Lipids Flashcards
1
Q
What are lipids
A
Are compounds insoluble in water but soluble in non_polar organic solvents like chloroform, benzene,ether, hot alcohol
2
Q
What are derived lipids
A
They are compounds which are derived from lipids or precursors of lipids e.g fatty acids, steroids
3
Q
Functions of lipids
A
Storage form of energy
Acts as electrical insulator
Act as surfactant, detergent, emulsifying agent
Gives the body shape and contour
Helps to absorb fat soluble vitamins
Structural components of membranes
Improves taste and pal stability of food
Improves insulation against changes in external temperature
4
Q
What are fatty acids
A
It is a group of derived protein
Fatty acids are aliphatic carboxylic acids and have the general formula R_CO_OH
5
Q
What’s the functional group of fatty acids
A
_COOH
6
Q
What is the r group of fatty acid
A
It is the hydrocarbon group
It determines its physical properties
7
Q
General formulae of saturated fatty acid
A
CH3_(CH2)n_COOH
8
Q
Examples of saturated fatty acid
A
Acetic acid
Butyric acid
Palmitic acid
Stearic acid
9
Q
Formula for acetic acid
A
CH3_COOH
10
Q
Butyric acid
A
CH3_(CH2)2_COOH
11
Q
Palmitic acid
A
CH3-(CH2)14_COOH
12
Q
Stearic acid
A
CH3_(CH2)16_COOH
13
Q
Classifications of fatty acids
A
Based on total number of carbon atoms
Even chains
Odd chains
Depending on lenght of hydrocarbon chain
Short chain ( two to 6 carbon atoms)
Medium chain (8 to 14 carbon atoms)
Long chain carbon atoms (16 to 24)
Depending on nature of hydrocarbon
Saturated
Unsaturated which is divided into mono saturated or poly unsaturated
14
Q
Where are odd numbers fatty acid found
A
In milk
In microbial cell walls
15
Q
Importance of acetic and butyric acid
A
Are important metabolic intermediates
16
Q
Components of body fat
A
50% oleic
25% palmitic acid
10% linoleic acid
5% stearic acid
17
Q
Unsaturated fatty acids
A
Are named by adding the suffix enoic after the systematic name
18
Q
When are trans fatty acids formed
A
In the body during metabolism
19
Q
Cis configuration
A
All naturally occurring fatty acids have the cis configuration
Pufa exist in cis configuration in naturally occurring lipids
20
Q
Omega 3 family is what
A
Linolenic acid
21
Q
Omega 6 family is what
A
Linoleic and arachidonic acid
22
Q
Omega 9 family is what
A
Oleic acid
23
Q
Arachidonic acids are precursors of what
A
Prostaglandins
24
Q
Can arachidonic acid be synthesized in the body
A
Yes it can be synthesized, if essential fatty acid are supplied in the diet
25
Where is pentaenoic acid gotten
From fish oil
26
What are ecosanoid
They are derived from 20 carbon arachidonic acid
27
Another name for compound lipid is what
Heterolipid
28
What is the most common component of lipid in the body
Fatty acids
29
When is fatty acid formed freely in the body
During metabolism
30
Suffix of the common saturated fatty acids
Anoic
31
Examples of simple lipid
Triglycerides, triglycerol or neutral fat
Wax
32
Examples of compound lipids
A. Phospholipids containing phosphoric acid
1. Nitrogen containing glycerophosphatides
2. Non nitrogen glycerophosphatides
3. Plasmlogens: having long chain alcohol
4.phosphosphingosine with sphingosine
B. Non phosphorylated lipid
Glycosphingolipid (carbohydrates)
Sulpholipids or sulphatides
33
Examples of derived lipids
Fatty acids
Steroids
Prostaglandin
Leukotrienes
Terpenes
Dolichols
34
Examples of lipid complex to other compounds
Proteolipids
Lipoprotein
35
Suffix of unsaturated fatty acids
Enoic
36
Another name for polyenoic fatty acid is
Polyunsaturated fatty acids
37
Trans fatty acid sources
Are found in diary products and in hydrogenating edible oil
38
Use of trans fatty acid
Although they are considered injurious to health, they are used in food industry to increase the shelf life of the fried food
39
Relationship between pufa and trans fatty acid
Oils containing pufa have high content of tfa
40
Adverse effects of tfa
Effect on plasma lipids and lipoprotein
Causes systemic inflammation
Endothelial dysfunction
Insulin resistance
Diabetes and adiposity
41
Properties of fatty acids
Hydrogenation
Halogenation
Melting point
Salt formation
Ester formation
Oxidation of fatty acids
42
Unsaturated fatty acids can be converted to the corresponding saturated fatty acid by
Hydrogenation of the double bonds
Linolenic _ linoleic_ oleic_ stearic
+2H. +2H. +2H
43
Hydrogenation of oils leads to what
Solidification and saturation e.g vanaspathi
44
Halogenations
