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LIPIDS. Department of Biochemistry Foundation Module Phase - 1. Lipids. Soluble in non-polar solvents and insoluble in polar solvents. Lipids are not polymers. Serve as vitamins and hormones. Structural components of biological membranes. synthesized bile acids that aid - PowerPoint PPT Presentation
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Department of Biochemistry
Foundation Module Phase - 1
Lipids
Soluble in non-polar solvents and insoluble in polar solvents. Lipids are not polymers
Provide energy
Structural components of biological membranes.
synthesized bile acids that aid
lipid solubilization
Serve as vitamins and hormones.
The lipids of physiological importance for humans have four major functions
What are the health issues associated with lipids?
Classification of lipids
1) Simple lipids-
Give some examples for simple lipids?
2) Complex /Compound lipids-
Fatty acids + Alcohol
Fatty acids + Alcohol+ X
Some common examples for complex lipids
Fatty Acids
Fatty Acids are amphipathic molecules. Why?
What is the chemical difference between saturated and an
unsaturated fatty acid?
Unsaturated fats are preferred over saturated fatty acids for nutritional reasons.
Would you expect a deep sea fish (living in cold water) or a shallow water fish (living in warmer water) to have
a higher percentage of unsaturated fatty acids in its tissues?
(find the best answer)
A deep sea fish A shallow water fish
corn oil contains 86% polyunsaturated fatty acids
So tend to be liquid at room temperature
Saturated fatty acids (tropical oils, animal fats) tend to be solids, or nearly solids, at room temperatures.
Olive oil contains monounsaturated fatty acids. So tend to be liquids at room temperatures, likely to solidify when refrigerated.
The degree of saturation of a fatty acid affects particularly the fatty acid
melting point.
Why does this occur?
Melting Points and Solubility in Water of Fatty Acids
Solubility in H2O
Chain Length
Melting Point
Effects of Double Bonds on the Melting Points
16:0
6016:1 118:0 6318:1 1618:2 -518:3 -11
F. A. M. P. (0C)
M.P.
# Double bonds
What are essential fatty acids?
Name a good source of ‘omega-3 oils’
Oily fish
- salmon, mackerel, sardines,tuna. Pumpkin seeds, sesame seeds soybean oil
Linoleic acid (LA)
It is a component of many commonVegetable oils.
sunflower, soybean, corn and cottonseed oils
Why are essential fatty acids good for you?
I. Saponification Value
. O
C R
O
O
C R
C R
O
H2C O
HC O
H2C O
KOH
H
H
H
H2C O
HC O
H2C O
R C OK+ 3 + 3
What are the main ingredients in your soap?
Soap
• One test tube is filled with Sunflower oil (A). •Coconut oil is placed in a second test tube.(B)• Add few drops of Hubl’s iodine for each solution. • Test tubes are shaken. •After some minutes a spatula full of starch powder is added to each of the two test tubes.
•The test tubes are again shaken.
A B
Comment the observation.
Foods prepared with edible oil develop a kind of smell and undergo changes in taste. What is the reason for this?
Rancidity
Hydrolytic Oxidative
Partial hydrolysis of TAG Oxidation of UFA @double bond positions.
FFA Glycerol
(mono/di) Peroxides
Aldehyde Ketones
Objectionable odour + Taste
Objectionable odour + Taste
Mostly Triacylglycerides:
Fat and oils
O
H2C OH
HC OH
H2C OH
HO C R
HO C R
HO C R
O
O
O
H2C O C RO
O
H2C O C R
HC O C R+ + 3 H2O
Glycerol 3 Fatty Acids Triacylglyceride
What elements are found in lecithin?
What do you know about Sphingolipids?
Identify- a - j
What are Eicosanoids?
leukotrienes phospholipids arachidonate diacylglycerol
prostaglandin H2 prostacyclins thromboxanes
other prostaglandins
Lipoxyganase
PGH2 Synthase
Prostacyclin Synthase
Thromboxane Synthase
Linear pathway
Cyclic pathway B
A
Name the enzymes A& B.
State the mechanisms by which aspirin and ibuprofen inhibit PGH2 Synthesis.
What Is Hydrogenated Vegetable Oil?
Vegetable oils are generally liquid at room temperature, so how is it that we have margarine made from sunflower oil and corn oil?
.
