Lipids

1. LIPIDS

2. What are LIPIDS?
• Lipids are organic compounds formed mainly from alcohol and fatty acids
combined together by ester linkage.
• Lipids are insoluble in water, but soluble in fat or organic solvents (ether,
chloroform, benzene, acetone)
• Lipids include fats, oils, waxes and related compounds. They are widely
distributed in nature both in plants and in animals.
• They have the common property of being
(1) relatively insoluble in water and
(2) Soluble in nonpolar solvents such as ether and chloroform
a compound formed from an alcohol and an acid by removal of water.

3. 1.They are more palatable and storable to unlimited amount
compared to carbohydrates.
2.They have a high-energy value (25% of body needs) and they
provide more energy per gram than carbohydrates and proteins but
carbohydrates are the preferable source of energy.
3.Supply the essential fatty acids that cannot be synthesized by the
body.
Biological Importance of Lipids :
Palatable having a pleasant or agreeable taste

4. 4.Supply the body with fat-soluble vitamins (A, D, E and
K).
5.They are important constituents of the nervous system.
6.Tissue fat is an essential constituent of cell membrane
and nervous system. It is mainly phospholipids in nature
that are not affected by starvation.

5. Following diseases are associated with
abnormal chemistry or metabolism of lipids
• Obesity
• Atherosclerosis
• Diabetes Mellitus
• Hyperlipoproteinemia
• Fatty liver
• Lipid storage diseases
is a general term for hardening of the arteries.
Hyperlipoproteinemia occurs when there is
too much lipid (fat) in the blood.

6. CLASSIFICATION OF LIPIDS
Esters of fatty acids with various alcohols.
a. Fats: Esters of fatty acids with glycerol. Oils are
fats in the liquid state.
b. Waxes: Esters of fatty acids with higher
molecular weight monohydric alcohols.
Simple lipids:
Having but one hydrogen atom in the molecule.

7. a. Phospholipids: Lipids containing, in addition to fatty acids and
an alcohol, a phosphoric acid residue. They frequently have
nitrogen-containing bases and other substituents, .
b. Glycolipids (glycosphingolipids): Lipids containing a fatty acid,
sphing osine, and carbohydrate.
c. Other complex lipids: Lipids such as sulfo lipids and
aminolipids. Lipoproteins may also be placed in this category.
2. Complex lipids : Esters of fatty acids containing groups in
addition to an alcohol and a fatty acid.

8. These include-
• fatty acids
• glycerol
• steroids
• other alcohols
• fatty aldehyde
• ketone bodies
• hydrocarbons, lipid-soluble vitamins, and
hormones.
3) Precursor and derived lipids:

9. a.Steroids
b.Triglycerides
c.Sphingolipids

10. STEROIDS
Definition
Function
Structure
Risks
Types

11. • Steroids are lipids because they are
hydrophobic and insoluble in water,
but they do not resemble lipids
since they have a structure
composed of four fused rings.
• Cholesterol is the most common
steroid and is the precursor to
vitamin D, testosterone, estrogen,
progesterone, aldosterone, cortisol,
and bile salts.
WHAT ARE STEROIDS?
repelling water;
insoluble in water;
not readily
absorbing water.

12. • Steroids are found in the brain and
alter electrical activity in the brain.
• Because they can tone down
receptors that communicate messages
from neurotransmitters, steroids are
often used in anaesthetic medicines.

13. Structure of Steroid Molecules
Unlike phospholipids and fats,
steroids have a fused ring structure.
Although they do not resemble the other
lipids, they are grouped with them because
they are also hydrophobic and insoluble in
water. All steroids have four linked carbon
rings, and many of them, like cholesterol,
have a short tail. Many steroids also have the
–OH functional group, and these steroids are
classified as alcohols called sterols.

14. Steroid hormones include:
• Sex hormones, which influence sex differences and support
reproduction. These include androgens, estrogens, and progestagens.
• The corticosteroids, including most synthetic steroid drugs, with natural
product classes the glucocorticoids (which regulate many aspects of
metabolism and immune function) and the mineralocorticoids (which help
maintain blood volume and control renal excretion of electrolytes)
• Anabolic steroids, natural and synthetic, which interact with androgen
receptors to increase muscle and bone synthesis. In popular use, the term
"steroids" often refers to anabolic steroids.
pertaining to the kidney;

15. Cholesterol
• Cholesterol is the most common steroid and is mainly synthesized in the liver;
• Cholesterol is also a precursor to many important steroid hormones like
estrogen, testosterone, and progesterone, which are secreted by the gonads
and endocrine glands.
• Therefore, steroids play very important roles in the body's reproductive
system. Cholesterol also plays a role in synthesizing the steroid hormones
aldosterone, cortisol, which plays a role in metabolism.