When treated with halogens under mild conditions, unsaturated fatty acids can take up two halogen atoms at each double bond to form the halogenated derivative of the fatty acid
E.g oleic acid + I2 =. Di _iodo oleic acid
45
The number of halogens taken up depends on what
Number of double bonds
46
The short and medium chain fatty acids are what
They are liquids
47
Long fatty acids are what
Are solids at 25 degrees
48
Relationship between solubility and lenght chain
Solubility in water decreases with increased lenght chain
49
Relationship between melting and boiling point with increasing chain lenght
Melting and boiling points increases with increasing lenght chain
50
Melting point of unsaturated fatty acid
Unsaturated fatty acids have lower melting point compared to saturated fatty acid of the same chain lenght
51
Saturated and unsaturated fatty acids form salt with what
Alkali
52
What are soaps
Soaps are sodium and potassium salts of long chain fatty acid
53
Which soaps are insoluble
Soaps of magnesium and calcium
54
Which soap is used in grease
Calcium soap
55
What are used as detergents
Alkyl sulphate and alkyl sulphonate , they are not precipitated by hard water
56
Ester formation
Both saturated and unsaturated fatty acids form esters with alcohols especially glycerol
57
Glycerol + fatty acid gives what
Mono acyl glycerol
58
Mono glycerol + fatty acid gives what
Di acyl glycerol
59
Oxidation of fatty acid
Both saturated and unsaturated fatty acids undergo oxidation to give energy
60
How are acids oxidized
Through beta oxidation
61
Unsaturated fatty acids can undergo which type of oxidation
Auto oxidation ,due to its double bond
62
Triglycerides
They are esters of fatty acid with the trihydric alcohol, glycerol
63
Simple triglycerol
When the 3 hydroxyl group of the glycerol is esterified to the same fatty acid
64
Examples of simple triglycerol
Tripalmitin
Triolein
65
Mixed triglycerol
When different fatty acids are esterified to the hydroxyl group of fatty acids . Generally 2 hydroxyl groups is esterified to similar fatty acid and the third one to a different one
66
Pufa is esterified to which carbon atom
The second or beta carbon atom
67
Physical properties of triglycerol
Oils are liquid at 20 degrees
Fats are solids at room temperature
They are hydrophobic and insoluble in water
68
When is hard fatty acid formed
It is formed when fatty acids have a longer chain lenght and are predominantly saturated e.g pig fat
69
When is soft fatty acid formed
They are fatty acids of medium chain triglycerides and are predominantly unsaturated e. g butter and coconut oil
70
Oils
They contain short chain triglycerides and are unsaturated . They are of plant origin
71
Fats
They contain mainly saturated long chain triglycerides
72
Why's triglycerides a good storage form of energy
When stored as triglycerides water is repelled and space requirement is minimal, as excessive fat in the body causes obesity
73
When does hydrolysis of triacylglycerol occur
Digestion of dietary fat
Mobilization of triglycerol from adipose tissue
74
Triglycerides are hydrolysed by what enzymes
Lipase, which are class 3 enzymes(hydrolases)
75
Tri acyl glycerol is hydrolyzed to what
Diacyl glycerol
Mono acyl glycerol
And finally glycerol plus 3 fatty acids
76
What is saponification
Process where triglycerides are hydrolized by alkali
77
Products of saponification
Soaps and glycerol
78
Saponification number
It is the number of milligram of potassium hydroxide needed to saponify one gram of fat
79
Saponification number is an indication of what
Molecular weight of fat , and is inversely proportional to it
80
Saponification number of human fat
194 -198
81
Saponification number of butter
210_230
82
Saponification number of coconut oil
253_262
83
What is iodine number
It is the number of grams of iodine taken up by 100grams of fat
84
What are phospholipids
They contain fatty acid, glycerol with a nitrogenous base
85
What is the simplest phospholipid
Phosphatidates
86
What are phosphatidates
They are the derivatives of phosphatidic acid
87
Composition of phosphatidic acid
It is made up of one glycerol with 2 fatty acids residue esterified to carbon atom one and two. The third hydroxyl group is esterified to phosphoric acid
88
What type of isomerism does phosphatidates exhibit
Optical isomerism,because l_isomer is found in nature
89
Why are phospholipids amphipatic
They have both hydrophilic and hydrophobic portion in their molecule
The glycerol, phosphatic acid and choline constitute the polar head of a phospholipid molecule .
