Lipid Metabolism: Comprehensive Learning Quizzes for Medical Students

Question 1

Which enzyme catalyzes the initial step of fatty acid oxidation, converting acyl-CoA into enoyl-CoA?

Accepted Answer

Acyl-CoA dehydrogenase

Answer

Thiolase

Answer

Carnitine palmitoyltransferase I (CPT I)

Answer

Malonyl-CoA decarboxylase

Question 2

What is the primary end product of the beta-oxidation cycle?

Accepted Answer

Acetyl-CoA

Answer

NADH

Answer

FADH2

Answer

ATP

Question 3

Which hormone plays a crucial role in promoting lipolysis in adipose tissue, leading to the release of fatty acids?

Accepted Answer

Epinephrine

Answer

Insulin

Answer

Glucagon

Answer

Cortisol

Question 4

Which organ serves as the primary site for de novo fatty acid synthesis in the body?

Accepted Answer

Liver

Answer

Muscle

Answer

Adipose tissue

Answer

Brain

Question 5

Carnitine plays a crucial role in the transport of fatty acids into the mitochondria for oxidation. What is its specific function?

Accepted Answer

Facilitates the transport of long-chain fatty acids across the inner mitochondrial membrane

Answer

Supplies CoA units for the activation of fatty acids

Answer

Dehydrogenates fatty acids, converting them into their unsaturated forms

Answer

Catalyzes the synthesis of malonyl-CoA, a key regulator of fatty acid synthesis

Question 6

Carnitine palmitoyltransferase II (CPT II) deficiency is a type of fatty acid oxidation defect. Which clinical manifestation is commonly associated with this condition?

Accepted Answer

Muscle weakness and exercise intolerance

Answer

Developmental delay and intellectual disability

Answer

Skin rashes and eczema

Answer

Cardiomyopathy and arrhythmias

Question 7

Which lipid class is characterized by a glycerol backbone esterified to three fatty acids?

Accepted Answer

Triglycerides

Answer

Phospholipids

Answer

Steroids

Answer

Sphingolipids

Question 8

High-density lipoprotein (HDL) plays a specific role in cholesterol metabolism. What is its primary function?

Accepted Answer

Transporting cholesterol from peripheral tissues to the liver

Answer

Transporting cholesterol from the liver to peripheral tissues

Answer

Storing cholesterol in the liver

Answer

Synthesizing cholesterol in the liver

Question 9

Which enzyme is responsible for breaking down triacylglycerols into individual fatty acids and glycerol?

Accepted Answer

Lipase

Answer

Phospholipase A2

Answer

Enoyl-CoA reductase

Answer

Thiolase

Question 10

Which of the following is the primary energy source for the heart and brain?

Accepted Answer

Fatty acids

Answer

Glucose

Answer

Ketone bodies

Answer

Amino acids

Question 11

Which metabolic pathway is responsible for fatty acid synthesis from acetyl-CoA?

Accepted Answer

Fatty acid synthase complex

Answer

Glycolysis

Answer

Citric acid cycle

Answer

Gluconeogenesis

Question 12

Which molecule transports fatty acids across the inner mitochondrial membrane?

Accepted Answer

Carnitine

Answer

CoA

Answer

Malate-aspartate shuttle

Answer

Glycerol-3-phosphate

Question 13

Which inherited disorder is characterized by cholesterol accumulation due to a deficiency in the LDL receptor?

Accepted Answer

Familial hypercholesterolemia

Answer

Hyperlipidemia

Answer

Atherosclerosis

Answer

Triglyceridemia

Question 14

Which lipoprotein is responsible for transporting triglycerides from the liver to peripheral tissues?

Accepted Answer

Very low-density lipoproteins (VLDLs)

Answer

Chylomicrons

Answer

Intermediate-density lipoproteins (IDLs)

Answer

Low-density lipoproteins (LDLs)

Question 15

What is the primary function of apolipoprotein A-I in HDL?

Accepted Answer

Promotes cholesterol efflux

Answer

Activates lecithin-cholesterol acyltransferase (LCAT)

Answer

Binds to LDL receptors

Answer

Inhibits lipoprotein lipase

Question 16

Which of the following is a ketone body?

Accepted Answer

Acetoacetate

Answer

Pyruvate

Answer

Lactate

Answer

Succinate

Question 17

What is the primary storage form of lipids in the body?

Accepted Answer

Triglycerides

Answer

Phospholipids

Answer

Cholesterol esters

Answer

Fatty acids

Question 18

Which of the following enzymes is primarily responsible for the initiation of fatty acid oxidation by catalyzing the transfer of fatty acids across the mitochondrial membrane?

Accepted Answer

Carnitine palmitoyltransferase I (CPT-I)

Answer

3-Ketoacyl-CoA thiolase

Answer

Fatty acyl-CoA synthetase

Answer

Acyl-CoA dehydrogenase

Question 19

Which of the following molecules serves as a building block for the synthesis of glycerophospholipids?

Accepted Answer

Choline

Answer

Cholesterol

Answer

Diacylglycerol

Answer

Sphingosine

Question 20

What is the main purpose of lipoproteins in lipid metabolism?

Accepted Answer

Lipid transport

Answer

Energy storage

Answer

Hormone transport

Answer

Immune response

Question 21

Which metabolic pathway is upregulated during extended periods of fasting, leading to the production of ketone bodies?

Accepted Answer

Ketogenesis

Answer

Glycolysis

Answer

Gluconeogenesis

Answer

Fatty acid synthesis

Question 22

What is the primary role of carnitine in the process of fatty acid oxidation?

Accepted Answer

Carrier molecule

Answer

Electron acceptor

Answer

Coenzyme

Answer

Substrate

Question 23

Which of the following statements accurately describes essential fatty acids?

Accepted Answer

Required for normal growth and development, but cannot be synthesized by the body

Answer

Can be synthesized by the body in sufficient quantities

Answer

Present in all types of lipids

Answer

Primarily bound to proteins in blood plasma

Question 24

Which form of lipid serves as the primary energy reserve in the body?

Accepted Answer

Triglycerides

Answer

Cholesterol esters

Answer

Phospholipids

Answer

Glycolipids

Question 25

Which molecule accepts electrons from FADH2 during the electron transport chain in mitochondrial fatty acid oxidation?

Accepted Answer

Ubiquinone

Answer

NADH

Answer

FADH2

Answer

Cytochrome c