LIPIDS Flashcards
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1
Q
four major classes of bioorganic substances:
A
*carbohydrates,
*lipids,
*proteins
*nucleic acids.
2
Q
known as ‘fats provide a major way of storing chemical energy and carbon atoms in the body.’
A
Lipids
3
Q
(a lipid) are the basic components of cell
membranes.
A
Phospholipids, glycolipids,
and cholesterol
4
Q
total daily caloric intake of lipid
A
25-45%
5
Q
LIPIDS
A
saturated fatty acid
vitamins
sterols
polyunsaturated fatty acids
trans fatty acid
monounsaturated fatty acids
6
Q
Lipid is an organic compound found in living organisms that is insoluble (or only sparingly soluble)
in water but soluble in nonpolar organic solvents.
A
STRUCTURE AND CLASSICATION OF LIPID
7
Q
divide lipids into five
categories on the basis of lipid function:
A
- Energy-storage lipids (triacylglycerols)
- Membrane lipids (phospholipids, sphingoglycolipids,
and cholesterol) - Emulsification lipids (bile acids)
- Messenger lipids (steroid hormones and eicosanoids)
- Protective-coating lipids (biological waxes)
8
Q
is a naturally occurring monocarboxylic
acid.
A
fatty acid
9
Q
characterization of fatty acid (carbon chain length)
A
long-chain fatty acids (C12 to C26),
medium chain fatty acids (C8 and C10), or short-chain
fatty acids (C4 and C6).
10
Q
classification of fatty acids
A
- saturated fatty acids (SFAs)
- monounsaturated fatty
acids (MUFAs) - polyunsaturated fatty acids (PUFAs).
11
Q
fatty acid with a carbon chain in
which all carbon–carbon bonds are single bonds.
A
saturated fatty
12
Q
a fatty acid with a carbon
chain in which one carbon–carbon double bond is
present.
A
monounsaturated fatty acid
13
Q
MUFAs configuration
A
double bond is nearly always cis.
14
Q
is a fatty acid with a carbon
chain in which two or more carbon–carbon double bonds
are present.
A
polyunsaturated fatty acid
15
Q
Fatty acid family
A
Omega-3
Omega-6
Omega-9
16
Q
Name and structure of Omega-3
A
Alpha-Linoleic acid (ALA) 18:3 (n-3)
Eicosapentanoic acid (EPA) 20:5 (n-3)
Docosahexaenoic acid (DHA) 22:6
(n-3)
17
Q
Name an structure of Omega-6
A
Linoleic acid (LA) 18:2 (n-6)
Gamma-linoleic acid (GLA) 18:3 (n-6)
Arachidonic acid (ARA) 20:4 (n-6)
18
Q
Name and structure of Omega-9
A
Oleic acid (OA) 18:1 (n-9)
19
Q
an unsaturated fatty acid with
its endmost double bond three carbon atoms away from
its methyl end.
A
omega-3 fatty acid
20
Q
an unsaturated fatty acid with
its endmost double bond six carbon atoms away from
its methyl end.
A
omega-6 fatty acid
21
Q
physical properties of fatty acids
A
are largely determined by the length and degree of unsaturation of the fatty acid carbon chain.
22
Q
solubility decreases as carbon
chain length increases.
A
▪Water solubility
23
Q
slight solubility in water.
A
short-chain fatty acids
24
Q
essentially insoluble in water.
A
Long-chain fatty acids
25
is related to the polarity of the carboxyl group present.
slight solubility of short-
chain fatty acids
26
the non-polar nature of the hydrocarbon chain completely dominates solubility considerations.
longer chain fatty acids
27
are strongly **influenced by
both carbon chain length and degree of unsaturation**
(number of double bonds present).
melting points
28
physical properties of fatty acids
As carbon chain
length increases, melting point increases.
29
energy storage in lipids
triacyclglycerols
30
also function
within the body as energy-storage materials.
triacyclglycerols (lipids)
31
triacylglycerols are
concentrated primarily in
special cells (adipocytes)
32
Adipose tissue
containing these cells is found in various parts of the
body:
under the skin, in the abdominal cavity, in the
mammary glands, and around various organs.
33
Triacylglycerols are much more efficient at storing
energy than
**glycogen** (because large quantities of them can be packed into a very small volume.)
34
large quantities of
them can be packed into a very small volume.
large quantities of
them can be packed into a very small volume.
