CHOLESTEROL METABOLISM AND RISKS

Question 1

Lipid Profile Reference Range

Answer 1

HDL CHOLESTEROL, LDL CHOLESTEROL, TRIGLYCERIDES, TOTAL CHOLESTEROL

Question 2

is the major sterol in animal tissues.

Answer 2

cholesterol

Question 3

No vegetable oil contains any

Answer 3

cholesterol

Question 4

Only a little portion of the body
cholesterol is derived from.

Answer 4

diet

Question 5

Only a little portion of the body
cholesterol is derived from.

Answer 5

diet

Question 6

bulk of cholesterol is synthesized in the

Answer 6

body

Question 7

Structure of Cholesterol

Answer 7

has the ring called
cyclopentanoperhydrophenanthrene (CPPP)
as a parent structure.

Question 8

Cyclopentano perhydro
phenanthrene ring. has

Answer 8

Total 27 carbon atoms.
One hydroxyl group at the third position.
/ Double bond between carbon atom 5 and 6
/ An 8 carbon side chain at position 17
НО
/ Methyl side chains at positions
10 and 13

Question 9

Cyclopentano perhydro
phenanthrene ring. has

Answer 9

Total 27 carbon atoms.
One hydroxyl group at the third position.
/ Double bond between carbon atom 5 and 6
/ An 8 carbon side chain at position 17
НО
/ Methyl side chains at positions
10 and 13

Question 10

Functions of Cholesterol

Answer 10

Membrane formation, Steroid
Hormones, vitamin d , bile salts ,lipoproteins, cholesteryl esters

Question 11

About blank of cholesterol is synthesized per day in adults.

Answer 11

1 gm

Question 12

Almost all tissues of the body participate in

Answer 12

cholesterol synthesis.

Question 13

Biosynthesis of
cholesterol The largest contribution is made

Answer 13

LIVER (50%),
> INTESTINE (15%),
> SKIN,
> ADRENAL CORTEX,
> REPRODUCTIVE tissues

Question 14

the enzymes involved in the synthesis are found in the blank and blank fractions of the cells.

Answer 14

Cytosol, microsomal

Question 15

provides the carbon atoms in the cholesterol.

Answer 15

Acetyl CoA

Question 16

The reducing equivalents are supplied by blank while blank provides energy.

Answer 16

NADPH, ATP

Question 17

For production of 1 mole of cholesterol

Answer 17

18 moles of Acetyl CoA
• 36 moles of ATP
• 16 moles of NADPH
are required.

Question 18

Steps of the Cholesterol Synthesis

Answer 18

Formation of HMG CoA
Formation of Mevalonate (6C)
Production of Isoprenoid units (5C)
Synthesis of Squalene
Conversion of ….
Squalene to Cholesterol (27C)

Question 19

is the rate limiting enzyme in cholesterol biosynthesis.

Answer 19

HMG-CoA reductase

Question 20

The following are the different kinds of metabolic control:

Answer 20

Feedback Regulation
* Hormonal Regulation
• Nutritional Regulation

Question 21

Inhibition
Competitive inhibitor drugs of HMG-CoA reductase: These are the structural analogues of intermediates in the conversion of HMG-CoA to mevalonate

Answer 21

Pravastatin
Lovastatin
Mevastatin
Simvastatin
Fluvastatin

Question 22

Cholesterol undergo degradative reactions in humans with conversion of cholesterol to physiologically important products like,

Answer 22

Bile acids
& Bile Salts
Steroid Hormones
Vitamin-D

Question 23

Formation of Bile acids
• The primary bile acids are

Answer 23

Cholic acid
• Chenodeoxycholic acid
synthesized in the liver from cholesterol by multistep pathways

Question 24

The primary bile acids are conjugate with glycine and taurine to form

Answer 24

Glycocholicacid
Taurocholic acid
Glycochenodeoxycholic acid
Taurochenodeoxycholic acid

Question 25

The conjugated bile salts are synthesized in

Answer 25

liver

Question 26

• The conjugated bile salts are synthesized in liver and accumulated in the

Answer 26

gallbladder

Question 27

From there they are secreted into the small intestine where they are serve as a emulsifying agents for digestion and absorption of fat

Answer 27

ENTEROHEPATIC Circulation

Question 28

A large portion of the bile salts are reabsorbed and returned to the liver through portal vein. • Thus bile acids are recycled and reused several times in a day. • This is known as

Answer 28

Enterohepatic circulation.

Question 29

is the only route for the excretion of cholesterol from the body.

Answer 29

The fecal excretion of bile salts

Question 30

are responsible for keeping the cholesterol in bile in the soluble state.

Answer 30

Bile salts and phospholipids

Question 31

- Due to their deficiency leads to the accumulation of cholesterol crystals in the gall bladder. This condition is known as

Answer 31

cholelithiasis.

Question 32

Patients with this condition are responds to the administration of the bile acid chenodeoxycholic acid known as

Answer 32

CHENODIOL.

Question 33

Synthesis of Steroid Hormones Cholesterol is the precursor for the synthesis of all the five classes of steroid hormones like;

Answer 33

• Glucocorticoid • Mineralocorticoids • Progesterones • Androgens • Estrogens

Question 34

an intermediate of the biosynthetic pathway of cholesterol, is converted into cholecalciferol by ultra violet rays in the skin.

