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 bondPolyunsaturated: 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