MCQs on Lipids

Definition, Classification, and Functions of Lipids

1. Which of the following best defines lipids?

A. Water-soluble organic compounds with nitrogen
B. Inorganic compounds with hydrophobic properties
C. Organic compounds insoluble in water but soluble in non-polar solvents
D. Polymers of monosaccharides

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2. Which is an example of a simple lipid?

A. Cholesterol
B. Lecithin
C. Triglyceride
D. Bile salt

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3. Which lipid is a precursor for steroid hormones?

A. Phosphatidylcholine
B. Glycolipid
C. Cholesterol
D. Triglyceride

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4. Derived lipids are obtained from:

A. Enzymatic digestion of proteins
B. Hydrolysis of simple and compound lipids
C. Condensation of amino acids
D. Hydrolysis of carbohydrates

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5. Which of the following lipids is amphipathic and essential in membrane structure?

A. Triglyceride
B. Cholesterol ester
C. Phospholipid
D. Saturated fatty acid

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6. Which is not a function of lipids in the body?

A. Energy storage
B. Enzyme catalysis
C. Cell membrane structure
D. Insulation

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7. Which class of lipids includes fats and oils?

A. Compound lipids
B. Steroids
C. Simple lipids
D. Derived lipids

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8. Which of the following is classified as a compound lipid?

A. Fatty acid
B. Wax
C. Phospholipid
D. Cholesterol

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9. Lipids provide how much energy per gram?

A. 4 kcal
B. 7 kcal
C. 9 kcal
D. 2 kcal

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10. Which lipid acts as a thermal insulator in the human body?

A. Lecithin
B. Triglyceride
C. Cholesterol
D. Ceramide

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✅ Answer Key:

1. C – Lipids are organic compounds insoluble in water but soluble in organic (non-polar) solvents.

2. C – Triglycerides are simple lipids (esters of fatty acids with glycerol).

3. C – Cholesterol is the precursor for all steroid hormones.

4. B – Derived lipids result from hydrolysis of simple or compound lipids.

5. C – Phospholipids have both hydrophobic and hydrophilic regions (amphipathic).

6. B – Enzyme catalysis is a function of proteins, not lipids.

7. C – Simple lipids include fats and oils (e.g., triglycerides).

8. C – Phospholipids are compound lipids containing fatty acids, alcohol, and phosphate.

9. C – Lipids provide 9 kcal/g, the highest among macronutrients.

10. B – Triglycerides stored in adipose tissue provide thermal insulation.

Phospholipids and Their Functions

1. Which of the following is a basic structural component of phospholipids?

A. Glycerol, three fatty acids
B. Glycerol, two fatty acids, phosphate group
C. Glucose and phosphate group
D. Cholesterol and sphingosine

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2. What property makes phospholipids ideal for forming cell membranes?

A. High energy content
B. Amphipathic nature
C. Basic pH
D. Hydrophobic nature only

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3. Which part of the phospholipid molecule is non-polar?

A. Phosphate group
B. Glycerol
C. Fatty acid chains
D. Nitrogen base

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4. Which phospholipid is a major constituent of lung surfactant?

A. Sphingomyelin
B. Phosphatidylethanolamine
C. Dipalmitoylphosphatidylcholine
D. Phosphatidylinositol

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5. Sphingomyelin is classified under:

A. Glycolipids
B. Simple lipids
C. Sphingophospholipids
D. Glycerophospholipids

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6. Which phospholipid is found predominantly in the inner mitochondrial membrane?

A. Lecithin
B. Sphingomyelin
C. Cardiolipin
D. Plasmalogen

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7. Phosphatidylinositol plays a key role in:

A. Hormone synthesis
B. Lipid digestion
C. Cell signaling
D. Protein degradation

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8. Which of the following phospholipids is also known as lecithin?

A. Phosphatidylserine
B. Phosphatidylcholine
C. Sphingomyelin
D. Phosphatidylinositol

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9. Name the phospholipid that is antigenic in nature:

A. Cardiolipin
B. Lecithin
C. Cephalin
D. Sphingomyelin

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10. Which of the following best describes the arrangement of phospholipids in biological membranes?

