MCQs on Enzymes, Vitamins, Minerals and Nutrition with Explanations. GPAT, NIPER, AIIMS Pharmacist, Railway Pharmacist, SSC, ESIC, and State Pharmacist examinations

Quick Revision Notes: Enzymes, Vitamins, Minerals, and Nutrition

1. Enzymes: Definition and Properties

• Enzymes are biological catalysts that increase the rate of biochemical reactions without being consumed.

• Most enzymes are proteins, except a few RNA molecules called ribozymes.

• Enzymes are highly specific for their substrates and reactions.

• They work under mild physiological conditions of temperature and pH.

• Enzymes lower the activation energy of a reaction.

• Most enzymes are named by adding the suffix "-ase" to the substrate or reaction type (e.g., urease, lactase, oxidase).

Remember:

Enzymes are FAST because they are:

• F – Functional catalysts

• A – Act in small amounts

• S – Specific in action

• T – Temperature and pH sensitive

2. Cofactors, Coenzymes and Prosthetic Groups

Many enzymes require non-protein components for activity.

Cofactor

A non-protein substance required for enzyme activity.

Coenzyme

Organic cofactors loosely attached to enzymes.

Examples:

• NAD⁺ → Vitamin B3 (Niacin)

• FAD → Vitamin B2 (Riboflavin)

• Coenzyme A → Vitamin B5 (Pantothenic acid)

• Pyridoxal phosphate (PLP) → Vitamin B6

Prosthetic Group

A cofactor tightly bound to an enzyme.

Important Formula

Apoenzyme + Cofactor = Holoenzyme

3. IUB Classification of Enzymes

The International Union of Biochemistry classifies enzymes into six major classes.

• Class Function Example

• Oxidoreductases Oxidation-reduction reactions Dehydrogenase

• Transferases Transfer of groups Hexokinase

• Hydrolases Hydrolysis reactions Lipase

• Lyases Addition or removal of groups without hydrolysis Decarboxylase

• Isomerases Rearrangement reactions Racemase

• Ligases Joining molecules using ATP DNA ligase

4. Enzyme Kinetics

Michaelis Constant (Km)

Km is the substrate concentration at which the reaction velocity becomes half of Vmax.

Interpretation of Km

• Low Km → High affinity

• High Km → Low affinity

Vmax

Maximum velocity is achieved when all enzyme active sites are saturated with substrate.

Important Rule:

Km and affinity are inversely related.

5. Michaelis-Menten Plot

• Graph between substrate concentration (S) and reaction velocity (V).

• Produces a hyperbolic curve.

• Shows that enzyme activity increases with substrate concentration until saturation occurs.

6. Lineweaver-Burk Plot

• Also called the double reciprocal plot.

• Graph between 1/V and 1/[S].

• Produces a straight line.

Important Points:

• X-intercept = −1/Km

• Y-intercept = 1/Vmax

Remember:

X gives Km and Y gives Vmax.

7. Enzyme Inhibitors

Competitive Inhibition

• The inhibitor competes with the substrate for the active site.

• Km increases.

• Vmax remains unchanged.

Examples:

• Malonate → Succinate dehydrogenase

• Methotrexate → Dihydrofolate reductase

• Sulfonamides → PABA pathway

Non-competitive Inhibition

• The inhibitor binds away from the active site.

• Vmax decreases.

• Km remains unchanged.

Examples:

• Cyanide

• Heavy metals

Irreversible Inhibition

The enzyme is permanently inactivated.

Examples:

• Aspirin → Cyclooxygenase

• Organophosphates → Acetylcholinesterase

Memory Trick:

Competitive changes Km; non-competitive changes Vmax.

8. Regulation of Enzymes

Enzyme Induction

Increase in enzyme synthesis due to substrate or drug exposure.

Example: Phenobarbital induces liver microsomal enzymes.

Enzyme Repression

Decrease in enzyme synthesis due to end-product accumulation.