35
a single molecule of glycerol reacts
with three fatty acid molecules;
esterification reaction
producing a triacylglycerol
36
is a lipid
formed by esterification of three fatty acids to a glycerol
molecule.
triacylglycerol/ triglyceride
37
is the portion of a carboxylic acid that remains after the —OH group is removed from the carboxyl
carbon atom.
An acyl group,
38
- is a triacylglycerol mixture that is a solid or a semi-solid at room
temperature (25 ̊C).
- are obtained from animal sources.
- composed largely of triacylglycerols in which
saturated fatty acids predominate
fat
39
- triacylglycerol mixture that is a liquid at room temperature
(25 ̊C).
- are obtained from plant sources.
- contain
triacylglycerols with larger amounts of mono- and
polyunsaturated fatty acids
oil
40
pack closely together thus causing the higher melting points associated with fats.
“linearity”
41
cannot pack as tightly together results is lower melting points.
“bends”
42
A fish would have
some serious problems if its triacylglycerols __________ when it encountered cold water.
“solidified”
43
are colorless, odorless, and
tasteless.
▪Pure fats and pure oils
44
Current dietary fat
recommendations are that people limit their total fat
intake to **30% of total calories**—with up to
- 15% coming
from monounsaturated fat,
- 10% from
- polyunsaturated fat,
- less than 10% from saturated
fats.
45
“bad fat”
saturated fats
46
“good fat”
monounsaturated fats
47
can be both “good fat” and “bad fat.”
polyunsaturated fats
48
fat that can **increase heart disease** risk
saturated fat
49
fat that can decrease both heart disease and breast cancer risk,
monounsaturated fat
50
can reduce heart disease risk but promote the risk of
certain types of cancers
polyunsaturated fat
51
Inuit people take exhibiting a low incidence of heart disease
omega -3 acids
52
U.S. population, which show a correlation
between a high-fat diet and a high incidence of heart
disease.
omega-6 fatty acids
53
are essential fats; have important benefit for your heart, brain and metabolism
omega-3
54
Controls blood clotting; enhances brain and joint function; muscle-building; reduces risk of
cancer, heart disease,
diabetes, inflammation
Fatty fish (salmon, mackerel, cod,
etc.)
Omega-3
55
Regulates brain functioning;
regulate growth and development;
stimulates hair and skin growth;
regulate metabolism; maintains
healthy bones and reproductive
system; increases inflammation
Most vegetable oils, nuts, and
grain-fed meats
Omega-6
56
Reduces inflammation; reduces
insulin resistance,
Produced naturally by the body,
Omega-7
57
Reduces inflammation; improves
joint health and healing; prevents
variety of diseases
can also be found in olive oil
and vegetable oils
Omega-9
58
mackerel omega-3s grams
2.3
59
needed in the human body that must be obtained from dietary sources
essential fatty acid
60
two essential fatty acids:
- Linoleic acid (18:2) - omega-6 acid family
- linolenic acid (18:3) - omega-3 acid family.
61
why essential fatty acids are important?
- needed for proper membrane structure
- starting materials for the production of several nutritionally important longer- chain omega-6 and omega-3 acids.
62
what happens when these 2 are missing (essential acids) from diet
skin reddens and becomes irritated,
infections and dehydration are likely to occur, and the liver may develop abnormalities.
63
has a much higher percentage of the essential fatty acids than cow’s milk.
Human breast milk
64
is the starting material for the biosynthesis of
arachidonic acid.
▪Linoleic acid
65
is the major starting material for
eicosanoids. Helps regulate blood pressure, clotting, and several other important body functions.
▪Arachidonic acid
66
is the starting material for the biosynthesis
of two additional omega-3 fatty acids.
Linolenic acid
67
are important constituents of the
**communication membranes of the
brain and are necessary for normal
brain development.**
are also active in the
retina of the eye.
▪EPA (eicosapentaenoic acid) and
DHA (docosahexaenoic acid)
68
CHEMICAL REACTIONS OF TRIACYLGLYCEROLS
▪Hydrolysis
▪Saponification
▪Hydrogenation
▪Oxidation
69
is the reverse of the esterification
reaction by which it was formed.
