30 Questions
What is the primary function of the LDL receptor?
To transport LDL particles into the cell
What happens to the LDL particle after it is taken into the cell by endocytosis?
It is broken down by lysosomal digestion
What is the result of the lysosomal digestion of the LDL particle?
The release of free cholesterol within the cell
What can the free cholesterol released within the cell be used for?
Both A and B
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
What is familial hypercholesterolaemia (Type IIa hyperlipoproteinaemia)?
Both B and C
What is the consequence of familial hypercholesterolaemia in homozygotes?
They develop extensive atherosclerosis early in life
What is the consequence of familial hypercholesterolaemia in heterozygotes?
They develop extensive atherosclerosis later in life
What is the primary function of cholesterol within the cell?
To be used as a structural component of cell membranes
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
What are the three ketone bodies produced in the body?
Acetoacetate, Beta-hydroxybutyrate, Acetone
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
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
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
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
What is the maximum concentration of fatty acids that can be carried by albumin in the blood?
3 mM
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
What is the primary source of acetone in the body?
Acetone arises from the breakdown of acetoacetate
What is the normal concentration of ketone bodies in the circulation?
Concentrations above 10 mM are considered pathological ketosis
What happens when ketone bodies are present in high concentrations in the plasma?
They can cause acidosis (ketoacidosis)
What is the primary function of lipoproteins in the body?
To transport lipid molecules in the bloodstream
Which of the following is a structural role of apoproteins in lipoproteins?
Packaging non-water soluble lipid molecules into soluble form
Which type of hyperlipoproteinemia is associated with a defective lipoprotein lipase enzyme?
Type I
What is the primary function of the enzyme lecithin:cholesterol acyltransferase (LCAT)?
To convert cholesterol to cholesterol ester
Which type of hyperlipoproteinemia is associated with a defective LDL receptor?
Type IIa
What is the primary function of the enzyme lipoprotein lipase?
To remove core triglycerides from lipoprotein particles
Which type of hyperlipoproteinemia is associated with a defective apoprotein E?
Type III
Which of the following statements about LDL metabolism is correct?
Both a and b are correct
Which of the following is a primary treatment option for hyperlipoproteinemia?
All of the above
Which type of hyperlipoproteinemia is associated with raised chylomicrons and VLDL in fasting plasma?
Type V
This quiz covers the three ketone bodies produced in the body during periods of fasting, starvation, or low food intake: Acetoacetate, Beta-hydroxybutyrate, and Acetone. Learn about their synthesis in the liver from fatty acids and the normal concentration levels in the circulation.
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