A. Random dispersion
B. Single layer with hydrophilic tails exposed
C. Bilayer with hydrophobic tails inward
D. Bilayer with hydrophilic tails inward

✅ Answer Key: 

1. B – Glycerol, two fatty acids, phosphate group

2. B – Amphipathic nature

3. C – Fatty acid chains

4. C – Dipalmitoylphosphatidylcholine

5. C – Sphingophospholipids

6. C – Cardiolipin

7. C – Cell signaling

8. B – Phosphatidylcholine

9. A – Cardiolipin

10. C – Bilayer with hydrophobic tails inward

Lipoproteins – Structure, Characteristics, and Functions

1. The core of a lipoprotein molecule contains:

A. Proteins and phospholipids
B. Free cholesterol and apolipoproteins
C. Triglycerides and cholesterol esters
D. Only free fatty acids

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2. Which of the following lipoproteins is richest in triglycerides?

A. HDL
B. LDL
C. VLDL
D. Chylomicrons

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3. Which apolipoprotein is essential for activation of lipoprotein lipase?

A. Apo B-100
B. Apo C-II
C. Apo A-I
D. Apo E

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4. Which lipoprotein is considered “good cholesterol”?

A. LDL
B. HDL
C. VLDL
D. IDL

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5. The major role of LDL is to:

A. Transport triglycerides from intestine to tissues
B. Remove cholesterol from tissues to liver
C. Deliver cholesterol to peripheral tissues
D. Activate lipoprotein lipase

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6. Which lipoprotein has the highest density and protein content?

A. VLDL
B. LDL
C. HDL
D. Chylomicron

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7. Apo B-100 is primarily found in:

A. Chylomicrons only
B. VLDL, IDL, and LDL
C. HDL only
D. All lipoproteins

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8. The enzyme that hydrolyzes triglycerides in chylomicrons and VLDL is:

A. HMG-CoA reductase
B. LCAT
C. Lipoprotein lipase
D. Lecithin

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9. Reverse cholesterol transport is a function of:

A. LDL
B. VLDL
C. HDL
D. Chylomicrons

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10. Which apolipoprotein is responsible for receptor-mediated endocytosis of LDL?

A. Apo C-II
B. Apo A-I
C. Apo B-100
D. Apo E

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✅ Answer Key:

1. C – Triglycerides and cholesterol esters

2. D – Chylomicrons

3. B – Apo C-II

4. B – HDL

5. C – Deliver cholesterol to peripheral tissues

6. C – HDL

7. B – VLDL, IDL, and LDL

8. C – Lipoprotein lipase

9. C – HDL

10. C – Apo B-100

Essential Fatty Acids & Eicosanoids

1. Which of the following is an essential fatty acid?

A. Palmitic acid
B. Stearic acid
C. Linoleic acid
D. Oleic acid

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2. The body cannot synthesize essential fatty acids because it lacks the enzyme to introduce double bonds at which position?

A. Delta-3
B. Delta-6 and Delta-9
C. Delta-9
D. Beyond Delta-9

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3. Deficiency of essential fatty acids may lead to:

A. Hyperglycemia
B. Hair loss and dermatitis
C. Anemia
D. Night blindness

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4. Linoleic acid belongs to which family of fatty acids?

A. Omega-3
B. Omega-6
C. Omega-9
D. Saturated

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5. Which of the following is a function of essential fatty acids?

A. Inhibit protein synthesis
B. Maintain skin integrity and growth
C. Inhibit immune response
D. Act as coenzymes

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6. Which fatty acid is a precursor of eicosanoids?

A. Stearic acid
B. Palmitic acid
C. Arachidonic acid
D. Linolenic acid

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7. Eicosanoids are primarily derived from:

A. Cholesterol
B. Triglycerides
C. Arachidonic acid
D. Glucose

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8. Prostaglandins are classified under which group of lipids?

A. Glycerolipids
B. Steroids
C. Eicosanoids
D. Glycolipids

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9. Which of the following is not a function of prostaglandins?