**Hydrolysis** of a triacylglycerol
70
Triacylglycerol hydrolysis setting, requires the presence of an
acid or a base.
71
hydrolysis products are
**glycerol and fatty acids.**
acidic conditions,
72
is a reaction carried out in an
alkaline (basic) solution.
▪Saponification
72
the hydrolysis
products are **glycerol and fatty acid salts**
basic conditions,
72
FIGURE OF 1ST STEP
first step is the hydrolysis of the ester linkages to produce glycerol and three fatty acid molecules:
fat or oil + 3H2O → 3 fatty acids + glycerol
72
For fats and oils, the
products of saponification are
glycerol and fatty
acid salts.
73
FIGURE OF 2ND STEP
second step involves a reaction between the fatty
acid molecules and the base (usually NaOH) in the
alkaline solution. This is an acid–base reaction that
produces water plus salts:
3 fatty acids + 3NaOH → 3 fatty acid salts + 3H2O
73
__ of animal fat is the process by which soap was made in pioneer times.
▪Saponification
73
Soap making involved heating
lard (fat) with lye (ashes of wood, an impure form of KOH).
73
soap is prepared by
hydrolyzing fats and oils under high pressure and high temperature.
73
base of the soap
sodium carbonate
73
is a chemical reaction involves hydrogen addition across carbon–carbon multiple bonds, which increases the degree of saturation as some double bonds are converted to single bonds.
Hydrogenation
73
carbon–carbon double bonds present in the fatty acid
residues of a triacylglycerol
**oxidation** with
molecular oxygen (from air) as the oxidizing agent.
73
Two naturally occurring antioxidants
vitamin C and vitamin E.
74
% mass of a cell membrane can
be **lipid materials**; the rest is primarily **protein.**
80%
75
three common
types of membrane lipids:
phospholipids,
sphingoglycolipids, and cholesterol.
76
most abundant type of
membrane lipid.
▪Phospholipids
77
platform molecule on which a
phospholipid is built
the 3-carbon alcohol glycerol
or a more complex C18 aminodialcohol called **sphingosine.**
78
Glycerol-based phospholipids
glycerophospholipids,
79
based on sphingosine
sphingophospholipids
80
lipid that contains two fatty acids and a phosphate group esterified to a glycerol molecule and an
alcohol esterified to the phosphate group.
glycerophospholipid
81
glycerophospholipids have four ester linkages as contrasted to three
ester linkages in
triacylglycerols.
82
have structures based on the 18-carbon
monounsaturated aminodialcohol sphingosine.
Sphingophospholipids
83
is a lipid that contains
both a fatty acid and a carbohydrate component attached to a
sphingosine molecule.
sphingoglycolipid
84
the third of the three major types of membrane lipids,
- is a steroid
▪Cholesterol,
85
Cholesterol’s structure
differs markedly from that of other membrane lipids in that
(1) there are no fatty acid residues present and
(2) neither glycerol nor
sphingosine is present as the platform molecule.
86
is a lipid whose structure is based on a fused- ring system that involves three 6-membered rings and one 5-membered ring.
steroid
87
is a C27 steroid molecule that is a
component of cell membranes and a precursor for
other steroid-based lipids.
▪Cholesterol
88
-ol ending in the name cholesterol
conveys the information that an ____ functional group is present; located on carbon 3 of the steroid nucleus.
alcohol functional group
89
high food cholesterol with 410 mg
liver
90
is a lipid-based structure
that separates a cell’s aqueous-based interior from the
aqueous environment surrounding the cell.
cell membrane
91
is a two-layer-thick structure of
phospholipids and glycolipids with polar heads and non polar tails
lipid bilayer
92
three distinct parts to the bilayer:
- exterior polar “heads,”
- the interior polar “heads,”
- central nonpolar “tails,”
93
the transport process in which a substance moves across a cell membrane by diffusion from a region of **higher concentration to a region of lower concentration** without the cellular energy.
Passive transport
94
few types of molecules that can cross membranes in this manner.
