THIS IS A STUDY GUIDE, NOT AN ALL INCLUSIVE REVIEW.

THERE MIGHT BE THINGS NOT COVERED BY THIS STUDY GUIDE THAT MIGHT BE ASKED IN YOUR QUIZZES and TESTS.

STUDENTS ARE RESPONSIBLE FOR STUDYING THEIR TEXT BOOKS AS PER THE COURSE SYLLABUS

LipidsLESSON # 8

ORGANIC COMPOUNDS

1- Carbohydrates

2- Lipids

3- Proteins

4- Nucleic acids

They are compounds that have carbon as their central element

Lipids are made of the same elements that carbohydrates (carbon, oxygen and hydrogen), but they contain more hydrogen relative to oxygen than do carbohydrates.

6 CARBONS

12 HYDROGENS6 OXYGENS

16 CARBONS2 OXYGENS

32 HYDROGENS

LIPIDS

Fatty Acid

2- Lipids

Lipids are not polymers of simpler components (monomers)

LIPIDS

GENERAL CHARACTERISTICS OF LIPIDS

1- Relatively insoluble in water

2- They are not polymers of simpler units

3- They are not readily break down in water

LIPIDS

LIPIDS

GLYCERIDES

PHOSPHOLIPIDSglycerol

STEROIDS

Different Types of Lipids

They are the most common class of lipids. The molecule of glyceride consists of a head of glycerol and a tail of fatty acids

GLYCERIDES

GLYCERIDES

Different types of GlyceridesGLYCERIDES

DIGLYCERIDESMONOGLYCERIDES TRIGLYCERIDES

A molecule of lipid formed from ONE fatty acid bonded to glycerol

A molecule of lipid formed from TWO fatty acids bonded to glycerol

A molecule of lipid formed from THREE fatty acids bonded to glycerol

R 1R1

R 2

R1

R2R3

Saturated and Unsaturated Fatty Acids

C = CH H

H H1- Saturated fatty acids

2- Unsaturated fatty acids

(Two or more double bound)

GLYCERIDES

They have no double bonds

(One double bound)

Polyunsaturated

Monounsaturated

They have double bonds

b- Oleic acid

GLYCERIDES

Saturated (no double bonds)

Monounsaturated (one double bond)

c- Linoleic acid

a- Palmitic acid

(two double bonds)

Polyunsaturated

Saturated fats are solid at room temperature

Unsaturated fats are liquid at room temperature

H 2Food producers turn naturally occurring oils into fat by saturating them by

bubbling hydrogen trough the oil in a process called hydrogenation.

Hydrogenation produces trans fatty acids

GLYCERIDES

Trans fats increase the concentration of cholesterol in blood. Therefore, they are also harmful for health.

Omega-3-containing fatty acids

Omega-3-containing fatty acids are unsaturated fatty acid, which contain the first double bound in the carbon number 3

Most unsaturated vegetal oils contain the first double bound in the carbon number 6. They are omega-6- containing fatty acids

GLYCERIDES

2 4 6

1 3 5

1 3 4 6

2 5

Fatty Acids and Health

1- Saturated fatty acids are harmful for health because they increase the concentration of cholesterol in blood

2- Trans fats also increase the concentration of cholesterol. Therefore, they are also harmful for health.

3- Monounsaturated and polyunsaturated fats have not negative impact on health.

4- Omega-3-containing fats are beneficial for health because decrease the possibility of heart diseases.

GLYCERIDES

atherosclerosis heart disease.

1- When we eat fat, it is broken down into glycerol and fatty acids that can serve as energy source

2- If the body does not need energy, the glycerol and fatty acids are converted into triglycerides, which are stored in fat cells for later use

GLYCERIDES

Source and Storage of EnergyFunctions of Glycerides

ADIPOSE TISSUE

ADIPOSE TISSUE

GLYCERIDES

Steroids are structurally very different from triglycerides. The central element of steroids are four carbon rings

STEROIDS

STEROIDS

Principal Steroids1- Cholesterol 2- Steroids hormones

STEROIDS

a) Sex Hormones

b) Corticosteroids

cortisolaldosterone

prednisone

Functions of Cholesterol1- Precursor of other steroids (hormones)2- Structural function as part of the outer membrane of all animal cells

STEROIDS

Functions of Steroid HormonesEstrogen and testosterone are important in natural processes as reproduction

Pharmaceutical steroids can be used in potential harmful ways to build muscle mass

They are charged lipid molecules composed of two fatty acids, glycerol, and a phosphate group.

Fatty acid tail:

Phosphate head:

PHOSPHOLIPIDS

glycerol

Hydrophobic

Hydrophilic

PHOSPHOLIPIDS

VARIABLE GROUPPHOSPHATE

GROUP

TRIGLYCERIDE PHOSPHOLIPID

glycerol

PHOSPHOLIPIDS

GLYCEROL GLYCEROL

Functions of Phospholipids1- Structural function on cell membranes. They are the most abundant lipids in cell membranes

PHOSPHOLIPIDS

WAXES

A wax is a lipid composed of a single fatty acid linked to a long-chain alcohol

Functions: Conserve water and protect the plants from outside invaders

Waxy cuticle

Mesophyll cellsEpidermal

cells