16. • It is a component of the plasma membrane of animal cells and the
phospholipid bilayer.
• Being the outermost structure in animal cells, the plasma membrane is
responsible for the transport of materials and cellular recognition;
• and it is involved in cell-to-cell communication.
• Thus, steroids also play an important role in the structure and function
of membranes.
a thin layer of tissue that
covers a surface, lines a cavity,
or divides a space or organ

18. TRIGLYCERIDES
and fatty acids

19. What are fatty acids?
• a fatty acid is a carboxylic acid with a
long aliphatic chain, which is either
saturated or unsaturated.
• Fatty acids are usually derived from
triglycerides or phospholipids.

20. • A fatty acid is nothing more than a
long C-H chain with a carboxyl group
(COOH) on the end.
• The COOH gives it an acid property.
• The 3….dots represent the chain is
very long.
Structure of fatty acids

21. Fatty acids have many functions in the
body, and play a role in:
Functions of Fatty Acids
• oxygen transport throughout the body.
• providing energy (when glucose, a form of sugar, is
not available)
• development of strong tissues and organs.
• brain functioning.
• lowering cholesterol and reducing risk of heart
disease.
• healthy looking skin.

22. • A triglyceride is an ester derived from
glycerol and three fatty acids
• Triglycerides are the main constituents of
body fat in humans and animals, as well as
vegetable fat.
• They are also present in the blood to
enable the bidirectional transference of
adipose fat and blood glucose from the
liver, and are a major component of
human skin oils.
What are triglycerides?
A sweet viscous fluid
obtained by the
saponification of fats and
fixed oils; used as a solvent,
as a skin emollient, by
injection or in the form of
suppository for constipation,
and as a vehicle and
sweetening agent.
MOVING IN TWO
USUALLY OPPOSITE
DORECTIONSOf, relating to, or
composed of animal
fat; fatty.

23. • There are many different types of triglyceride,
saturated and unsaturated types.
• Saturated fats are "saturated" with hydrogen – all
available places where hydrogen atoms could be
bonded to carbon atoms are occupied. These have a
higher melting point and are more likely to be solid
at room temperature.
• Unsaturated fats have double bonds between some
of the carbon atoms, reducing the number of places
where hydrogen atoms can bond to carbon atoms.
These have a lower melting point and are more
likely to be liquid at room temperature.

24. • Triglycerides are lipids, a type of fat. They
are found in foods that come from both
plants and animals.
• The triglycerides in plants come from
vegetable oils, such as sunflower and
peanut, which remain liquid at room
temperature.
• Meat and dairy products contain
triglycerides in animal fats, which remain
solid at room temperature. Triglycerides are
necessary for certain bodily functions, but
high levels of them can lead to health
problems.

25. • Triglycerides are the most common lipid
found in the body. They contain three chains
of fatty acids.
• Although similar in structure to the
phospholipids that build cell membranes,
triglycerides are completely hydrophobic,
meaning they cannot mix with water, so they
cannot integrate into membranes.
• Because they can't mix with water,
triglycerides bind to specialized proteins
called lipoproteins to enable them to travel
through the blood.

26. FUNCTIONS OF TRIGLYCERIDES
Triglycerides provide your body with
energy, but their main function is to
store energy for later use. The food
you eat contains calories in the form of
carbohydrates, protein and fat. When
you consume more calories than your
body can use, it stores those calories in
the form of triglycerides.

27. STRUCTURES OF
TRIGLYCERIDES
The main molecule that starts the
structure of a triglyceride is glycerol.
Glycerol is a three-carbon molecule with
three hydroxyl groups on them.
These hydroxyl groups are the site of an
ester reaction with three fatty acid
molecules. The fatty acids can be
different types, and the fatty acid
structure defines the type of triglyceride.
The fatty acids are long chains of carbons
with bonded hydrogens.
These are the parts of the triglycerides
that are used for energy production.