A. Smooth muscle contraction
B. Regulation of blood pressure
C. Enhancing platelet aggregation
D. Increasing DNA replication

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10. Thromboxane A2 is involved in:

A. Inhibiting platelet aggregation
B. Vasodilation
C. Promoting platelet aggregation and vasoconstriction
D. Lowering heart rate

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✅ Answer Key: Essential Fatty Acids & Eicosanoids

1. C – Linoleic acid

2. D – Beyond Delta-9

3. B – Hair loss and dermatitis

4. B – Omega-6

5. B – Maintain skin integrity and growth

6. C – Arachidonic acid

7. C – Arachidonic acid

8. C – Eicosanoids

9. D – Increasing DNA replication

10. C – Promoting platelet aggregation and vasoconstriction

Digestion and Absorption of Lipids with Disorders

1. The primary site of lipid digestion is:

A. Stomach
B. Small intestine
C. Mouth
D. Large intestine

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2. Which enzyme initiates lipid digestion in the stomach?

A. Pancreatic lipase
B. Gastric lipase
C. Lingual lipase
D. Phospholipase

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3. Pancreatic lipase acts on:

A. Phospholipids only
B. Triglycerides to produce monoglycerides and free fatty acids
C. Cholesterol esters only
D. Proteins

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4. Which of the following is necessary for emulsification of fats?

A. Bile salts
B. Amylase
C. Hydrochloric acid
D. Pepsin

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5. Micelles are formed by:

A. Free fatty acids, monoglycerides, bile salts
B. Proteins and carbohydrates
C. Triglycerides and cholesterol only
D. Pancreatic enzymes

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6. After absorption, long-chain fatty acids are re-esterified into triglycerides inside:

A. Liver cells
B. Enterocytes
C. Adipose tissue
D. Pancreas

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7. Lipids are transported from enterocytes into circulation via:

A. Blood capillaries
B. Lacteals (lymphatic vessels) as chylomicrons
C. Portal vein
D. Hepatic artery

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8. Steatorrhea (fatty stools) indicates a problem in:

A. Lipid digestion or absorption
B. Carbohydrate digestion
C. Protein metabolism
D. Electrolyte balance

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9. Which disorder is characterized by defective bile salt secretion leading to fat malabsorption?

A. Cystic fibrosis
B. Cholestasis
C. Pancreatitis
D. Crohn’s disease

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10. Pancreatic insufficiency results in:

A. Increased lipid absorption
B. Decreased lipid digestion and malabsorption
C. Increased protein digestion
D. Increased bile salt secretion

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✅ Answer Key: Digestion and Absorption of Lipids with Disorders

1. B – Small intestine

2. B – Gastric lipase

3. B – Triglycerides to produce monoglycerides and free fatty acids

4. A – Bile salts

5. A – Free fatty acids, monoglycerides, bile salts

6. B – Enterocytes

7. B – Lacteals (lymphatic vessels) as chylomicrons

8. A – Lipid digestion or absorption

9. B – Cholestasis

10. B – Decreased lipid digestion and malabsorption

 

Beta-Oxidation of Fatty Acids with Disorders

1. Beta-oxidation of fatty acids occurs primarily in:

A. Cytoplasm
B. Mitochondrial matrix
C. Endoplasmic reticulum
D. Golgi apparatus

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2. The first step in beta-oxidation involves:

A. Hydration
B. Oxidation by acyl-CoA dehydrogenase
C. Thiolysis
D. Reduction

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3. What is the product of one cycle of beta-oxidation?

A. One molecule of glucose
B. One molecule of acetyl-CoA, NADH, and FADH2
C. Two molecules of acetyl-CoA
D. One molecule of malonyl-CoA

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4. Which vitamin is a cofactor for the enzyme acyl-CoA dehydrogenase?

A. Vitamin B1
B. Vitamin B2 (riboflavin)
C. Vitamin B6
D. Vitamin B12

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5. Carnitine is essential for:

A. Transport of fatty acids into mitochondria
B. Activation of fatty acids in cytoplasm
C. Beta-oxidation itself
D. Synthesis of fatty acids

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6. Medium-chain acyl-CoA dehydrogenase deficiency (MCADD) leads to:

A. Increased fatty acid oxidation
B. Hypoglycemia and accumulation of fatty acids
C. Increased ketone body production
D. Hyperlipidemia only

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7. In beta-oxidation, fatty acids are shortened by:

A. 3 carbon atoms per cycle
B. 1 carbon atom per cycle
C. 2 carbon atoms per cycle
D. 4 carbon atoms per cycle

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8. Which disorder is caused by a defect in carnitine transport?

