Nebal Al - Gallab

Shatha Al - Jabri

10

Mamoon Ahram

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Note: the doctor showed extra examples, they were in the slides, you can refer

to them...

• Naming of Fatty Acids

- 1st Method ( IUPAC system )

We start counting from C (carboxylic carbon/functional group) as number

1.

Ex. If we have a chain of fatty acids that contain 18 C

18 C=8 C+10 C

Octa + deca = OctaDecan (Alkane) +COOH OctaDecanoic Acid Okay. If we have double bond:

Convert OctaDecanoic OctaDecenoic (1 Double bond)

OctaDecaDienoic (2 Double bond)

OctaDecaTrienoic (3 Double bond)

• Designation of Fatty Acid

- Number of Carbon & Bond

18 : 0

18 : 1 “18 Carbons & 1 double bond”

- Location of bonds n

Δ : position of double bond

9 Ex. : cis-Δ : cis double bond between C 9 and 10

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2 Trans-Δ : a Trans double bond between C 2 and 3

*We can also specify double bond ‘’Cis or Trans’’ .

Slides ‘12+13’ in Lipids: important Fatty Acid you should memorize.

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-2nd Method (street way of naming) – Omega System

(ω) : Omega, last letter in Greek alphabet.

We start counting from C (methyl) away from carboxylic group COOH

-Omega 3 means that double bond located between C3 & C4 when we

start from the distal C (Methyl).

*Ex. 18 : 3Δ9,12,15 position of double bonds Omega – 3 ‘Linolenic acid’

Number of C Number of double bonds

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*In omega system, we don’t know number of double bonds & Carbons in the chain

because we don’t talk about single fatty acid; we talk about “Class” of Fatty Acids that

share the position of “First” double bond relative to C-Methyl.

*Derivatives of Fatty Acids

Molecules derived from fatty acids (Linoleic, Arachidonic ...)

-Eicosanoid : Molecules derived from Fatty Acids which contain 20 C atoms OR Class of

molecules derived from Arachidonate (20 C - 4 double bond) , “Eico : 20”

*From Arachidonate, we have 4 types of Eicosanoid:

-LeukoTrienes; refers to leukocytes (immune cells), Tri: 3, ens: double bonds.

-Prostacyclins; its source is from ‘’Prostate gland’’ & looks like Cyclic.

-Prostaglandins; synthesize from ‘’Prostate gland’’ .

-Thromboxanes; high level in blood.

But, Are these molecules found only in these cells?

No, it may found in another type, but the first time they were discovered in these cells.

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They have contradictory functions, that doesn’t mean they stop each other’s functions or

work at the same time, there is homeostasis, it starts as vasodilator then becomes

vasoconstrictor to reach homeostasis.

*Note: Leukotrienes constrict smooth muscles of blood vessels & causes constriction of

bronchus so reduce blood flow & may cause Asthma.

*Aspirin ‘’ Miraculous Molecule’’

Works as inhibitor for Enzyme (Cyclooxygenase) which converts Arachidonic Acid to

prostaglandins.

Recommended to take –baby- Aspirin frequently in small amounts to reduce rate of

heart attack (protection) especially for elderly people.

*Functio ns of Eicosanoid s

Platelet aggregation

Inhibition

prostaglandins

Prostacyclins/ Vasodilator

Activation Thromboxanes

Constriction of Smooth muscles

Thromboxanes

leukotrienes/leads to Asthma

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Why?

Because they found that aspirin targets enzyme called cyclooxygenase; which converts

Arachidonic Acid into prostaglandins, which reduces blood aggregation, so it prevents

blood clotting.

When a doctor describes Aspirin for a patient, he should ask him if he has a problem

in his stomach, why?

Because ‘’Cyclooxygenase’’ is Not a single enzyme, it’s a class of enzymes (COX-1, COX2,)

that is found in different tissues, so the problem is that Aspirin inhibits all types of it.

*Note: COX-1 important in Homeostasis (that’s why it causes problems in stomach)

COX-2 responsible of inflammation

SO... Scientists discover better drug Celebrex inhibits COX-2 only .

*Celebrex act as :

-Antiplatelet

-Anti-inflammatory

Celebrex Reduces temperature , pain BUT when Aspirin went down on the markets in

America , the doctors withdrew it because they believe that Aspirin causes problems for

people who suffer from heart problems but later on, they found that people who already

have problems in their heart shouldn’t take this drug .