Answer 34

7-dehydrocholesterol

Question 35

Transport of Cholesterol Cholesterol is present in the plasma lipoproteins in two forms:

Answer 35

70 to 75% are esterified form with long chain fatty acid 2. 25 to 30% are free form this may exchange with different form of lipoproteins.

Question 36

is a plasma enzyme synthesized in liver.

Answer 36

LCAT

Question 37

are the responsible for the transport and elimination of cholesterol from the body.

Answer 37

HDL and the enzyme LCAT

Question 38

LCAT

Answer 38

Cholesterol ,Phosphatidyl choline, Lysophosphatidyl choline, Cholesterol Ester

Question 39

Plasma cholesterol is associated with the different forms of lipoprotein fractions like:

Answer 39

HDL (40 to 60 mg/di) LDL (less than130 mg/dI) VLDL (1/5th of TGL)

Question 40

Friedewald Formula:

Answer 40

LDL = ( Total Cholesterol - (HDL + VLDL)}

Question 41

Major Sources of Liver Cholesterol and its Utilization

Answer 41

Dietary Cholesterol (500mg/day), Bile acids and Bile salts (250mg/day), Synthesis of Cholesterol in Liver (500mg/day), Cholesterol lost in bile (500mg/day), Cholesterol from extra hepatic tissues (Variable), Lipoproteins (variable)

Question 42

HYPERCHOLESTEROLEMIA This condition is associated with the following:

Answer 42

DM Hypothyroidism Obstructive Jaundice Nephrotic syndrome

Question 43

It is also associated with

Answer 43

CHD • ARTHEROSCLEROSIS

Question 44

Control of Hypercholesterolemia

Answer 44

•Consumption of PUFA - Dietary Cholesterol •Dietary fibre • Avoid high Carbohydrate • Impact life style • Moderate alcohol consumption •Uses of drugs

Question 45

HypoCholesterolemia Seen in the following conditions:

Answer 45

Hyperthyroidism • Pernicious Anemia • Malabsorption syndrome • Hemolytic Jaundice

Question 46

It is characterized by intimal lesions called atheromas (also called Atheromatous or atherosclerotic plaques), that protrude into vascular lumina.

Answer 46

Atherosclerosis

Question 47

consists of a raised lesion with a soft, yellow, grumous core of lipid (mainly cholesterol and cholesterol esters) covered by a firm, white fibrous cap. Besides obstructing blood flow, atherosclerotic plaques weaken the underlying media and can themselves rupture, causing acute thrombosis.

Answer 47

Atheromatous plaque

Question 48

a slow and progressive building up of plaque, fatty substances, cholesterol, cellular waste products, calcium and fibrin in the inner lining of

Answer 48

Atherosclerosis or Arteriosclerosis

Question 49

a type of fat normally found in the be bastre make cells, hormones , vitamins helping promote normal growth and development

Answer 49

cholesterol

Question 50

What are the different types of cholesterol in the blood?

Answer 50

• HDL-cholesterol: HDL-C helps the body get rid of excess cholesterol that may otherwise collect in blood vessels. • LDL-cholesterol: Commonly referred to as "bad" cholesterol. It is only when the LDL-C blood level becomes too high that it can cause damage by clogging or blocking blood vessels as you age.

Question 51

are a type of fat found in the blood that provide fuel to help with daily activities, just as a car needs gasoline to function properly. Much of the triglycerides in our bloodstream come from what we eat, although the body also makes triglycerides, especially when we are asleep. When we eat, our body takes the triglycerides it doesn't immediately need and stores them in fat cells to be used later as fuel. While triglycerides are important for your body's normal function, high levels of triglycerides can cause health problems.

Answer 51

Triglycerides

Question 52

This is your overall cholesterol level — the combination of LDL-C, VLDL-C and HDL-C. A high total cholesterol level can increase your risk of cardiovascular disease.

Answer 52

Total cholesterol:

Question 53

This is called the "bad" cholesterol. Too much of it in your blood causes the buildup of fatty deposits (plaques) in your arteries (atherosclerosis), which reduces blood flow. These

Answer 53

•Low-density lipoprotein (LDL) cholesterol.

Question 54

This is called the "good" cholesterol because it helps carry away LDL cholesterol, thus keeping arteries open and your blood flowing more freely.

Answer 54

High-density lipoprotein (HDL) cholesterol.

Question 55

This is a type of cholesterol that's usually present in very low amounts when the blood sample is a fasting samples since it's mostly comes from food you've recently eaten. An increase i type of cholesterol in a fasting sample may be a sign of abnormal lipid metabol

Answer 55

•Very low-density lipoprotein (VLDL) cholesterol:

Question 56

When you eat, your body converts calories it doesn't ne into triglycerides, which are stored in fat cells.

Answer 56

•Triglycerides.

Question 57

High triglyceride levels are associated with several factors,

Answer 57

overweight, eating too many sweets or drinking too much alcohol, smoking being sedentary, or having diabetes with elevated blood sugar levels. cardiovascular disease and pancreatic inflammation.