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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