28. RISKS OF HIGH TRIGLYCERIDES
• You need some triglycerides for good health.
But high triglycerides might raise your risk of
heart disease and may be a sign of metabolic
syndrome.
• Metabolic syndrome is the combination of high
blood pressure, high blood sugar, too much fat
around the waist, low HDL ("good") cholesterol,
and high triglycerides. Metabolic syndrome
increases your risk for heart disease, diabetes,
and stroke.

29. What causes high triglycerides?
High triglycerides are usually caused by other
conditions, such as:
Obesity.
Poorly controlled diabetes.
An underactive thyroid (hypothyroidism).
Kidney disease.
Regularly eating more calories than you burn.
Drinking a lot of alcohol.

30. A blood test that measures your
cholesterol also measures your
triglycerides. For a general idea about
your triglycerides level, compare your
test results to the following:1
Normal is less than 150.
Borderline-high is 150 to 199.
High is 200 to 499.
Very high is 500 or higher.

32. SPHINGOLIPIDS
• Definition
• Function
• Structures
• RISKS

33. What are Sphingolipids?
• are a class of lipids containing a backbone of
sphingoid bases, a set of aliphatic amino
alcohols that includes sphingosine.
• They were discovered in brain extracts in the
1870s and were named after the
mythological Sphinx because of their
enigmatic nature
• These compounds play important roles in
signal transmission and cell recognition.
or designating a group of organic chemical
compounds in which the carbon atoms are
linked in open chains.

34. • Sphingolipids are named after the spinx in Greek
mythology, part woman and part lion, who
devoured all who could not answer her riddles.
Spingolipids appeared to Johann Thudichum in 1874
as part of the dangerous riddle of the brain.
• Sphingolipids are a second type of lipid found in cell
membranes, particularly nerve cells and brain
tissues. They do not contain glycerol, but retain the
two alcohols with the middle position occupied by
an amine.
• As shown in the graphic on the right, sphingosine
has three parts, a three carbon chain with two
alcohols and amine attached and a long
hydrocarbon chain.
Any of a group of organic compounds of
nitrogen, such as ethylamine, C2H5NH2, that
may be considered ammonia derivatives in
which one or more hydrogen atoms have been
replaced by a hydrocarbon group.

35. STRUCTURE OF SPHINGOLIPIDS
• The long-chain bases, sometimes simply known as sphingoid bases, are the
first non-transient products of de novo sphingolipid synthesis in both yeast
and mammals. These compounds, specifically known as phytosphingosine and
dihydrosphingosine although this term is less common), are mainly C18
compounds, with somewhat lower levels of C20 bases.[3] Ceramides and
glycosphingolipids are N-acyl derivatives of these compounds.[4]
• The sphingosine backbone is O-linked to a (usually) charged head group such
as ethanolamine, serine, or choline.
• The backbone is also amide-linked to an acyl group, such as a fatty acid.

37. TYPES OF SPHINGOLIPIDS
• Simple sphingolipids, which include the
sphingoid bases and ceramides, make up the early
products of the sphingolipid synthetic pathways.
• Sphingoid bases are the fundamental building
blocks of all sphingolipids. The main mammalian
sphingoid bases are dihydrosphingosine and
sphingosine, while dihydrosphingosine and
phytosphingosine are the principle sphingoid bases
in yeast.Sphingosine, dihydrosphingosine, and
phytosphingosine may be phosphorylated.

38. • Ceramides, as a general class, are N-acylated
sphingoid bases lacking additional head groups.
• Dihydroceramide is produced by N-acylation of
dihydrosphingosine. Dihydroceramide is found in both
yeast and mammalian systems.
• Ceramide is produced in mammalian systems by
desaturation of dihydroceramide by dihydroceramide
desaturase 1 (DES1). This highly bioactive molecule
may also be phosphorylated to form ceramide-1-
phosphate.
• Phytoceramide is produced in yeast by hydroxylation
of dihydroceramide at C-4.

39. FUNCTION OF SPHINGOLIPIDS
• Sphingolipids are commonly believed to
protect the cell surface against harmful
environmental factors by forming a
mechanically stable and chemically resistant
outer leaflet of the plasma membrane lipid
bilayer.
• In experimental animals, feeding
sphingolipids inhibits colon carcinogenesis,
reduces (bad) LDL cholesterol and elevates
(good) HDL cholesterol.[24]