BIOLOGICALLY IMPORTANT MACROMOLECULES - LIPIDS

LIPIDS Fats Composed of carbon, hydrogen and oxygen -Fewer oxygen, greater carbon and hydrogen Hydrophobic due to increase in C-H bonds and decrease in O-H bonds

LIPIDS FUNCTIONS OF LIPIDS: -Efficient energy storage molecules due to many C-H bonds; provide longer-term energy and processed after carbohydrates are used up -Insulate against heat loss -Protective cushion for organs -Part of cell membranes -Water-repellent coat for fur, feathers and leaves

LIPIDS Monomer: hydrocarbon Formation: hydrocarbons link together to form long chains that can vary in length (~12-24 carbons long)

LIPIDS TYPES OF LIPIDS: -Fatty Acids -Glycerides -Phospholipids -Waxes -Steroids

LIPIDS - FATTY ACIDS Long hydrocarbon chains with a carboxylic acid group at one end May be saturated or unsaturated

LIPIDS – FATTY ACIDS SATURATED FATTY ACIDS -No double bonds between carbon atoms -Naturally more linear -Typically solid at room temperature -Linked to heart disease in humans

LIPIDS – FATTY ACIDS UNSATURATED FATTY ACIDS -At least one double bond between carbon atoms Monounsaturated: one double bond Polyunsaturated: two or more double bonds *** Cannot be synthesized by humans -Naturally have a bend (cis double bonds) which alter the physical properties and behaviour in the body -Generally liquids -Can reduce the risk of heart disease

LIPIDS – FATTY ACIDS

LIPIDS - GLYCERIDE Formed when fatty acids join a glycerol backbone through CONDENSATION/DEHYDRATION SYNTHESIS reactions between the carboxylic acid group of the fatty acid and the hydroxyl group of the glycerol forming an ESTER linkage (ester functional group)

LIPIDS - GLYCERIDE May have monoglycerides, diglycerides or triglycerides

LIPIDS - GLYCERIDE Function: -Most fats we eat -How the body stores fats

LIPIDS – TRIGLYCERIDE HYDROGENATION: chemical addition of hydrogen to unsaturated fatty acids of triglycerides to produce saturated fats - Converts remaining double bonds from cis fats to trans fats

LIPIDS - PHOSPHOLIPIDS Glycerol with two fatty acids and a phosphate group attached to the glycerol backbone - Phosphate is attached to an R group that varies in composition and defines the type of phospholipid

LIPIDS - PHOSPHOLIPIDS When phospholipids interact, they align themselves so that their polar head groups stay together and their nonpolar fatty acid tails stay together Function: form a double layer (bilayer) that forms cell membranes

LIPIDS - WAXES Long chain fatty acids joined to alcohol or carbon rings Solid at room temperature Function: water proof coatings (Ex: on leaves and feathers)

LIPIDS - WAXES Function: -Water proof coatings (Ex: on leaves and feathers) -Various plant functions (Ex: leaf, skin, fur and feathers coating) -Various animal functions (Ex: earwax, beeswax, lanolin, etc.)

LIPIDS - STEROIDS Four fused hydrocarbon rings with several different possible functional groups

LIPIDS - STEROIDS Function: -Cholesterol (adds rigidity to membranes) -Hormones (Ex: testosterone, estrogen, progesterone, adrenaline) -Inflammation treatment -Vitamin D -Can cause heart disease Made by mammals and acquired through diet