Allosteric Regulation

Regulatory molecules bind to a site other than the active site.

Characteristics:

• Multiple subunits

• Sigmoidal kinetics

• Feedback regulation

9. Therapeutic Uses of Enzymes

• Enzyme Clinical Use

• Streptokinase Dissolves blood clots

• Urokinase Thrombolytic therapy

• Asparaginase Acute lymphoblastic leukemia

• Hyaluronidase Improves spread of injected drugs

• DNase Cystic fibrosis

Remember:

"SK saves clot, ASP treats ALL."

10. Diagnostic Uses of Enzymes and Isoenzymes

• Enzyme Clinical Importance

• Amylase Pancreatitis

• Lipase Pancreatitis

• ALT (SGPT) Liver disease

• AST (SGOT) Liver and heart disease

• ALP Bone and liver disorders

• CK-MB Myocardial infarction

Important Isoenzymes

• CK-MB → Heart

• CK-MM → Skeletal muscle

• CK-BB → Brain

• LDH1 → Heart

11. Factors Affecting Enzyme Activity

1. Temperature

2. pH

3. Substrate concentration

4. Enzyme concentration

5. Presence of inhibitors

6. Presence of activators and cofactors

Optimum Conditions

• Temperature: 37°C

• Pepsin pH: 1.5–2

• Trypsin pH: 8

Digestion and Absorption of Nutrients

12. Carbohydrate Digestion

• Site Enzyme

• Mouth Salivary amylase

• Small intestine Pancreatic amylase

• Intestinal brush border Maltase, Lactase, Sucrase

Final products absorbed:

• Glucose

• Fructose

• Galactose

Remember:

Carbohydrate digestion starts in the mouth and ends in the intestine.

13. Protein Digestion

• Site Enzyme

• Stomach Pepsin

• Pancreas Trypsin, Chymotrypsin

• Intestin Peptidases

Final products absorbed:

• Amino acids

• Small peptides

14. Fat Digestion

• Bile salts emulsify fats.

• Pancreatic lipase breaks triglycerides into fatty acids and monoglycerides.

• Absorption occurs mainly in the small intestine.

Remember:

Bile emulsifies; lipase digests.

15. Absorption of Minerals

• Mineral Site of Absorption

• Iron Duodenum

• Calcium Duodenum and jejunum

• Vitamin B12 Ileum

• Vitamin D enhances calcium absorption.

Vitamins and Deficiency Diseases

Fat-Soluble Vitamins

• Vitamin Function Deficiency

• A Vision Night blindness

• D Calcium absorption Rickets, Osteomalacia

• E Antioxidant Hemolytic anemia

• K Blood clotting Bleeding tendency

Memory Trick:

"ADEK stay with FAT."

Water-Soluble Vitamins

• Vitamin Major Function Deficiency Disease

• B1 (Thiamine) Carbohydrate metabolism Beriberi

• B2 (Riboflavin) Oxidation reactions Cheilosis

• B3 (Niacin) NAD and NADP synthesis Pellagra

• B6 (Pyridoxine) Amino acid metabolism Neuropathy

• B9 (Folic acid) DNA synthesis Megaloblastic anemia

• B12 (Cobalamin) RBC maturation Pernicious anemia

• Vitamin C Collagen synthesis Scurvy

Easy Mnemonic for Pellagra:

The 3 Ds of Pellagra

• Dermatitis

• Diarrhea

• Dementia

16. High-Yield One-Liners for Exams

• Low Km means high substrate affinity.

• Competitive inhibitors increase Km.

• Non-competitive inhibitors decrease Vmax.

• CK-MB is a marker of myocardial infarction.

• ALT is more specific for liver injury than AST.

• Vitamin D increases calcium absorption.

• Intrinsic factor is required for Vitamin B12 absorption.

• Iron absorption occurs mainly in the duodenum.

• Bile salts emulsify fats but do not digest them.

• Enzymes lower activation energy but do not alter equilibrium.

Final Memory Formula

"Low Km = Loves substrate More."

