Slajd 1

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• The schedule of the lecture
• Essential and non-essential fatty acids
• Arachidonic acids and its derivatives
• Triacylglycerols
• Complex lipids
• Glycerophospholipids
• Sphingolipids

2

• Fatty acids
• are carboxylic acids with long chain hydrocarbon
  side groups.
• They are rarely free in nature, but rather occur
  as the major component of the varies lipids.

More in seminars and lab
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• Fatty acids are carbon chains
• of varing length
• short chain (lt6 carbons)
• medium chain (6-10 carbons)
• long chain (12 or more carbons)

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Fatty acid is amphipatic substance
Carboxylic group This is alpha carbon
Methyl group Carbon omega
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Numbering the carbons in a fatty acid
1st carbon
3
17
5
7
9
15
11
13
7
2
4
18
4
10
Carboxylic group
Methyl group
4
2
6
10
12
14
16
8
18
5
7
3
9
1
Alpha carbon
Omega carbon
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Numbering carbons in fatty acid

• There are two possibilities to start counting
  atoms of carbon
• from the carbon at the acid end
• (-COOH),
• from the omega carbon (CH3-end)

Omega is the last letter in the Geek alphabet.
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Chemical describing the unsaturated fatty acids

• An example
• 181c?9 oleic acid
• 183c?9,12,15 linolenic acid

• The number before the colon gives the total
  number of carbons, and
• the number after the colon gives the count of
  double bonds
• The configuration is indicated by c (cis) or t
  (trans)
• The position by double bonds are followed by ?
  and one or more numbers. These numbers denote the
  carbon atom (counting from the carboxyl) where
  each double bond starts.

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Biological type of describing
The location of double bond closed to the omega
(methyl) end of the fatty cid chain identifies a
fatty acids family An example Oleic acid had
the first double bond at carbon 6 (counting from
omega end) and so it is classified as an omega-6
fatty acid.
Omega-3
Omega-6
Omega-9
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Essential and nonessential fatty acids
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Our body can make saturated and omega 9
unsaturated fatty acids. It is not essential to
get them in diet. They are named nonessential
fatty acids.
But our body can not produce double bonds before
9th carbon from the methyl end, so we do not
synthesize certain fatty acids, such as omega-3
(linolenic), omega-6 (linoleic). They must come
from food, so they are called essential fatty
acids!
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• Fatty acids
• are key structural components of
• triglycerides
• and
• phospholipids
• as well as
• they are sometime
• attached to
• cholesterol.

Fatty acid
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Derivatives of arachidonic acid (fatty acid) are
named Eicosanoid compounds.

• They are widely distributed
• in animal tissues,
• produced by virtually all mamalian cells.

C204 Arachidonic acid
CH3(CH2)4(CHCH-CH2)4(CH2)2COOH cis
5,8,11,14-eicosatetraenoic acid
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From arachidonic acid (the eicosanoid acids, C
20) polyunsaturated fatty acid a group of
fatty acids-like substances are
synthesized Eicosanoids They have a wide
variety of effects on body chemistry Generally
they act as mediators of hormone action.
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Arachidonic acid
Eicosanoids
Leukotrienes
Prostaglandins PG
Thomboxanes Tx
PGE2
PGF2
Leukotriene LA4
LB4
TxA2
PGD2
PGI2
LC4
PGH2
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Prostaglandins
two side chain with -COOH in one side chain
cyclopentane ring
-OH group
number of double bonds
16
Thromboxane shows structural resemblance to
PGE2 was originally isolated from thrombocytes
or blood platelets
Stimulate platelets to aggregation in early step
of blood clotting.
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• originally discovered in the class of white
  blood cells and
• were named after the source
• Leukocytes and
• the triene structure
• 3 double bonds
• potent muscle contractant
• that are thought to be involved in the
  pathogenesis of asthma.

Leukotrienes
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Lipids Greek lipos, fat

Lipids body constituents
serve as
Energy stored molecules They produce 9
kcal/g, Whereas sugars 4 kcal/g
Chemical messengers
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• Some lipid properties
• Comparing with nucleic acids and glycans are
  rather small molecules,
• They are not polymers,
• They have a strong tendency to associate through
  noncovalent forces.

