PHAROS UNIVERSITY FACULTY OF ALLIED MEDICAL SCIENCE

BIOCHEMISTRY 1 (MLBC-201)

Dr. Hewaida FadelDr. Tarek El Sewedy

Department of Medical Laboratory Technology

Faculty of Allied Medical Sciences

Lecture

Lipids and Fatty acids(2)

By the end of this lecture, students will learn:

How to write the chemical formula of

fatty acids.

Classification of fatty acids.

Lipid Nutritional facts.

Intended Learning Outcomes

Lecture Content

• Classification of lipids.

• Nomenclature of fatty acids.

• Classification of fatty acids.

• Fats and diet

Fatty Acids

Fatty acids are hydrocarbon

chains of various lengths

and degrees of unsaturation

that terminate with

carboxylic acid groups.

a. Stearic acid (saturated)

B. Oleic Acid (unsaturated)

1. Classification of lipids

1. Simple

2. Complex

3. Precursor or Derived

Lipids in Cell Membrane (Phospholipds)

1 glycerol + 2 fatty acids + 1 phosphate group + 1 organic functional group = phospholipidPhosphate groups – Interacts with water; because the phosphate head is polar.Fatty acid ‘legs’ – Non-polar, do not interact with water and align themselves together to be protected from the water while exposing the phosphate groups to the water.

C. Derived lipids

• These include lipid-soluble vitamins, and hormones.

Nomenclature of Fatty Acids

• The name for a fatty acid is derived from the name of its parent hydrocarbon by the substitution of oic for the final e. ex. the C18 fatty acid is called octadecanoic acid because the parent hydrocarbon is octadecane (18)

• The notation 18:0 denotes a C18 fatty acid with no double bonds, whereas (18:3n 9,12,15) signifies that there are three double bonds at position 9,12 and 15 of carboxyl carbon.

• Carbon atoms are numbered from the carboxyl carbon (carbon No. 1). The carbon atoms adjacent to the carboxyl carbon (Nos. 2, 3, and 4) are also known as the α, β, and γ carbons, respectively, and the terminal methyl carbon is known as the ω or n-carbon

I-According to number of carbon atoms

Short chain long chain2-10 C atoms >10 C atoms

Butyric acid (4 C) Palmitic acid(16C)

II-According to presence or absence of double bond

Saturated unsaturated

Monounsaturated Polyunsaturated

Palmitic acid, Butyric acid, Caproic acid, Stearic acid

Oleic acid C18Nervonic acid C24

Linoleic acid C18Linolenic acid C18

Arachidonic acid C20

SATURATED FATTY ACIDSCommon

NameCondensed

Formula

Capric CH3(CH2)8COOH

Lauric CH3(CH2)10COOH

Myristic CH3(CH2)12COOH

Palmitic CH3(CH2)14COOH

Stearic CH3(CH2)16COOH

Arachidic CH3(CH2)18COOH

Common Names

RCOOH Formula

# of Double Bonds

Double Bond Position

Palmitoleic C15H29COOH 1 9

Oleic C17H33COOH 1 9

Linoleic C17H33COOH 2 9, 12

Linolenic C17H31COOH 3 9, 12, 15

Arachidonic C19H31COOH 4 5, 8, 11, 14

Common Unsaturated Fatty Acids

Unsaturated fatty acid are classified into

transCis

• Cis and trans are terms that refer to the arrangement of the two hydrogen

atoms bonded to the carbon atoms involved in a double bond. In

the cis arrangement, the hydrogens are on the same side of the double bond.

In the trans arrangement, the hydrogens are on opposite sides of the double

bond

III-According to nutrition state

Essential Non essential

Sarurated FA Monounsaturated FA

Polyunsaturated

Linoleic acid C18

Arachidonic acid C20

1-Non essential fatty acids:

They can be synthesized in the human body

All saturated and monounsaturated FA's

Ex: Palmitoleic acid ( 16:1n;∆9) CH3(CH2)5CH=CH(CH2)7COOH

higher concentrations in the liver

Ex: Oleic acid; ( 18:1n;∆9)

majority of olive oil

Need to get them from diet because the body cannot manufacture them.

2- Essential fatty acids Polyunsaturated fatty acids

Alpha linolenic acid (18:3n;∆9,12,15): is the so-called "parent" fatty acid for

the omega 3 family of fatty acids because the liver can make other omega 3

fatty acids from it.

linoleic acid (LA) (18:2n; ∆9,12);

Is the "parent" fatty acid for the synthesis of other omega 6 fatty acids in the liver. It is

found in the lipids of cell membrane. It is abundant in many vegetable oils, and

sunflower oils.

