Cholesterol (from the Ancient Greek chole- (bile) and stereos (solid), followed by the chemical sufffix -ol for an alcohol) is an organic molecule. It is a sterol (or modified steroid), a type of lipid. Cholesterol is biosynthesized by all animal cells and is an essential structural component of animal cell membranes. Cholesterol also serves as a precursor for the biosynthesis of steroid hormones, bile acid and vitamin D. Cholesterol is the principal sterol synthesized by all animals. In vertebrates, hepatic cells typically produce the greatest amounts. It is absent among prokaryotes (bacteria and archaea), although there are some exceptions, such as Mycoplasma, which require cholesterol for growth. cholesterol is essential because it is involved in synthesis of 1. steroidal hormone 2.vitamin-d 3.bile acids 4. it is also structural component of cell membrane IN PLASMA MEMBRANE Cholesterol  is important in the membrane as it helps to maintain cell membrane stability at varying temperatures. Cholesterol is bound to neighbouring phospholipid molecules via hydrogen bonds and therefore at low temperatures, reduces their packing. 2. TRANSPORTATION Cholesteryl ester, a dietary lipid, is an ester of cholesterol. The ester bond is formed between the carboxylate group of a fatty acid and the hydroxyl group of cholesterol. Cholesteryl esters have a lower solubility in water due to their increased hydrophobicity. Esters are formed by replacing at least one –OH (hydroxyl) group with an –O–alkyl (alkoxy) group. They are hydrolyzed by pancreatic enzymes, cholesterol esterase, to produce cholesterol and free fatty acids cholesterol is also important to maintain structure of lipoprotein Cholesterol travels through the blood on proteins called “lipoproteins.” Two types of lipoproteins carry cholesterol throughout the body: 1.LDL (low-density lipoprotein), sometimes called “bad” cholesterol, makes up most of your body's cholesterol. 2.HDL (high-density lipoprotein) called “good cholesterol” makes a less part of your body’s cholesterol

1. CHOLESTEROL
1

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C.M.R COLLEGE OF PHARMACY [C.M.R.C
Made by:-DIVYAM KUMAR SINGH
B.PHARM Ist yr 2nd sem

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Cholesterol (from the Ancient
Greek chole- (bile) and stereos (solid),
followed by the chemical sufffix -ol for
an alcohol) is an organic molecule. It is
a sterol (or modified steroid), a type
of lipid. Cholesterol is biosynthesized by all
animal cells and is an essential structural
component of animal cell membranes.
Cholesterol also serves as a precursor for
the biosynthesis of steroid hormones, bile
acid and vitamin D. Cholesterol is the
principal sterol synthesized by all animals.
In vertebrates, hepatic cells typically
produce the greatest amounts. It is absent
among prokaryotes (bacteria and archaea)
, although there are some exceptions, such
as Mycoplasma, which require cholesterol
for growth.

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FUNCTIONS
OF
CHOLESTEROL
STRUCTURAL
COMPONENT OF
CELL MEMBRANE
TRANSPORT OF
FATTY ACIDS TO LIVERESSENTIAL INGREDIENT IN
LIPOPROTEIN STRUCTURE
PRECURSOR FOR
SYNTHESIS OF
1.STEROID
2.HORMONES
3.VITAMIN D
4.BILE SALTS

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1. STRUCTURAL COMPONENT OF PLASMA MEMBRANE

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Cholesterol is important in the membrane as it helps to
maintain cell membrane stability at varying
temperatures. Cholesterol is bound to neighbouring phospholipid
molecules via hydrogen bonds and therefore at low temperatures,
reduces their packing.

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Cholesteryl ester, a dietary lipid, is an ester of
cholesterol. The ester bond is formed between the
carboxylate group of a fatty acid and the hydroxyl
group of cholesterol. Cholesteryl esters have a
lower solubility in water due to their increased
hydrophobicity. Esters are formed by replacing at
least one –OH (hydroxyl) group with an –O–alkyl
(alkoxy) group. They are hydrolyzed by pancreatic
enzymes, cholesterol esterase, to produce
cholesterol and free fatty acids
TRANSPORT OF FATTY ACID TO LIVER
Cholesteryl ester
Cholesterol

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ESSENTIAL IN STRUCTURE OF LIPOPROTEIN
Cholesterol travels through the blood on proteins called
“lipoproteins.” Two types of lipoproteins carry cholesterol
throughout the body:
1.LDL (low-density lipoprotein), sometimes called “bad”
cholesterol, makes up most of your body's cholesterol.
2.HDL (high-density lipoprotein) called “good cholesterol” makes a
less part of your body’s cholesterol

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SYNTHESIS OF
1. BILE SALTS
2. STEROIDAL HORMONES
3. VITAMIN D
CHOLESTEROL IS NEEDED IN

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CHOLESTEROL TO BILE SALTS
Cholesterol
NADPH+H
NADP
+O2
7^a Hydroxylase
7 hydroxycholesterol
Several steps Several steps
Cholic acid
Glyco-cholic acid * Taurocholic acid*
Deoxycholic acid**
Intestinal bacteria
Chenodeoxylic
acid
Tauro- or glycochenodeoxycholic
Acid*
Litholic acid**
Intestinal bacteria
Taurine or glycine
Taurine
glycine

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NOT REQUIRED FOR EXAM

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NOT
REQUIRED
FOR
EXAMS

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NOT
REQUIRED
FOR
EXAMS

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