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*Notes from lecture :

** Omega-3 which is the Precursor for EPA + DHL is very useful for us; it is involved in

the membrane of neurons in our brain so it Promotes Memory.

-Food that contain Omega-3: Nut, Almonds, Sardine, and Tuna...

**Omega-6 comes from Arachidonic Acid .

**Omega-9 : -Reduces cholesterol; Mediterranean people have lower rate of heart

attack because their food depends mainly on Olive Oil, also Iskimo people have a

good physical structure because it’s food (fish) contains Omega-3 ‘very useful’ .

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Complex Lipids

*You should know for each Fatty Acid it’s Backbone And the structures that connect to it,

For instance TAG : it’s backbone ‘Glycerol’ with 3 Fatty Acids connected to it , stored

mainly in adipose tissue so when your body needs energy, a signal is sent to release Fatty

Acids to blood then to another tissue .

*In TAG, we have Glycerol molecule (3 OH group) + Fatty Acids .

-Reactions between OH and COOH form Ester linkage .

-Simple TAG... 3 ‘Same’ Fatty Acids

-Complex TAG... 3 ‘Mixed’ Fatty Acids

-What’s the importance of the type of F.A that connects to Glycerol?

Promotes physical properties for tri-glyceride itself.

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-shape of saturated F.A >> Chain

-F.A has Cis double bond >> has kink

So when a TG has 3 chains of saturated F.A >>will become Packed> hydrophobic interaction

between them Forms FAT

-Unsaturated F.A (F.A is Cis double bond)>>will become near each other, repulsion happens

>>so the shape of TG differs, so more fluidic form of Oil

**Saponification “soap production”

We separate the F.A from TG by Alkaline hydrolysis >>F.A + Salts become together

>>How does the soap work?

-Carboxyl group (Head) hydrophilic on surface

-Inside the tail which is hydrophobic

>with water. The F.A will be released, tail hate the water so will aggregate each other

forming Micelles.

-Grease + Dirt are Hydrophobic so they become entrapped inside micelles.

**Hydrogenation

Removal of double bond when adding Hydrogen yields Saturated F.A >convert from Oil to

solid F.A. elimination of double bond by hydrogenation.

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- It’s important in industry because it can produce Trans-Fat from Cis bond, forms kink .

*when we have Cis-Fat:

1-If we have complete hydrogenation > will produce saturated F.A (No benefit)

2-If we have partial hydrogenation > will convert the Cis to Trans (appears as saturated) -

Advantages of 2nd way: it’s taste delicious, long sheilf life so it take long time to spoil –

Disadvantage of 2nd way:

a) Our body can’t deal with Trans, Only with Cis, because Trans can’t be digested.

b) Tends to aggregate to form blood clot, so closed blood vessels, so more prone to heart

diseases (Coronary Heart Disease).

It’s used because the half-life of it is longer and it tastes better.

-Margarine

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In margarine, only about two-thirds of the double bonds present in the starting vegetable

oil are hydrogenated, so that the margarine remains soft in the refrigerator and melt on

warm toast.

**Waxes :

-Combination of 2 things (F.A + long chain Alcohol)

-When linked together they form Ester linkage

-Overall it’s Solid

-we can’t Digest Wax > don’t have Enzyme that digest Wax in our body, it has a long half-

life.

**Membrane Lipids

-the most prevalent lipid in membrane is Glycerophospholipid .

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**Phospholipids:

-Simplest type >(Phosphatidic acid- most abundant) /has Glycerol + F.A + phosphate

*instead of phosphate we can put another groups yields to another types.

**Cephalins

-Phosphatidylethanolamine

-Phosphatidylserine

-abundant in brain

*Inositol: sugar molecule, ‘’signalling molecule’’ (sends messages across cell membranes)

*Choline:

Snake venom contain lecithinase, which hydrolyses polyunsaturated fatty acids and

converting lecithin into lysolecithin, eventually cause hemolysis of RBCs .

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**Emulsification

-F.A important in Emulsification which is

important in Industry > Resolving Fatty problem in

the Hydrophilic environment

-When we eat ice-cream, mayonnaise > they contain F.A but incomplete because of

Emulsification.

-Emulsifying agent : is substances that can surround nonpolar molecules and keep them in

suspension in water .

-Because of lecithin’s amphipathic nature, they act as emulsifying agents .

Allah would never place you in a situation

That you can’t handle

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