Arachidonic acid (20;4n;5,8,11,14)

Repair and Growth of skeletal muscle tissue

Abundant fatty acids in the brain

Play a central role in inflammation

Omega-3 fatty acids

• Omega-3 fatty acids (also known as n-3 fatty acids) are polyunsaturated fatty acids

that are essential nutrients for health. We need omega-3 fatty acids for numerous

normal body functions, such as controlling blood clotting and building cell

membranes in the brain, protection against heart disease .

• Our bodies cannot make omega-3 fats, we must get them through food.

• Alpha-linolenic acid (ALA) is the parent compound for Omega 3 fatty acid, is found

in some vegetable oils such as soybean, canola, and in walnuts.

Omega-3 fatty acids•  For good health, we should aim to get at least one rich

source of omega-3 fatty acids in our diet every day. This could be through a serving of fatty fish (such as salmon), a tablespoon of canola or soybean oil in salad dressing or in cooking, or a handful of walnuts.

Omega-6 fatty acids• Omega-6 fatty acids (also known as n-6 fatty acids) are also

polyunsaturated fatty acids that are essential nutrients, meaning that our bodies cannot make them and we must obtain them from food.

• Common dietary sources include safflower, corn, cottonseed, and soybean oils.

• Omega-6 fatty acids lower LDL cholesterol (the "bad" cholesterol) and reduce inflammation, and they are protective against heart disease. So both omega-6 and omega-3 fatty acids are healthy.

Cis and Trans Lipids

• Naturally-occurring unsaturated vegetable oils have almost all cis bonds, but reusing oil for

frying causes some of the cis bonds to convert to trans bonds.

• If oil is used only once like when you fry an egg, only a few of the bonds do this so it’s not too

bad. However, if oil is constantly reused, like in fast food French fry machines, more and more

of the cis bonds are changed to trans until significant numbers of fatty acids with trans bonds

build up.

• Studies showed that fatty acids with trans bonds are carcinogenic and leads to significant

increase in heart disease by increasing levels of bad cholesterol (LDL). The levels of trans

fatty acids in highly-processed (hydrogenated oils), lipid-containing products such as

margarine are quite high.

Cholesterol • Cholesterol is a waxy substance your body uses to protect nerves, make cell tissues

and produce certain hormones.•  A little cholesterol is essential for health.• The liver can manufacture all the cholesterol your body needs.• Low-density lipoprotein (LDL or 'bad') cholesterol can join with fats and other substances to build up

in the inner walls of your arteries. The arteries can become clogged and narrow, and blood flow is

reduced. High-density lipoprotein (HDL or 'good') carries harmful cholesterol away from the arteries

and helps protect you from atherosclerosis, heart attack and stroke.

Atherosclerosis• A type of arteriosclerosis. Atherosclerosis causes arteries to narrow,

weaken and be less flexible. It's the term for the process of fatty build-

up in the inner lining of an artery. The build-up that results is called

plaque and reduces the amount of blood and oxygen that is delivered

to vital organs.

Triglycerides• Triglyceride is a form of fat made in the body. Elevated triglycerides

can be due to overweight/obesity, physical inactivity, cigarette

smoking, excess alcohol consumption and a diet very high in

carbohydrates.

• People with high triglycerides often have a high total cholesterol

level, including a high LDL (bad) level and a low HDL (good) level.

Many people with heart disease and/or diabetes also have high

triglyceride levels.

Fats and diet• Eating low fat food doesn’t mean we should give up fat entirely,

but we do need to educate ourselves about which fats should

ideally be avoided and which ones are more heart-healthy.

• We need fat in our diet. As the most concentrated source of calories (nine calories per gram of fat compared with four calories per gram for protein and carbohydrates), it helps supply energy.

• Fat provides linoleic acid, an essential fatty acid for growth, healthy skin and metabolism.

• It also helps absorb fat-soluble vitamins (A,D,E and K).

• And fat adds flavour and is satisfying, making us feel fuller

Although all fats have the same amount of calories, some are more

harmful than others: saturated fats and trans fats in particular.

Saturated fats• These fats are derived from animal products such as meat, dairy and

eggs. But they are also found in some plant-based sources such as coconut, palm oils. These fats are solid at room temperature. Saturated fats directly raise total and LDL (bad) cholesterol levels. Conventional advice says to Avoid them as much as possible

A meta-analysis published in 2003 found a direct relationship between saturated fat and breast cancer. In 2007, a systematic literature review published by the World Cancer Research Fund and the American Institute for Cancer Research found consistent evidence for a direct relationship between animal fat and colorectal cancer. 

The Ugly fats

Trans Fats or Hydrogenated FatsTrans Fats are typically found in packaged goods and fast food

restaurants They all have/use the ugly fats… TRANS FATS!

