ACTIVITY 8 LIPIDS VOCABULARY Lipids Fats Oils Phospholipids

ACTIVITY #8: LIPIDS

VOCABULARY Lipids Fats Oils Phospholipids Triglycerides Steriods Unsaturated fatty acids Saturated fatty acids

LIPIDS Important for energy, cell structure, and waterproof coatings Generally not soluble in water Contain C, H, O (NOT in a 1: 2: 1 ratio ) § Ex: Oleic Acid is C 18 H 34 O 2 Do not have a repeating structural monomer unit § Do not technically form polymers § Different lipids have different structures

TYPES OF LIPIDS 1. Fats- triglycerides: solid at room temperature; usually from animal sources § Examples: butter, shortening, lard 2. Oils- triglycerides: liquid at room temperature; usually from plant sources § Examples: sunflower oil, olive oil, corn oil 3. Waxes: ear wax, beeswax, and the waxy layer on the surface of plant leaves. 4. Steroids: cholesterol; hormones such as testosterone; pigments used in animal vision and in photosynthesis. 5. Phospholipids: important structural component of cell membranes

TRIGLYCERIDES Lipids that form when a glycerol molecule combines with 3 molecules called fatty acids Structure of the fatty acid determines the function of the triglyceride 3 fatty acids Glycerol

SATURATED FATTY ACIDS A fatty acid is SATURATED if each carbon in a lipid’s fatty acid chain is bonded to another carbon atom by a single bond (no C=C double or triple bonds) § tend to form molecules called Saturated fats which are solid at room temperature § contain the maximum amount of hydrogens possible § not very 'heart-healthy'!

UNSATURATED FATTY ACIDS A fatty acid is UNSATURATED if there is at least one carbon double bond § monounsaturated will have 1 double bond A fatty acid is said to be POLYUNSATURATED if there are more than one carbon-carbon double bond § tend to form molecules called oils which are liquid at room temperature § contain fewer hydrogens § more "heart-healthy"!

FORMATION OF TRIGLYCERIDES Fatty acids are attached to the glycerol molecules by dehydration synthesis Occurs at the carboxyl end of each fatty acid § Carboxyl group can be written as COOH or -COOH § Carboxyl group contains a carbonyl (C=O) group and a hydroxyl (–OH) group. Carbonyl Hydroxyl Carboxyl group How many water molecules are removed in the formation of 1 triglyceride? 3

TRIGLYCERIDES Why do you think saturated fats are solid and unsaturated fats are liquids? Think about the structure/layout of each. Saturated Unsaturated

FATTY ACIDS Melting point is the temperature at which a substance melts. § Which one of the fatty acids in the table is saturated? § Which is monounsaturated? § Which are polyunsaturated? § How does the number of double bonds affect the melting point? -5 -11