Whereas the hydrocarbon chains of the fatty acid. Constitute the non carbon chain
90
Explain micellar formation
When phospholipids are dispersed in water, it's non polar hydrophobic tail keeps away from water forming a molecular aggregate called micelle
91
Types of liposome
Unilamellar
Multilamellar liposome
92
What are liposomes
A lipid bilayer can close up on itself under appropriate conditions, it is prepared by sonication of mixture of phospholipids and cholesterol
It is a spherical structure
93
Applications of liposomes
In cancer
Chemotherapy
Microbial therapy
Gene therapy
Vaccines
Diagnostic imaging
94
Waxes
They form the secretions of insects, leaves and fruits of plants e.g lanolin or wool fat beeswax, whale sperm oil e.t.c
95
What are waxes
Waxes are esters of higher fatty acids with higher monohydroxy aliphatic alcohols and so have very long straight chains of 60 to 100 carbon atoms.
96
What are phospholipase
They are enzymes that hydrolyzes phospholipids
97
Lecithin when acted upon by phospholipase A2 gives what
Lysolecithin + fatty acids
98
What does phospholipase A2 do to lecithin
It hydrolyzes the fatty acid esterified to the beta / second carbon atom
99
Functions of lysolecithin
It is a detergent and hemolytic agent
100
Where is phospholipase A2 found
In the venom of viper snakes
101
Cholesterol is derived from what Greek words
Chole meaning bile
Steros meaning solid
Ol meaning alcohol
102
What cells can synthesize cholesterol
Almost all nucleated cells
103
Quantity of cholesterol in a 70kg Man
140 gram
104
Color of cholesterol
It is a light yellow crystalline solid, when examined under the microscope they have a notched appearance
105
What is cholesterol soluble in
Chloroform and other fat solvents
106
Most important animal steroid
Cholesterol
107
What organism is cholesterol found in
It is widely distributed in animal tissues
It is absent in prokaryotes, it is absent in plants(plants sterols are present instead)
108
In plants and bacteria , compounds similar to steroids are called
Hopanoids
109
Cholesterol was first isolated from
Bile stones by salle
110
Clinical significance of cholesterol
Atherosclerosis
Myocardial infarction
CVS accidents
Heart attacks
111
Structure of cholesterol
All steroids have cyclopentanoperhydro phenanthrene ring system
112
Describe the ring system of cholesterol
It is a fused ring system made of 3 cyclohexane ring A,B and C
And one cyclopentane ring D.
The 6 membered ring are in a phenanthrene arrangement
113
Carbon atom present in cholesterol
It has 27 carbon atoms
114
Hydroxyl group in cholesterol
It is at the third position
115
Orientation of oH group
It is beta oriented
Projecting above the plane of the ring
116
Double bond in cholesterol
Between C5 and C6 atoms
117
The 8th carbon side chain is beta oriented to
The 17th carbon atom
118
Isomers of cholesterol
Cholestanol (hydrogen atom is alpha oriented)
Coprostanol( hydrogen atom is beta oriented)
119
Beta orientation and alpha orientation
Beta; Always projects above the plane of the ring, is denoted by a straight line
While alpha projects below the plane, always denoted by a dotted line
120
Absorption of cholesterol
Cholesterol ester in the diet is hydrolyzed to cholesterol esterase. The free cholesterol is incorporated into bile salt Michelle Abe absorbed into the mucosal cell.
121
Functions of cholesterol
Cell membrane
Nerve conduction
Bile acids and bile salts
Steroid hormones
Vitamin D
Esterification
122
Excretion of cholesterol
It is excreted through bile
123
Liver and cholesterol
Liver synthesizes cholesterol
Liver removes cholesterol from lipoprotein remnants
Liver is the only organ that can excrete cholesterol through bile
Liver converts cholesterol to bile acids
124
Total plasma lipid
400 to 600 mg/do
40% is cholesterol
30% is phospholipids
20% is triacylglyceride
125
Since lipids are insoluble they combine with what in plasma
Carriers
126
Lipids are complexed with proteins to form
Lipoprotein
127
The protein part of lipoprotein is
Apo lipoprotein
128
Classifications of lipoprotein
Chlyomicrons
Very low density lipoprotein
Intermediate density lipoprotein
Low density lipoprotein
High density lipoprotein
Free fatty acids
129
Apo lipoproteins are synthesized where
In the liver
Small quantities are synthesized in liver
130
Functions of chlyomicrons
They are the transport form of dietary triglycerides, from intestine to the adipose tissue for storage
And to muscle or heart for their energy needs
131
Functions of vldl
Transports triglycerides from liver to peripheral tissues for energy needs
132
Functions of hdl
Transports cholesterol from peripheral tissues to liver
133
Free fatty acids is also known as
Non esterified fatty acid(NEFA)
134
Free fatty acid is complexed with what
Albumin in plasma
135
Functions of bile salt
They facilitate the digestion of lipids
They can form molecular aggregates called mucelle
136
Largest gland in the body
Liver
137
Lipidime
Total lipids in the organism
138
Lipidomics
Study of structure of all members of lipidome, in both health and in diseases