"Competitive changes Km; Non-competitive changes Vmax."

"ADEK with Fat, B and C with Water."

Enzymes and Coenzymes

1. Which of the following enzymes does not require a cofactor for activity?
A. Carbonic anhydrase
B. Catalase
C. Pepsin
D. Hexokinase

Answer: C
Explanation: Pepsin is a simple protein enzyme and does not require a cofactor.

2. The term "holoenzyme" refers to:
A. Protein portion only
B. Cofactor only
C. Active enzyme with cofactor attached
D. Inactive enzyme precursor

Answer: C
Explanation: Holoenzyme = Apoenzyme + Cofactor.

3. Which vitamin acts as a coenzyme in transamination reactions?
A. Vitamin B1
B. Vitamin B6
C. Vitamin B2
D. Vitamin B12

Answer: B
Explanation: Pyridoxal phosphate (PLP), derived from vitamin B6, is essential for transamination.

4. Biotin functions primarily in:
A. Oxidation reactions
B. Carboxylation reactions
C. Hydrolysis reactions
D. Deamination reactions

Answer: B
Explanation: Biotin serves as a coenzyme for carboxylase enzymes.

5. Which coenzyme participates in one-carbon transfer reactions?
A. Coenzyme A
B. Tetrahydrofolate
C. NADP+
D. FAD

Answer: B
Explanation: Tetrahydrofolate derived from folic acid transfers one-carbon units.

IUB Classification

6. Dehydrogenases belong to which enzyme class?
A. Hydrolases
B. Transferases
C. Oxidoreductases
D. Isomerases

Answer: C
Explanation: Dehydrogenases catalyze oxidation-reduction reactions.

7. Phosphatases belong to:
A. Hydrolases
B. Ligases
C. Lyases
D. Isomerases

Answer: A
Explanation: Phosphatases remove phosphate groups by hydrolysis.

8. Decarboxylases are classified as:
A. Transferases
B. Lyases
C. Ligases
D. Hydrolases

Answer: B
Explanation: Lyases remove groups without hydrolysis or oxidation.

9. Racemases belong to which enzyme class?
A. Isomerases
B. Hydrolases
C. Oxidoreductases
D. Ligases

Answer: A
Explanation: Racemases catalyze conversion between optical isomers.

10. DNA ligase belongs to:
A. Hydrolases
B. Ligases
C. Lyases
D. Transferases

Answer: B
Explanation: DNA ligase joins DNA strands using ATP energy.

Enzyme Kinetics

11. At substrate concentrations much higher than Km, enzyme velocity approaches:
A. Zero
B. Km
C. Vmax
D. Half Vmax

Answer: C
Explanation: At saturation, all enzyme active sites are occupied.

12. Km is an indicator of:
A. Enzyme concentration
B. Catalytic activity
C. Enzyme-substrate affinity
D. pH optimum

Answer: C
Explanation: Lower Km indicates higher substrate affinity.

13. Which plot converts a hyperbolic curve into a straight line?
A. Michaelis plot
B. Arrhenius plot
C. Lineweaver-Burk plot
D. Dixon plot

Answer: C
Explanation: The double reciprocal plot gives a straight line.

14. In competitive inhibition, Vmax is:
A. Increased
B. Decreased
C. Unchanged
D. Zero

Answer: C
Explanation: Increasing substrate concentration can overcome competitive inhibition.

15. In noncompetitive inhibition, Km remains
A. Increased
B. Decreased
C. Unchanged
D. Infinite

Answer: C
Explanation: Noncompetitive inhibitors reduce Vmax without changing substrate affinity.

Enzyme Inhibition

16. Methotrexate inhibits:
A. Dihydrofolate reductase
B. Cyclooxygenase
C. Carbonic anhydrase
D. Xanthine oxidase

Answer: A
Explanation: Methotrexate is a competitive inhibitor of dihydrofolate reductase.