A. Zellweger syndrome
B. Primary carnitine deficiency
C. Tay-Sachs disease
D. Gaucher disease

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9. Deficiency of which enzyme results in accumulation of very long-chain fatty acids?

A. Medium-chain acyl-CoA dehydrogenase
B. Very long-chain acyl-CoA dehydrogenase
C. Acetyl-CoA carboxylase
D. Peroxisomal oxidase

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10. Beta-oxidation disorder can result in:

A. Hypoglycemia, muscle weakness, and cardiomyopathy
B. Hyperglycemia and obesity
C. Increased protein synthesis
D. Increased carbohydrate metabolism

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✅ Answer Key: Beta-Oxidation of Fatty Acids with Disorders

1. B – Mitochondrial matrix

2. B – Oxidation by acyl-CoA dehydrogenase

3. B – One molecule of acetyl-CoA, NADH, and FADH2

4. B – Vitamin B2 (riboflavin)

5. A – Transport of fatty acids into mitochondria

6. B – Hypoglycemia and accumulation of fatty acids

7. C – 2 carbon atoms per cycle

8. B – Primary carnitine deficiency

9. D – Peroxisomal oxidase

10. A – Hypoglycemia, muscle weakness, and cardiomyopathy

 

Ketone Bodies Metabolism & Ketosis

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1. Ketone bodies are primarily produced in the:

A. Liver mitochondria
B. Cytoplasm of muscle cells
C. Adipose tissue
D. Pancreas

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2. The main ketone bodies produced during ketogenesis are:

A. Acetate, citrate, and malate
B. Acetoacetate, beta-hydroxybutyrate, and acetone
C. Pyruvate and lactate
D. Glucose and fructose

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3. The rate-limiting enzyme of ketogenesis is:

A. HMG-CoA synthase
B. HMG-CoA lyase
C. Acetyl-CoA carboxylase
D. Lipoprotein lipase

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4. Ketone bodies are used as an energy source primarily by:

A. Liver and adipose tissue
B. Brain, heart, and skeletal muscles
C. Red blood cells
D. Pancreas

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5. During prolonged fasting, ketone bodies:

A. Increase in blood to provide alternative energy
B. Decrease due to high glucose availability
C. Are not produced
D. Cause hyperglycemia

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6. Ketoacidosis is mainly caused by:

A. Excessive carbohydrate intake
B. Accumulation of ketone bodies lowering blood pH
C. Excess insulin production
D. Increased protein synthesis

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7. Which of the following conditions is characterized by ketoacidosis?

A. Type 1 diabetes mellitus
B. Hypothyroidism
C. Cushing’s syndrome
D. Hyperthyroidism

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8. Acetoacetate can spontaneously decarboxylate to form:

A. Beta-hydroxybutyrate
B. Acetone
C. Citrate
D. Pyruvate

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9. Which coenzyme is essential for ketone body utilization in peripheral tissues?

A. NADH
B. Coenzyme A
C. FAD
D. Thiamine pyrophosphate

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10. Ketone bodies cross the mitochondrial membrane:

A. By active transport
B. Freely by diffusion
C. Via specific transport proteins in plasma membrane
D. Do not cross the membrane

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✅ Answer Key: Ketone Bodies Metabolism & Ketosis

1. A – Liver mitochondria

2. B – Acetoacetate, beta-hydroxybutyrate, and acetone

3. A – HMG-CoA synthase

4. B – Brain, heart, and skeletal muscles

5. A – Increase in blood to provide alternative energy

6. B – Accumulation of ketone bodies lowering blood pH

7. A – Type 1 diabetes mellitus

8. B – Acetone

9. B – Coenzyme A

10. C – Via specific transport proteins in plasma membrane

 

Cholesterol Metabolism

1. The primary site of cholesterol synthesis in the body is:

A. Liver
B. Adipose tissue
C. Small intestine
D. Kidney

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2. The rate-limiting enzyme of cholesterol biosynthesis is:

A. HMG-CoA reductase
B. Acetyl-CoA carboxylase
C. Lipoprotein lipase
D. Cholesterol esterase

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3. Which of the following is the immediate precursor of cholesterol?

