cholesterol mcqs

Question 1

What is the primary role of cholesterol in the body?

Answer 1

Crucial component of cell membranes and precursor of steroid hormones and bile acids

Question 2

What is defined as ‘higher risk’ for total blood cholesterol levels?

Answer 2

> 200 mg/dL

Question 3

What health issue is associated with high levels of plasma cholesterol?

Answer 3

Atherosclerosis

Question 4

What is the main precursor for cholesterol biosynthesis?

Answer 4

Acetate

Question 5

List the four stages of cholesterol biosynthesis.

Answer 5

• Synthesis of mevalonate from acetate
• Conversion of mevalonate to two activated isoprenes
• Condensation of six isoprene units to form squalene
• Cyclisation of squalene to the four-ring steroid nucleus

Question 6

What enzyme is responsible for the reduction of HMG-CoA to mevalonate?

Answer 6

HMG-CoA Reductase

Question 7

What does the conversion of mevalonate to isoprene units involve?

Answer 7

Transfer of three phosphate groups from ATP

Question 8

What is the product of the head-to-head condensation of two farnesyl pyrophosphates?

Answer 8

Squalene

Question 9

What is the intermediate formed from squalene during cyclisation?

Answer 9

Lanosterol

Question 10

How is cholesterol primarily exported from the liver?

Answer 10

As biliary cholesterol, bile acids, or cholesteryl esters

Question 11

What is the function of ACAT in cholesterol metabolism?

Answer 11

Esterifies cholesterol for storage and transport

Question 12

What are the main forms of plasma lipoproteins that transport cholesterol?

Answer 12

• Chylomicrons
• LDL
• HDL

Question 13

True or False: There is a positive correlation between LDL levels and arterial disease.

Answer 13

True

Question 14

What is the role of ApoA-1 in cholesterol transport?

Answer 14

Activates LCAT on HDL particles

Question 15

What regulates cholesterol biosynthesis in mammals?

Answer 15

Intracellular cholesterol levels and insulin/glucagon

Question 16

What happens to HMG-CoA reductase when it is phosphorylated?

Answer 16

It becomes inactive

Question 17

What condition results from defective LDL receptors?

Answer 17

Familial hypercholesterolemia

Question 18

What treatment is commonly used to manage high cholesterol levels?

Answer 18

Statins

Question 19

Fill in the blank: Cholesterol is formed from ______ through a series of reactions.

Answer 19

acetyl-CoA

Question 20

What diseases can result from low HDL levels?

Answer 20

• Familial HDL deficiency
• Tangier disease

Question 21

What is the impact of high cholesterol on the LDL receptor gene?

Answer 21

Diminishes transcription, reducing cholesterol uptake

Question 22

How does glucagon affect HMG-CoA reductase activity?

Answer 22

Stimulates phosphorylation, making it inactive

Question 23

What is the consequence of cholesterol accumulation in blood vessels?

Answer 23

Atherosclerosis

Question 24

What role does ApoA-I play in cholesterol metabolism?

Answer 24

role of APoA-1 in cholesterol metabolism activates LCAT on HDL proteins

Question 25

Which hormone activates HMG-CoA reductase by dephosphorylation?

Answer 25

insulin

Question 26

Tangier disease is characterized by:

Answer 26

defective ABCA1 receptors

Question 27

What is the primary function of reverse cholesterol transport?

Answer 27

return excess cholesterol to the liver

Question 28

High intracellular cholesterol levels lead to:

Answer 28

HMG-CoA reductase degradation

Question 29

What is the role of LCAT in cholesterol metabolism?

Answer 29

conversion of cholesterol to cholesteryl esters in HDL

Question 30

What is the primary regulatory mechanism of cholesterol biosynthesis?

Answer 30

Transcriptional control via SREBPs

Question 31

Cholesterol is esterified for storage by which enzyme?

Answer 31

c) ACAT