The Ugly fat•  scientists discovered that they could create a fat that

would prolong the spoiling of packaged goods by simply adding a hydrogen atom to an unsaturated fat.

• The partially hydrogenated fat creations wouldn’t spoil as easily as non-hydrogenated fats, plus they didn’t break down during temperature changes, which made transporting them easier, and they were less expensive than animal fat.

Another ugly man-made invention!

Trans Fats or Hydrogenated Fats• Are actually unsaturated fats, but they can

raise total and LDL (bad) cholesterol levels while also lowering HDL (good) cholesterol levels.

• Trans fats are used to extend the shelf life of processed foods, typically cookies, cakes, fries and donuts. Any item that contains “hydrogenated oil” or “partially hydrogenated oil” likely contains trans fats.

• Hydrogenation is the chemical process that changes liquid oils into solid fats.

• Since January 2006, all food manufacturers are required to list trans fat content on food labels.

Butter

Margarine, stick

Margarine, tub

Unsaturated fats• Monounsaturated fats and polyunsaturated fats are two types of unsaturated fatty

acids. They are derived from vegetables and plants.

• Monounsaturated fats:• This type of fat is preferable to other types of fat and can be found in olives, olive

oil, nuts, peanut oil, canola oil and avocados. These kinds of fats can lower LDL (bad) cholesterol and maintain HDL (good) cholesterol.

• Polyunsaturated fats:• These are found in sesame, corn, cottonseed and soybean oils. This type of fat has also

been shown to reduce levels of LDL cholesterol, but too much can also lower your HDL cholesterol

Eat Healthy

Stay Healthy

* Students selected for assignmentغالي السيد وجدي محمد هاله

غنيم حسن سعيد هايديالسمان احمد محمود محمد الله هبه

عطية مصطفي متولي هديرمحمود محمد احمد محمود هدير

الله عبد احمد سعد حماده هندحجازي عبده نجاح هند

محمود محمد حسين محمود يمنىعثمان فراج علي محمد حازم

ابراهيم محمد زكريا محمد كاريمانجيد فرج عصام كيرلساحمد حسان صالح محمد

الجوlد آبو العال عبد عاطف محمدسالم ابراهيم محمد نبيل محمد

شوربجي مروان ايمان

بركه محمد علي مصباح ريهاميوسف عسران ربيع سارةياسين عباس زكريا سامح

محمد الباري عبد اللطيف عبد سعيدالمنوفي

الرحمن عبد الاله عبد فارس سليمعاطف مكين مهران محمود سهام

عوض آدم الحميد عبد سوزانفتوح محمد عنتر شاهنده

علي محمد أسامة شروقاحمد سيد السيد السيد محمد الدين صالح

غالياحمد سيد عطيه الكريم عبد محمد صهيب

بغدادي السيد سعيد عاطفخميس علي خميس كمال عاطف

احمد الرؤوف عبد وجيه الله عبدحسين الحافظ عبد حسين عزيزهعسل عطيه محمود محمد عال

بدوي علي السيد عليالبحيصي علي عصام علي

محمد سليم محمد عليداود سليمان سمعان رمسيس عماد

السوسي محمد ابراهيم حسن محمد عمرخلف الله خلف الدين صالح محمد عمرو

يونس الحميد عبد محمد محمد عمرو

ASSIGNMENTS• Selected students are requested to prepare slides about one of the

following topics (To be delivered before next lecture):

• Lipids and disease

• Healthy lipids

• Unhealthy lipids

• Atherosclerosis

• Saturated Fatty acids

• Unsaturated fatty acids

• Triglyceridss

Study Questions

Complete:• -----------,--------------------and------------------are essential fatty acids.• ----------------and --------------are saturated fatty acids.• All --------------and---------------are non essential amino acids.• ----------------------- is the parent compound of glycerophspholipids.• Lipids includes three main classes which are-----,--------and--------

Correct the incorrect word:

1-Essential amino acids are synthesized in human body.

2-Saturated fatty acids have one or more double bonds.

3- Alpha linolenic acid is non-essential amino acid.

4- Palmitoleic acid is essential amino acid.

Study QuestionsComplete:*-----------,--------------------and------------------are essential

fatty acids.*----------------and --------------are saturated fatty acids.*All --------------and---------------are non essential amino

acids.*----------------------- is the parent compound of

glycerophspholipids.*Lipids includes three main classes which are-----,--------

and--------

Correct the incorrect word:

1-Essential amino acids are synthesized in human body.

2-Saturated fatty acids have one or more double bonds.

3- Alpha linolenic acid is non-essential amino acid.

4- Palmitoleic acid is essential amino acid.

Principles of Biochemistry, Donald J. Voet, Judith G. Voet, Charlotte W. pratt; Willey, 3rd ed.

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