A. Mevalonate
B. Squalene
C. Acetyl-CoA
D. Farnesyl pyrophosphate

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4. Cholesterol is transported in the blood mainly as:

A. Free cholesterol
B. Triglycerides
C. Cholesteryl esters in lipoproteins
D. Phospholipids

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5. Which lipoprotein is primarily responsible for delivering cholesterol to peripheral tissues?

A. HDL
B. LDL
C. VLDL
D. Chylomicrons

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6. The process by which HDL removes cholesterol from tissues and transports it to the liver is called:

A. Cholesterol absorption
B. Reverse cholesterol transport
C. Lipolysis
D. Beta-oxidation

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7. Statins lower cholesterol levels by inhibiting:

A. LDL receptors
B. HMG-CoA reductase
C. Bile salt synthesis
D. Pancreatic lipase

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8. Excess cholesterol is excreted from the body mainly via:

A. Urine
B. Feces as bile acids
C. Sweat
D. Lungs

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9. Which of the following is a storage form of cholesterol?

A. Free cholesterol
B. Cholesteryl esters
C. Phospholipids
D. Triglycerides

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10. Familial hypercholesterolemia is caused by a defect in:

A. HMG-CoA reductase
B. LDL receptor
C. Apolipoprotein C-II
D. Lipoprotein lipase

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✅ Answer Key: Cholesterol Metabolism

1. A – Liver

2. A – HMG-CoA reductase

3. A – Mevalonate

4. C – Cholesteryl esters in lipoproteins

5. B – LDL

6. B – Reverse cholesterol transport

7. B – HMG-CoA reductase

8. B – Feces as bile acids

9. B – Cholesteryl esters

10. B – LDL receptor

 

Atherosclerosis and Prevention of Cardiovascular Diseases

1. Atherosclerosis primarily involves the accumulation of:

A. Triglycerides in the liver
B. Cholesterol and lipids in the arterial walls
C. Proteins in the kidney
D. Calcium in the bones

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2. The initial event in atherosclerosis is:

A. Platelet aggregation
B. Endothelial injury and dysfunction
C. Smooth muscle hypertrophy
D. Calcification of vessels

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3. Which lipoprotein is considered “bad cholesterol” and promotes atherosclerosis?

A. HDL
B. LDL
C. VLDL
D. Chylomicrons

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4. Foam cells in atherosclerotic plaques are derived from:

A. Smooth muscle cells
B. Macrophages that have ingested oxidized LDL
C. Platelets
D. Endothelial cells

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5. Which of the following is a major risk factor for atherosclerosis?

A. Hypotension
B. Smoking
C. Low blood glucose
D. High HDL levels

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6. Statins help prevent cardiovascular disease by:

A. Increasing triglyceride synthesis
B. Lowering LDL cholesterol levels
C. Raising blood pressure
D. Inhibiting platelet aggregation only

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7. Which lifestyle modification is NOT recommended to prevent atherosclerosis?

A. Regular exercise
B. Smoking cessation
C. High saturated fat diet
D. Maintaining healthy weight

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8. Which vitamin is known for its antioxidant properties that may help prevent atherosclerosis?

A. Vitamin C
B. Vitamin K
C. Vitamin D
D. Vitamin B12

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9. Hypertension contributes to atherosclerosis by:

A. Increasing shear stress and damaging the endothelium
B. Lowering cholesterol levels
C. Increasing insulin sensitivity
D. Reducing blood viscosity

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10. Which drug class besides statins is commonly used to reduce cardiovascular risk?

A. Beta-blockers
B. Proton pump inhibitors
C. Antihistamines
D. NSAIDs

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✅ Answer Key: Atherosclerosis and Prevention of Cardiovascular Diseases

1. B – Cholesterol and lipids in the arterial walls

2. B – Endothelial injury and dysfunction

3. B – LDL

4. B – Macrophages that have ingested oxidized LDL

5. B – Smoking

6. B – Lowering LDL cholesterol levels

7. C – High saturated fat diet

8. A – Vitamin C

9. A – Increasing shear stress and damaging the endothelium

10. A – Beta-blockers

 

Fatty Liver and Obesity

1. Fatty liver disease is characterized by:

A. Accumulation of triglycerides in hepatocytes
B. Excess protein deposition in the liver
C. Increased glycogen storage in liver
D. Inflammation of the bile ducts

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2. The most common cause of non-alcoholic fatty liver disease (NAFLD) is:

A. Viral infection
B. Obesity and insulin resistance
C. Alcohol abuse
D. Autoimmune hepatitis

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3. Which of the following is a risk factor for fatty liver disease?