O2, N2, H2O, urea, and ethanol,
95
transport process in which a substance moves across a cell membrane, with the **aid of membrane proteins,**
from a region of higher concentration to a region of lower
concentration **without the expenditure of cellular energy.**
Facilitated transport
96
transport process in which a substance moves across a cell membrane, with the aid of membrane proteins, **against a
concentration gradient with the expenditure of cellular energy.**
Active transport
97
is a substance that can disperse and stabilize water-insoluble substances as colloidal particles in an aqueous solution.
emulsifier
98
Cholesterol derivatives called __ function as emulsifying agents that facilitate the absorption of dietary lipids in the intestine.
bile acids
99
bile acids differ structurally from
cholesterol in three respects:
1. They are **tri- or dihydroxy ** cholesterol derivatives.
2. The carbon **17 side chain** of cholesterol has been oxidized to a
carboxylic acid.
3. The oxidized acid side chain is **bonded to an amino acid**
(either glycine or taurine)through an amide linkage.
100
is a biochemical substance, produced by a
ductless gland, that has a messenger function.
hormone
101
is a hormone that is a cholesterol
derivative.
steroid hormone
102
There are two major classes of steroid hormones:
(1) sex hormones (control
reproduction and secondary sex characteristics)
(2) adrenocorticoid hormones (regulate numerous biochemical processes in the body.)
103
▪The sex hormones can be classified into three major
groups:
1. Estrogens—the female sex hormones
2. Androgens—the male sex hormones
3. Progestins—the pregnancy hormones
104
are synthesized in the **ovaries and adrenal cortex** and are
responsible for the development of female secondary sex
characteristics at the onset of puberty and for regulation of the
menstrual cycle.
Estrogens
105
are synthesized in the **testes and adrenal cortex** and promote the development of secondary male characteristics.
- promote muscle growth
Androgens
106
are synthesized in the **ovaries and the placenta** and prepare the lining of the uterus for implantation of the fertilized ovum.
- They also suppress ovulation
Progestins
107
second major group of steroid hormones consists of the
adrenocorticoid hormones.
108
There are two types of adrenocorticoid hormones.
1. **Mineralocorticoids** control the balance of Na+ and K- ions in
cells and body fluids.
2. **Glucocorticoids** control glucose metabolism and counteract
inflammation.
109
is an oxygenated C20 fatty acid derivative that functions as a messenger lipid.
eicosanoid
110
eicosanoid is derived from the Greek word eikos, which means
“twenty.”
111
The metabolic precursor for most eicosanoids is
arachidonic acid, the 20:4 fatty
acid.
112
The physiological effects of eicosanoids include mediation of
1. The **inflammatory response**, a normal response to tissue damage
2. The production of **pain and fever**
3. The **regulation of blood pressure**
4. The **induction of blood clotting**
5. The control of **reproductive functions**, such as induction of labor
6. The regulation of the **sleep/wake cycle**
113
is a messenger lipid that is a C20-
fatty-acid derivative that contains a cyclopentane ring and oxygen-containing functional groups.
prostaglandin
114
prostaglandins regulatory functions
raising body
temperature, inhibiting the secretion of gastric juices, relaxing and contracting smooth
muscle, directing water and electrolyte balance, etc.
115
reduces inflammation and fever because it inactivates the enzyme needed for prostaglandin synthesis.
Aspirin
116
is a messenger lipid that is a C20-fatty-acid derivative that contains a cyclic ether ring and oxygen-containing functional
groups.
thromboxane
117
important function of thromboxanes
formation of blood clots.
118
Thromboxanes are produced by
blood platelets and promote platelet aggregation.
119
is a messenger lipid that is a
C20-fatty-acid derivative that contains three conjugated double bonds and hydroxy groups.
leukotriene
120
Leukotrienes are found in
leukocytes (white blood cells).
121
is a lipid that is a monoester of a long-chain fatty acid and a
long-chain alcohol.
biological wax
122
Biological waxes are ______ unlike fats and oils, which
are _________
monoesters, triesters.
123
is a pliable, water-repelling substance used particularly in
protecting surfaces and producing polished surfaces.
▪Wax
124
is a particularly hard wax whose uses involve high-
gloss finishes:
Carnauba wax (Brazilian palm tree)
125
mixture of waxes obtained from sheep wool, used as a base for skin creams and ointments intended to
enhance retention of water
Lanolin,
126
is a mixture of long-chain alkanes
obtained from the processing of petroleum.
- also called paraffin
waxes, resist moisture and chemicals and
have no odor or taste.
mineral wax
127
beeswax component
candle wax.