17. Allopurinol inhibits:
A. Lactate dehydrogenase
B. Xanthine oxidase
C. Lipase
D. Pepsin

Answer: B
Explanation: Used in gout treatment by reducing uric acid formation.

18. Penicillin inhibits bacterial
A. DNA synthesis
B. Protein synthesis
C. Cell wall synthesis enzymes
D. RNA synthesis

Answer: C
Explanation: Penicillin inhibits the transpeptidase involved in peptidoglycan synthesis.

19. Organophosphates inhibit:
A. Acetylcholinesterase
B. Monoamine oxidase
C. Catalase
D. Carbonic anhydrase

Answer: A
Explanation: This causes accumulation of acetylcholine.

20. Cyanide inhibits:
A. Cytochrome oxidase
B. Hexokinase
C. Pepsin
D. Trypsin

Answer: A
Explanation: Cyanide blocks cellular respiration.

Regulation of Enzymes

21. Lactose induces the synthesis of β-galactosidase in bacteria. This is an example of:
A. Repression
B. Feedback inhibition
C. Enzyme induction
D. Competitive inhibition

Answer: C
Explanation: The presence of a substrate stimulates enzyme synthesis.

22. Cholesterol inhibits HMG-CoA reductase synthesis by:
A. Induction
B. Repression
C. Activation
D. Covalent modification

Answer: B
Explanation: The end product suppresses enzyme formation.

23. Allosteric enzymes possess
A. One active site only
B. Regulatory binding sites
C. No active site
D. Covalently attached cofactors only

Answer: B
Explanation: Regulatory molecules bind to allosteric sites.

24. The first committed enzyme in a metabolic pathway is usually:
A. Structural enzyme
B. Allosteric enzyme
C. Digestive enzyme
D. Lysosomal enzyme

Answer: B
Explanation: It commonly regulates pathway activity.

25. Feedback inhibition is generally a form of:
A. Positive regulation
B. Negative regulation
C. Enzyme induction
D. Covalent activation

Answer: B
Explanation: End products reduce pathway activity.

Therapeutic and Diagnostic Enzymes

26. Urokinase is used clinically as:
A. Antibiotic
B. Antihypertensive
C. Thrombolytic agent
D. Antacid

Answer: C
Explanation: It dissolves blood clots.

27. Hyaluronidase is used to:
A. Dissolve kidney stones
B. Increase tissue permeability
C. Reduce blood glucose
D. Treat anemia

Answer: B
Explanation: It promotes spread of injected drugs.

28. DNase is therapeutically useful in:
A. Asthma
B. Cystic fibrosis
C. Hypertension
D. Diabetes

Answer: B
Explanation: It reduces sputum viscosity.

29. Elevated alkaline phosphatase suggests disease of:
A. Bone or liver
B. Kidney only
C. Lung only
D. Thyroid only

Answer: A
Explanation: ALP rises in bone disorders and cholestasis.

30. Increased serum ALT mainly indicates damage to:
A. Heart
B. Brain
C. Liver
D. Bone

Answer: C
Explanation: ALT is a sensitive marker of liver injury.

Isoenzymes

31. LDH1 is abundant in:
A. Liver
B. Skeletal muscle
C. Heart muscle
D. Bone

Answer: C
Explanation: LDH1 rises in myocardial infarction.

32. CK-MM is predominantly found in:
A. Brain
B. Skeletal muscle
C. Liver
D. Pancreas

Answer: B
Explanation: CK-MM is the major skeletal muscle isoenzyme.

33. CK-BB is primarily present in:
A. Brain
B. Liver
C. Kidney
D. Bone

Answer: A
Explanation: CK-BB predominates in nervous tissue.

34. Which enzyme was historically used for diagnosis of myocardial infarction?
A. ALP
B. CK-MB
C. Lipase
D. Acid phosphatase

Answer: B
Explanation: CK-MB rises within hours after cardiac injury.

