5-L2

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What is the primary function of the LDL receptor?

To facilitate the synthesis of cholesterol within the cell

To transport LDL particles into the cell (correct)

To promote the accumulation of cholesterol within the cell

To convert cholesterol esters to free cholesterol

What happens to the LDL particle after it is taken into the cell by endocytosis?

It is broken down by lysosomal digestion (correct)

It increases the synthesis of LDL receptors

It inhibits the synthesis of cholesterol

It is stored as cholesterol esters

What is the result of the lysosomal digestion of the LDL particle?

The inhibition of cholesterol synthesis

The synthesis of new LDL receptors

The conversion of cholesterol to cholesterol esters

The release of free cholesterol within the cell (correct)

What can the free cholesterol released within the cell be used for?

Both A and B Signup and view all the answers

What is the effect of the free cholesterol on the synthesis and exposure of LDL receptors?

It reduces the synthesis and exposure of LDL receptors Signup and view all the answers

What is familial hypercholesterolaemia (Type IIa hyperlipoproteinaemia)?

Both B and C Signup and view all the answers

What is the consequence of familial hypercholesterolaemia in homozygotes?

They develop extensive atherosclerosis early in life Signup and view all the answers

What is the consequence of familial hypercholesterolaemia in heterozygotes?

They develop extensive atherosclerosis later in life Signup and view all the answers

What is the primary function of cholesterol within the cell?

To be used as a structural component of cell membranes Signup and view all the answers

What is the purpose of the mechanism described in the text, involving the LDL receptor and the regulation of cholesterol synthesis?

To prevent the cell from accumulating too much cholesterol Signup and view all the answers

What are the three ketone bodies produced in the body?

Acetoacetate, Beta-hydroxybutyrate, Acetone Signup and view all the answers

Under what conditions are ketone bodies produced in the body?

During periods of low food intake, fasting, starvation, carbohydrate-restrictive diets, and prolonged intensive exercise Signup and view all the answers

Which of the following statements about the properties of ketone bodies is true?

They are water-soluble molecules, and acetoacetate and β-hydroxybutyrate are relatively strong organic acids that may cause acidosis Signup and view all the answers

Which of the following statements about lipid transport is true?

Most of the lipid (around 98%) is carried as highly specialized structures called lipoproteins, while the remaining 2% (mostly fatty acids) are carried bound non-covalently to albumin Signup and view all the answers

What is the primary role of albumin in lipid transport?

To transport fatty acids released from adipose tissue during lipolysis for use as fuel by tissues such as muscle Signup and view all the answers

What is the maximum concentration of fatty acids that can be carried by albumin in the blood?

3 mM Signup and view all the answers

Which of the following statements about the synthesis of ketone bodies is true?

Acetoacetate and β-hydroxybutyrate are synthesized in the liver from acetyl-CoA Signup and view all the answers

What is the primary source of acetone in the body?

Acetone arises from the breakdown of acetoacetate Signup and view all the answers

What is the normal concentration of ketone bodies in the circulation?

Concentrations above 10 mM are considered pathological ketosis Signup and view all the answers

What happens when ketone bodies are present in high concentrations in the plasma?

They can cause acidosis (ketoacidosis) Signup and view all the answers

What is the primary function of lipoproteins in the body?

To transport lipid molecules in the bloodstream Signup and view all the answers

Which of the following is a structural role of apoproteins in lipoproteins?

Packaging non-water soluble lipid molecules into soluble form Signup and view all the answers

Which type of hyperlipoproteinemia is associated with a defective lipoprotein lipase enzyme?

Type I Signup and view all the answers

What is the primary function of the enzyme lecithin:cholesterol acyltransferase (LCAT)?

To convert cholesterol to cholesterol ester Signup and view all the answers

Which type of hyperlipoproteinemia is associated with a defective LDL receptor?

Type IIa Signup and view all the answers

What is the primary function of the enzyme lipoprotein lipase?

To remove core triglycerides from lipoprotein particles Signup and view all the answers

Which type of hyperlipoproteinemia is associated with a defective apoprotein E?

Type III Signup and view all the answers

Which of the following statements about LDL metabolism is correct?

Both a and b are correct Signup and view all the answers

Which of the following is a primary treatment option for hyperlipoproteinemia?

All of the above Signup and view all the answers

Which type of hyperlipoproteinemia is associated with raised chylomicrons and VLDL in fasting plasma?

Type V Signup and view all the answers