This document summarizes key information about cholesterol. It defines cholesterol as an organic molecule derived from Greek terms meaning "bile" and "solid". The document outlines cholesterol's molecular formula, structure, production in vertebrates, functions in the body, and typical daily intake versus synthesis. Cholesterol performs essential functions as a constituent of cell membranes and lipoproteins, and as a precursor for bile salts and steroid hormones. It is required for nerve transmission and formation of the myelin sheath.

1. BIOCHEMISTRY
Presented by : Komal
Zulfiqar

2. CHOLESTEROL

3. Cholesterol, is derived from the
Ancient Greek word Chole - bile and
stereos – solid
Followed by the chemical suffix - ol
for an alcohol, is an organic molecule.
It is a derived lipid molecule – a sterol
or modified steroidIUPAC NAME
(3Β)-CHOLEST-5-EN-3-
OLSystematic name
2,15-dimethyl-14-(1,5- dimethylhexyl)tetracyclo[8.
7.0.02,7.011,15]heptacos-7- en-5-ol

4. PROPERTIES
• Molecular formula C27H46O
• Molar mass 386.65 g/mol
• Appearance: white crystalline powder
• Density 1.052 g/cm3
• Melting point 148–150 °C
• Boiling point 360 °C (decomposes)
• Solubility in water 0.095 mg/L (30 °C)
• Soluble in acetone, benzene, chloroform, ethanol, ether,
hexane, isopropyl myristate, methanol

5. STRUCTURE OF CHOLESTEROL
• The structure of cholesterol consists of four fused rings
(the rings in steroids are denoted by the letters A, B, C,
and D.), With the carbons numbered in the sequence,
and an eight numbered, and branched hydrocarbon
chain attached to the D ring.
• Cholesterol contains two angular methyl groups: the
c-19 methyl group is attached to c-10, and the c-18
methyl group is attached to c-13.
• The c-18 and c-19 methyl groups of cholesterol lie
above the plane containing the four rings

8. PRODUCTION OF CHOLESTEROL IN
VERTEBRATES
• In vertebrates the hepatic cells typically produce greater
amounts of cholesterol than other cells.
• It is almost completely absent among prokaryotes
(bacteria and archaea), although there are some
exceptions such as mycoplasma, which require
cholesterol for growth.

9. BODY CHOLESTEROL CONTENT
• For a man of about 68 kg (150 lb), typical total body-
cholesterol synthesis is approximately 1 g (1,000 mg)
per day,
• Total body content of cholesterol is approximately 35
g, primarily located within the membranes of all the cells
of the body
• . Typical daily dietary intake of additional cholesterol,
is 200–300 mg.

10. INGESTED CHOLESTEROL
• Most ingested cholesterol is esterified, and esterified
cholesterol is poorly absorbed
• . the body also compensates for any absorption of
additional cholesterol by reducing cholesterol synthesis.
• For these reasons, seven to ten hours after ingestion of
cholesterol, blood levels will show little if any effect on
total body cholesterol content or concentrations of
cholesterol in the blood.

11. However, during the first seven hours after
ingestion of cholesterol, the levels significantly
increase
Cholesterol is recycled.
The liver excretes it in a non-esterified form (via
bile) into the digestive tract .
Typically about 50% of the excreted cholesterol is
reabsorbed by the small bowel back into the
bloodstream

12. FUNCTIONS OF
Cholesterol

13. FUNCTION OF CHOLESTEROL
• Cholesterol is the most abundant sterol in humans and
performs a number of essential functions.
• For example it is a major constituent of the plasma
membrane and of plasma lipoproteins.
• It is a precursor of bile salts,
• It is a precursor of steroid hormones that include
adrenocortical hormones, sex hormones, placental hormones
etc. also a precursor of vitamin D, cardiac glycosides, sit sterol
of the plant kingdom, and some alkaloids.
• It is required for the nerve transmission.
• Cholesterol is widely distributed in all cells of the body but
particularly abundant in nervous tissue.

14. Formation of the myelin sheath, a neuron
consisting of fat-containing cells that insulate
the axon from electrical activity.
This ensures proper function of our brains by
aiding route of electrical impulses.
The absence of cholesterol might lead to loss
of memory and difficulty in focusing.
• As a cell to interconnect "lipid molecules",
which are needed to stabilize our cell
membranes.
• As a source of energy
• Maintenance of our body temperature
• Protection of internal organs
• Modulation the fluidity of cell membranes