A. Hypothyroidism
B. Excessive physical activity
C. Low-fat diet
D. Alcohol abuse

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4. Obesity is defined as:

A. BMI less than 18.5
B. BMI between 18.5 and 24.9
C. BMI greater than or equal to 30
D. BMI between 25 and 29.9

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5. Which hormone is primarily responsible for regulating appetite and energy balance?

A. Insulin
B. Ghrelin
C. Leptin
D. Cortisol

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6. Which type of fat distribution is associated with higher cardiovascular risk?

A. Peripheral (gynoid) obesity
B. Central (android) obesity
C. Subcutaneous fat only
D. No fat accumulation

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7. Fatty liver can progress to which serious liver condition if untreated?

A. Cirrhosis
B. Hepatitis A
C. Gallstones
D. Pancreatitis

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8. Which of the following is NOT a common complication of obesity?

A. Type 2 diabetes mellitus
B. Hypertension
C. Osteoporosis
D. Sleep apnea

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9. The main treatment for non-alcoholic fatty liver disease includes:

A. Antiviral medications
B. Weight loss and lifestyle modification
C. High-calorie diet
D. Corticosteroids

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10. Which adipose tissue secretes inflammatory cytokines contributing to metabolic complications?

A. Brown adipose tissue
B. White adipose tissue
C. Beige adipose tissue
D. Muscle tissue

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✅ Answer Key: Fatty Liver and Obesity

1. A – Accumulation of triglycerides in hepatocytes

2. B – Obesity and insulin resistance

3. D – Alcohol abuse

4. C – BMI greater than or equal to 30

5. C – Leptin

6. B – Central (android) obesity

7. A – Cirrhosis

8. C – Osteoporosis

9. B – Weight loss and lifestyle modification

10. B – White adipose tissue

Revision Questions

1. The precursor for fatty acid synthesis is:
   A. Propionyl‑CoA
   B. Malonyl‑CoA
   C. Acetyl‑CoA
   D. Methylmalonyl‑CoA

2. Which enzyme is rate‑limiting in fatty acid synthesis?
   A. Fatty acid synthase complex
   B. Acetyl‑CoA carboxylase
   C. HMG‑CoA reductase
   D. Carnitine acyltransferase I

3. All of the following are required for acetyl‑CoA carboxylase activity except:
   A. Biotin
   B. ATP
   C. Bicarbonate
   D. NADH

4. In fatty acid synthesis, the most commonly produced fatty acid by the human fatty acid synthase is:
   A. Stearic acid (18:0)
   B. Palmitic acid (16:0)
   C. Oleic acid (18:1)
   D. Linoleic acid (18:2)

5. Which of the following activates acetyl‑CoA carboxylase?
   A. High AMP
   B. Glucagon
   C. High citrate
   D. Palmitoyl‑CoA

6. Carnitine acyltransferase I is inhibited by:
   A. Malonyl‑CoA
   B. Glucagon
   C. High free CoA
   D. High ATP

7. How many cycles of β‑oxidation will palmitic acid (16:0) undergo?
   A. 6
   B. 7
   C. 8
   D. 9

8. Which of the following is produced during oxidation of odd‑chain fatty acids but not even‑chain?
   A. Acetyl‑CoA
   B. Propionyl‑CoA
   C. Acetoacetate
   D. NADH

9. Ketone bodies are synthesized primarily in which organ?
   A. Brain
   B. Liver
   C. Muscle
   D. Kidney

10. Which enzyme is the rate‑limiting enzyme of ketone body synthesis?
    A. HMG‑CoA lyase
    B. HMG‑CoA reductase
    C. Acetoacetyl‑CoA thiolase
    D. Thiophorase

11. Which lipoprotein has the highest percentage of cholesterol (relative to its other lipid components)?
    A. Chylomicron
    B. VLDL
    C. LDL
    D. HDL

12. Which apoprotein activates lipoprotein lipase?
    A. Apo B‑100
    B. Apo A‑1
    C. Apo C‑II
    D. Apo E

13. Which of the following lipids is not synthesized by human body and must come from diet?
    A. Palmitic acid
    B. Oleic acid
    C. Linoleic acid
    D. Stearic acid