Factors Affecting Enzyme Activity

35. Increasing enzyme concentration generally causes
A. Decrease in reaction velocity
B. Increase in reaction velocity
C. No effect
D. Enzyme denaturation

Answer: B
Explanation: More active sites are available.

36. Heavy metals inhibit enzymes by interacting with:
A. Amino groups
B. Sulfhydryl groups
C. Carboxyl groups
D. Phosphate groups

Answer: B
Explanation: Mercury and lead commonly bind sulfhydryl groups.

37. Extreme pH affects enzymes mainly by causing
A. Polymerization
B. Denaturation
C. Phosphorylation
D. Reduction

Answer: B
Explanation: Changes in ionization alter enzyme structure.

Digestion and Absorption

38. Salivary amylase digests:
A. Protein
B. Fat
C. Starch
D. Cellulose

Answer: C
Explanation: It converts starch into maltose and dextrins.

39. Trypsin is secreted by the pancreas as
A. Active trypsin
B. Pepsinogen
C. Trypsinogen
D. Chymotrypsin

Answer: C
Explanation: It is activated in the intestine by enterokinase.

40. Bile salts aid digestion by:
A. Hydrolyzing proteins
B. Emulsifying fats
C. Activating pepsin
D. Absorbing glucose

Answer: B
Explanation: Emulsification increases surface area for lipase action.

41. Most nutrient absorption occurs in the:
A. Stomach
B. Jejunum
C. Colon
D. Rectum

Answer: B
Explanation: The jejunum is the major absorptive site.

Vitamins and Minerals

42. Vitamin K is required for synthesis of
A. Hemoglobin
B. Clotting factors
C. Insulin
D. Thyroxine

Answer: B
Explanation: Vitamin K is essential for prothrombin synthesis.

43. Riboflavin deficiency causes:
A. Pellagra
B. Cheilosis
C. Scurvy
D. Beriberi

Answer: B
Explanation: Angular stomatitis and cheilosis are typical findings.

44. Vitamin E deficiency primarily causes:
A. Bleeding tendency
B. Hemolytic anemia
C. Night blindness
D. Rickets

Answer: B
Explanation: Vitamin E protects cell membranes from oxidation.

45. Deficiency of iodine results in:
A. Scurvy
B. Goiter
C. Beriberi
D. Pellagra

Answer: B
Explanation: Iodine is required for thyroid hormone synthesis.

46. Zinc deficiency commonly causes:
A. Delayed wound healing
B. Polycythemia
C. Hyperthyroidism
D. Hypercalcemia

Answer: A
Explanation: Zinc is important for tissue repair and immunity.

47. Copper deficiency may lead to:
A. Anemia
B. Hyperglycemia
C. Hyperlipidemia
D. Hypertension

Answer: A
Explanation: Copper is involved in iron metabolism.

48. Selenium acts mainly as a component of:
A. DNA polymerase
B. Glutathione peroxidase
C. Hexokinase
D. Pepsin

Answer: B
Explanation: Selenium contributes to antioxidant defense.

49. Magnesium acts as a cofactor for:
A. Very few enzymes
B. Hundreds of enzymes
C. Only digestive enzymes
D. Only liver enzymes

Answer: B
Explanation: Magnesium participates in numerous ATP-dependent reactions.

50. Intrinsic factor is essential for the absorption of:
A. Vitamin A
B. Vitamin D
C. Vitamin B12
D. Vitamin C

Answer: C
Explanation: Lack of intrinsic factor causes pernicious anemia.

Dr. Alok Singh

Basic Qustions (MCQs)

Enzymes: Properties, Nomenclature, and IUB Classification. .

