LIPIDSLIPIDS

Families of lipids include Families of lipids include fats, fats, phospholipids, and steroids; phospholipids, and steroids; made up mostly of hydrocarbons.made up mostly of hydrocarbons.

These families above These families above

DO NOT mix with waterDO NOT mix with water

LIPIDSLIPIDS Major function is for energy Major function is for energy

and nutrient storage (and nutrient storage (A gram A gram of fat stores more than twice as of fat stores more than twice as much energy as a gram of a much energy as a gram of a polysaccharide.)polysaccharide.) Insulation, protect internal Insulation, protect internal

organs, hormones, used to organs, hormones, used to make up cell membranemake up cell membrane

Fat molecules are made up of four Fat molecules are made up of four parts: parts: • a molecule of a molecule of glycerolglycerol (on the (on the

right) and right) and • three molecules of three molecules of fatty acidsfatty acids..• This structure forms a triglyceride.This structure forms a triglyceride.

Glycerol is a 3 carbon alcoholGlycerol is a 3 carbon alcohol Fatty Acids have LONG carbon Fatty Acids have LONG carbon

skeletons that range in lengthskeletons that range in length

Fatty acidsFatty acids

A hydrocarbon chain with an acidic A hydrocarbon chain with an acidic

––COOH group at one end that attaches COOH group at one end that attaches to the glycerol molecule.to the glycerol molecule.

Since the other unattached end of Since the other unattached end of the fatty acid is –CH, it is a non-polar the fatty acid is –CH, it is a non-polar molecule and will not attract polar molecule and will not attract polar molecules such as water molecules such as water hydrophobichydrophobic

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Saturated FATSSaturated FATS

Have the maximum number of the hydrogen Have the maximum number of the hydrogen atoms at each carbon (no double bonds); atoms at each carbon (no double bonds); as as many hydrogens as possible bonded to the many hydrogens as possible bonded to the carbon skeletoncarbon skeleton

Most fats present in animals ie. Cows, sheepMost fats present in animals ie. Cows, sheep Solid at room temp.Solid at room temp. It contributes to cardiovascular disease since It contributes to cardiovascular disease since

their structure is “saturated”their structure is “saturated”

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Fat continued..Fat continued..

Unsaturated FATSUnsaturated FATS Have one or more DOUBLE BONDS; Have one or more DOUBLE BONDS;

has one or more double bonds and has one or more double bonds and will have a kink in its tail wherever will have a kink in its tail wherever there is a double bond.there is a double bond.

Examples: Plant fatsExamples: Plant fats LiquidLiquid at room temp. at room temp. Fat from plants and fishes are Fat from plants and fishes are

generally unsaturated and are liquid generally unsaturated and are liquid at room temperature – they are oils.at room temperature – they are oils.

Double Bond

PhospholipidsPhospholipids Phospholipids are similar to Phospholipids are similar to

fats, but they only have two fats, but they only have two fatty acids tails. fatty acids tails.

The 3The 3rdrd carbon is attached to a carbon is attached to a phosphate group (water loving)phosphate group (water loving)

When phospholipids are added When phospholipids are added to water, to water, they self assemblethey self assemble

into micelles: a phospholipid into micelles: a phospholipid droplet with the hydrophobicdroplet with the hydrophobic

tails inside and the hydrophilic tails inside and the hydrophilic heads facing the water.heads facing the water.

Heads are hydrophillic (water Heads are hydrophillic (water loving)loving)

Tails are hydrophobic (water Tails are hydrophobic (water hating)hating)

Cell membrane is made of 2 Cell membrane is made of 2 layers of phospholipidslayers of phospholipids

Phospholipid StructurePhospholipid Structure

SteroidsSteroids

Made of a Made of a CARBONCARBON skeleton of skeleton of 4 fused 4 fused ringsrings

CholesterolCholesterol is an is an important steroid for important steroid for the body, in animal the body, in animal cell membranescell membranes

It is the precursor for It is the precursor for the production of other the production of other steroids and steroids and hormoneshormones

SteroidsSteroids BUT a high BUT a high

concentration of concentration of cholesterols causes cholesterols causes ARTHEROSCLERARTHEROSCLEROSIS OSIS which can which can eventually lead to eventually lead to heart attacks!! Oh heart attacks!! Oh No!No!