Steroids
•Steroid nucleus
•3 cyclohexane rings
•1 cyclopentane ring
steroid nucleus
Cholesterol
•Most abundant steroid in the body
•Add methyl CH3- groups, alkyl chain, and -OH to steroid nucleus
CH3
HO
CH3
CH3 CH3
CH3
Cholesterol in the Body
•Cellular membranes
•Myelin sheath, brain,
and nerve tissue
•Bile salts
•Hormones
•Vitamin D
Q. Identify each lipid as: (1) phospholipid (2) steroid
(3) triglyceride (4) sphingolipid
A. Cholesterol
B.Glycerol, 2 fatty acids, phosphate, and choline
C.Sphingosine, fatty acid, phosphate, and choline
D.Estradiol
E. Bile salts
F. Most of plasma membranesAnswer
The diagram represents a phospholipid molecule
(c) Name the following parts of the molecule
(i) A
(ii) B
(iii) C
Answers
How Does this happen ???????
Back to the QFor more details
(for your interest only)
a.Fats: Fatty acids + Glycerol
b. Waxes: Fatty acids + Long chain alcohol
Back to the q
Example Fatty acids Alcohol other component
a.Phospholipid
ex:1.Glycero phospholipid
ex: Lecithin
2.Sphingophospho lipid
b.Glycolipids(Glycosphingo lipid)
Fatty acids
Fatty acids
Fatty acids
Fatty acids
Fatty acids
Alcohol
Glycerol
Glycerol
Sphingosine
Sphingosine
Phosphoric acid residue
Phosphoric acid residue
Choline
Phosphoric acid residue
Carbohydrate
Back to the q
O
R C OH
#1 Carbon Acid Group O
R C OH
Non-polar End - Hydrophobic End (Fat-soluble tail)
Polar End - Hydrophilic End
Back to the q
presence of double bonds
CH3 CH2 CH2 CH2 CH2 CH2 CH2 C OH
O1245678 3
CH3 CH2 CH2 CH2 CH2 CH2 CH2 C OH
O1245678 3
Back to the qPresence of double bonds
A deep sea fish
Back to the q
Double bonds place kinks in hydrocarbon chains
and kinked hydrocarbon chains have lower melting points than not kinked
Back to the q
Essential fatty acids (EFAs)
Are fatty acids that are required in the human diet;
They must be obtained from food as human cells have no biochemical pathways capable of producing them internally.
There are two families of EFAs: ω-3 (or omega-3 or n-3) and ω-6 (omega-6, n-6.) I. Alpha-linolenic acid (ALA) -
is a polyunsaturated omega-3 fatty acid.
II. Linoleic acid (LA) is an unsaturated omega-6 fatty acid.
Back to the q
Essential fatty acids are used by every cell in your body -- and healthy cells make healthy people!
EFAs control or modulate an amazing number of cellular processes. Essential fatty acids regulate a large number of mechanisms including increasing the fluidity of cell membranes and improving the ability of selective permeability.
These mechanisms help keep toxins out and bring nutrients into your cells.
Essential fatty acids also influence the activation of cell genes, act as second messengers and produce good eicosanoids.
Eicosanoids help reduce inflammation in the body, help keep blood from clotting, and help keep your blood vessels dilated.
Furthermore, a diet rich in EFAs can be helpful in many diseases
Back to the q
Discussion and background:
Sunflower oil contains unsaturated fatty acids. Iodine adds across the double bonds in an unsaturated bond. Coconut oil consists mainly of glycerides from saturated fatty acids (e.g. palmitic and lauric acid).
Observation: The sample containing Coconut oil turns intensely blue (iodine-starch complex). In Sunflower oil all the iodine will be consumed. Consequently no color change can be observed after the addition of starch.
Back to the q
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a: Oligosaccharide b: Glycoprotein c: Glycolipids d: Head of phospholipid e:Tail of phospholipid f: Phospholipid bilayer g: Filament h:Peripheral protein i: Cholesterol j: Transmembrane protein
Back to the q
Eicosanoids are a family of powerful, hormone-like compounds produced in the body from essential fatty acids . . .
•They have specific effects on target cells close to their site of formation. •They are rapidly degraded, so they are not transported to distal sites within the body.
•Examples: prostaglandins, prostacyclins, thromboxanes, leukotrienes, epoxyeicosatrienoic acids (EETs). •Roles in inflammation, fever, regulation of blood pressure, blood clotting, immune system modulation, control of reproductive processes & tissue growth, sleep/wake cycle regulation.
Back to the q
A: LipoxygenaseB:PGH2 synthase
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Previous slide
A. 2 steroid
B. phospholipid
C. 4 sphingolipid
D. 2 steroid
E. 2 steroid
F. 1 phospholipid
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2 Fatty acidsGlycerolPhosphate group &
N- base
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