14. The reducing equivalents used for fatty acid synthesis are primarily obtained from:
    A. Glycolysis (GAP dehydrogenase)
    B. TCA cycle directly
    C. Pentose‑phosphate pathway (HMP)
    D. β‑oxidation

15. Which statement is true about peroxisomal β‑oxidation?
    A. Fully oxidises fatty acids to CO₂ and H₂O
    B. Generates FADH₂ which enters electron transport chain
    C. Shortens very long chain fatty acids before mitochondria take over
    D. Occurs in the mitochondrial matrix

16. The synthesis of cholesterol is rate‑limiting at which enzyme?
    A. Squalene synthase
    B. HMG‑CoA lyase
    C. HMG‑CoA reductase
    D. Mevalonate kinase

17. Which enzyme converts HMG‑CoA to mevalonate?
    A. HMG‑CoA synthase
    B. HMG‑CoA lyase
    C. HMG‑CoA reductase
    D. Mevalonate decarboxylase

18. Cholesterol is converted into bile acids in which part of liver cell?
    A. Mitochondria
    B. Cytosol
    C. Smooth endoplasmic reticulum (SER)
    D. Golgi apparatus

19. The defect in which enzyme causes familial hypercholesterolemia (Type IIa)?
    A. Apo C‑II deficiency
    B. LDL receptor defect
    C. Lipoprotein lipase deficiency
    D. LCAT deficiency

20. Which enzyme catalyses the esterification of cholesterol to cholesteryl esters in HDL particles?
    A. Lecithin:cholesterol acyltransferase (LCAT)
    B. Cholesteryl ester transfer protein (CETP)
    C. Acyl‑CoA:cholesterol acyltransferase (ACAT)
    D. Lipoprotein lipase (LPL)

21. Which enzyme deficiency leads to accumulation of cerebrosides (glucocerebroside)?
    A. Hexosaminidase A
    B. Sphingomyelinase
    C. Glucocerebrosidase
    D. Galactocerebrosidase

22. In diabetes with high lipolysis, which enzyme is activated in adipose tissue?
    A. Lipoprotein lipase
    B. Hormone‑sensitive lipase
    C. HMG‑CoA reductase
    D. Acetyl‑CoA carboxylase

23. What is the ATP yield (net) from complete oxidation of palmitate (16C) in liver assuming standard P/O values?
    A. ~106 ATP
    B. ~129 ATP
    C. ~80 ATP
    D. ~96 ATP

24. During starvation, what happens to malonyl‑CoA levels in liver, and how does that affect fatty acid oxidation?
    A. Malonyl‑CoA increases → inhibits CPT I → reduces FA oxidation
    B. Malonyl‑CoA decreases → removes inhibition of CPT I → increases FA oxidation
    C. Malonyl‑CoA unchanged → no effect on CPT I
    D. Malonyl‑CoA decreases → inhibits CPT I → reduces FA oxidation

25. Which lipoprotein is responsible for reverse cholesterol transport (from tissues back to liver)?
    A. Chylomicrons
    B. VLDL
    C. LDL
    D. HDL

26. Which cofactor is required by acyl‑CoA dehydrogenase in the first step of β‑oxidation?
    A. NAD⁺
    B. FAD
    C. FMN
    D. Coenzyme A

27. Which of the following statements is true regarding ketone bodies?
    A. Only liver can use ketone bodies for energy.
    B. Heart can use acetoacetate and β‑hydroxybutyrate.
    C. Liver lacks enzyme for ketone body formation.
    D. Ketone bodies are synthesized by skeletal muscle.

28. In lipoprotein metabolism, the nascent chylomicron contains which apoprotein?
    A. Apo B‑100
    B. Apo B‑48
    C. Apo E
    D. Apo C‑II

29. Which of the following is not a function of cholesterol in the body?
    A. Precursor for steroid hormones
    B. Component of bile salts
    C. Needed for vitamin B12 absorption
    D. Structural component of cell membranes

30. Which enzyme hydrolyses triglycerides in adipose tissue during fasting?
    A. Lipoprotein lipase
    B. Hormone‑sensitive lipase
    C. Pancreatic lipase
    D. Intestinal lipase

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Answer Key