phospholipids, lipoproteins

Non-hydrolyzable Lipids

These are compounds that cannot be cleaved into smaller molecules by hydrolysis. Examples: Steroids, Prostaglandins, Vitamins, Hormones

Simple Lipids

Esters of fatty acids with various alcohols. Examples: Triglycerides and Waxes

Complex Lipids

Lipids containing parts other than fatty acids and alcohol, found in cell membranes, brain, nervous tissues, myelin sheaths of nerves, and blood platelets. Examples: Phospholipids, Sphingolipids, Glycolipids, and Lipoproteins.

Derived Lipids

These compounds are products of hydrolysis of simple and complex lipids. Examples: Steroids, Prostaglandins, Vitamins, Hormones

Lipids

Are biomolecules that are soluble in organic solvents and insoluble in water, They are not defined by a particular functional group, thus they have a variety of structures and functions.

Lipids

They contain many nonpolar C-C and C-H bonds and few polar bonds resulting in their water insolubility.

Hydrolyzable

__________ lipids can be converted into smaller molecules by hydrolysis.

Nonhydrolyzable

_______________ lipids cannot be cleaved into smaller molecules by aqueous hydrolysis.

Fatty acids

Hydrolyzable lipids are derived from ____________.

Carboxylic acids

Fatty acids are _______________ RCOOH with long C chains of 12-20 atoms

12-20

Fatty acids are carboxylic acids (RCOOH) with long C chains of _____________ C atoms.

Polar portion

Hydrophilic (Head)

Non polar

Hydrophobic (Tails)

Even number

Naturally occurring fatty acids have an _____________ of C atoms.

Saturated fatty acids

Have no double bonds in their long hydrocarbon chains.

Unsaturated fatty acids

Have 1 or more double bonds (generally cis) in their long hydrocarbon chains.

Decreases

As the number of double bonds in the fatty acid increases, the melting point ___________.

71 *C

Stearic acid melting point

16 *C

Oleic acid melting point

Linoleic and Linolenic Acids

Are essential fatty acids, they cannot be produced by the body and must be consumed.

Linoleic acid

Is called an omega-6 acid, because of the position of the first C=C in the nonpolar chain.

Linolenic acid

Is called an omega-3 acid because of the position of the first C=C in the nonpolar chain.

Waxes

Are esters formed from a fatty acid and a high molecular weight alcohol.

Spermaceti Wax

Isolated from the heads of sperm whales

Cetyl Palmitate

Major component of Spermaceti Wax

Hydrophobic

Because of Waxes long nonpolar C chains, waxes are very _____________.

Protective Coatings

Waxes form ____________ on bird’s feathers and sheep’s wool and make up beeswax.

Myricyl Palmitate

Beeswax

Hydrolyzed with water

Like other Esters, Waxes are _______________ in the presence of acid or base to reform the carboxylic acid and alcohol they came from.

Triacylglycerols

Are three esters formed from glycerol and three molecules of fatty acids.

Simple Triacylglycerols

_______________ have three identical fatty acid side chains.

Mixed Triacylglycerols

________________ have two or three different fatty acids.

Saturated Triacylglycerols

________________they make up most animal fat and are solids at room temperature.

Animal fat

Saturated Triacylglycerols contain only saturated fatty acids, they make up most ______________ and are solids at room temperature.

Unsaturated Triacylglycerols

______________ they make up most vegetable oils and are liquids at room temperature.

Monounsaturated Triacylglycerols

Have 1 C=C bond

Polyunsaturated Triacylglycerols

Have many C=C bonds

Decreases

Increasing the number of double bonds in the fatty acid chain _____________ the melting point of the triacylglycerol.