More in seminars and lab
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• Lipids
• they are extremely diverse
• and can be divided into groups
• Fats (triacylglycerols) and waxes
• Complex lipids
• Steroids
• Eicosonoids

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LIPIDS
Simple
Complex
G L I C E R O L
Fatty acid
More in seminars and lab
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More in seminars and lab
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Fats accumulated in plant and
animal cells form an oily droplets in
cytoplasm. In animal tissues, in
adipocytes, cells specialized for fat
storage, are almost entire filled by a fat
droplets.
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Sites for fat storage differ for men and
women While men often store excess fat in their
abdomens, women tends to store it in their hips.
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Food fats are mixture of saturated and
unsaturated fatty acids.
Food fats with more unsaturated fatty acids
typically have lower melting points and are more
likely to be liquid in room temperature.
More in seminars and lab
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Fat substitute in food is olestra your
degestive enzymes cannot break it down
Compare
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Fat holds more than just energy. It also
carriers important nutrients, such as fat-soluble
vitamins and carotenoids.
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The schedule of the lecture Complex lipids
1. Phospholipids 1.1.
Glycerophospholipids 1.2.
Sphingophospholipids
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LIPIDS
Simple
Complex Phospholipids
1.2. Sphingophospholipids
1.1.Glycero phospholipids
S F I N G O S I N E
G L I C E R O L
Fatty acid
PO4
PO4
Alcoholx
Alcoholx
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Glycerophospholipids
Glycerol
Fatty acid
Glycerophospholipids are the major components of
biological membranes
Phosphatidic acid
Glycerol- 3-phosphate
X alcohol
Glycerophospholipid
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• Phosphatidylethanolamine is collectively called
  cephalin

ethanolamine
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Choline-containing phosphoglycerides are often
refferred to as lecithin
Choline
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Glycerophospholipids
named according to the identities of the alcohol
-X
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Phospholipids are amphipatic compounds
Hydrophylic polar
Hydrophobic nonpolar
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Phospholipids are the major lipid components of
amphipatic biological membranes, in which they
form lipid bilayer
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Complete hydrolysis of glycerophospholipids
Fatty acids 2 molecule
Glycerol
Phosphate ion
Alcohol Choline or Ethanolamine or Serine
or inositol
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Plasmalogens
are also glycerophospholipids, present mainly in
brain and muscle cell membranes
Fatty acid
Fatty acid aldehyde
Choline
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Phospholipids
Glycerophospholipids
3.5.1.2 Sphingophospholipids

• Ceramide
• Sphingomyelin

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Sphingosine a long chain amino alcohol is a core
structure for sphingolipids
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Ceramide is an acetyl fatty acid derivative of
sphingosine
Ceramide occurs only in small amounts in tissues,
but form the parent compounds of sphingomielins
and sphingoglycolipids
Fatty acid is bound via an amide bond -NH-CO
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Sphingomyelin
Choline
P
Ceramide is esterified by phospho-choline
Fatty acid
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Sphingomyelins are also amphipatic molecules
head
tail
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Phosphoglycerolipids, but not sphingolipids, are
excellent biologic detergents such detergent
action is especially important in the small
intestine, where lipids are emulsified for
digestion purposes.
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The phospholipids as detergents are especially
important in the function of lung, where
lecithin, through its action as a surfactant,
prevents the collapse of its air sacs. The
infant is occasionally born with immature lung
that do not have the appropiate quantity of
lecithin. The clinical result is the respiratory
distress syndrome. It is possible to predict
lung maturity by measuring the lecithin/sphingomye
lin ratio in amniotic fluid.
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Lecithin/sphingomyelin ratio in amniotic
fluid Normal amniotic fluid after 34-36 weeks
of gestation gives an L/S ratio of 21 Lecithin
in mature lung 500 mg/dl
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Thank you! I hope you are not so tired!