LIPIDSORGANIC MOLECULES

LIPIDS INCLUDE FATS AND STEROIDS

CONCEPT (“Exploring Life” pg 98)

Commonly known as fats and oils

Are hydrophobic do not mix with water

Simplest fats are triglycerides

Chain of 3 fatty acids (hydrocarbon molecules) bonded to a glycerol molecule

LIPIDS

TRIGLYCERIDE: SIMPLE LIPID POLYMER (NO MONOMERS IN LIPIDS)

A triglyceride is formed by a glicerol plus 3 fatty acids.

To make a triglyceride:Condensation synthesis reaction= Dehydration reaction

To break a triglyceride: Hydrolysis (lysis=break)

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TRIGLYCERIDE: SIMPLE LIPID

Act as a boundary—they are a major component of cell membranes

Circulate in the body acting as chemical signals to cells—some are hormones

Used to store energy in the body

Act to cushion and insulate the body

FUNCTIONS OF LIPIDS

All the carbon atoms in fatty acid chains contain only single bonds

Include animal fats such as butter

Solids at room temperature

SATURATED FATS

Have at least one double bond between the carbon atoms in one of the fatty acid chains

Found in fruits, vegetables, fish, corn oil, olive oil, and other vegetable oils

Liquids at room temperature

UNSATURATED FATS

FATTY ACIDS STRUCTURE Carboxylic acid group (COOH) Hydrocarbon chain Methyl GROUP (CH3)

Methyl Group

TRIGLYCERIDES

FATTY ACIDS STRUCTURE

Cis: hydorgens of the carbons with the double bond are on the same side of their respective carbons

Trans: Hydrogens of the carbons with the couble bond are on opposite sides of their respective carbons

Unsaturated fatty acids:

CIS

TRANS

FATTY ACIDS STRUCTURE

SATURATED vs. UNSATURATED

Triglyceride structure

Carbon skeleton forms four fused rings

Classified as lipids are hydrophobic

Some act as chemical signals or hormones estrogen and testosterone

Some form structural components of cells cholesterol

STEROIDS

EXAMPLES OF STEROIDS

Essential molecule found in all cell membranes

Serves as base molecule from which other steroids are produced

Has bad reputation cholesterol containing substances in blood are linked to cardiovascular disease

CHOLESTEROL