1. Enzymes are chemically classified as:
A. Lipids
B. Carbohydrates
C. Proteins
D. Nucleic acids

Answer: C

2. The International Union of Biochemistry (IUB) classifies enzymes into how many major classes?
A. 4
B. 5
C. 6
D. 8

Answer: C

3. Oxidoreductases catalyze:
A. Hydrolysis reactions
B. Oxidation-reduction reactions
C. Transfer of functional groups
D. Isomerization reactions

Answer: B

4. Which enzyme class transfers functional groups from one molecule to another?
A. Ligases
B. Transferases
C. Lyases
D. Hydrolases

Answer: B

5. Hexokinase belongs to which IUB class?
A. Oxidoreductase
B. Transferase
C. Hydrolase
D. Lyase

Answer: B

6. Which enzyme class catalyzes bond formation coupled with ATP hydrolysis?
A. Isomerases
B. Hydrolases
C. Ligases
D. Lyases

Answer: C

7. The non-protein component tightly bound to an enzyme is called:
A. Apoenzyme
B. Prosthetic group
C. Substrate
D. Zymogen

Answer: B

8. The protein portion of a conjugated enzyme is called:
A. Coenzyme
B. Holoenzyme
C. Apoenzyme
D. Prosthetic group

Answer: C

9. Apoenzyme plus cofactor together constitute:
A. Zymogen
B. Holoenzyme
C. Isoenzyme
D. Metalloenzyme

Answer: B

10. NAD⁺ functions as a:
A. Substrate
B. Coenzyme
C. Inhibitor
D. Isoenzyme

Answer: B

Coenzymes

11. NAD⁺ is derived from which vitamin?
A. Vitamin B1
B. Vitamin B2
C. Vitamin B3
D. Vitamin B6

Answer: C

12. FAD is derived from:
A. Riboflavin
B. Pyridoxine
C. Biotin
D. Folic acid

Answer: A

13. Coenzyme A contains which vitamin?
A. Pantothenic acid
B. Riboflavin
C. Thiamine
D. Biotin

Answer: A

14. Pyridoxal phosphate is the active coenzyme form of:
A. Vitamin B1
B. Vitamin B2
C. Vitamin B6
D. Vitamin B12

Answer: C

Enzyme Kinetics

15. The Michaelis constant (Km) is defined as substrate concentration at which:
A. Enzyme activity stops
B. Velocity is maximum
C. Velocity is half of Vmax
D. Substrate is completely utilized

Answer: C

16. A low Km value indicates:
A. Low enzyme affinity for substrate
B. High enzyme affinity for substrate
C. Competitive inhibition
D. Enzyme denaturation

Answer: B

17. The Michaelis-Menten plot is a graph between:
A. 1/V and 1/[S]
B. Velocity and substrate concentration
C. Velocity and enzyme concentration
D. pH and velocity

Answer: B

18. The Lineweaver-Burk plot is also known as:
A. Double reciprocal plot
B. Saturation plot
C. Sigmoid plot
D. Arrhenius plot

Answer: A

19. In the Lineweaver-Burk plot, the X-intercept represents:
A. Vmax
B. 1/Vmax
C. -1/Km
D. Km

Answer: C

20. In the Lineweaver-Burk plot, the Y-intercept is equal to:
A. Km
B. Vmax
C. 1/Vmax
D. -1/Km

Answer: C

Enzyme Inhibition

21. Competitive inhibitors increase:
A. Vmax
B. Km
C. Both Km and Vmax
D. Neither Km nor Vmax

Answer: B

22. Which of the following is a competitive inhibitor of succinate dehydrogenase?
A. Malonate
B. Cyanide
C. Fluoride
D. Penicillin

Answer: A

23. Noncompetitive inhibitors generally:
A. Increase Vmax
B. Decrease Vmax
C. Increase Km only
D. Increase both Km and Vmax

Answer: B

24. Sulfonamides act as competitive inhibitors of:
A. PABA metabolism
B. DNA synthesis
C. Protein synthesis
D. Glycolysis

Answer: A

25. Aspirin irreversibly inhibits:
A. Cyclooxygenase
B. Hexokinase
C. Lactate dehydrogenase
D. Catalase

Answer: A

Regulation of Enzymes

26. Increased synthesis of enzyme molecules in response to substrate availability is called:
A. Repression
B. Induction
C. Inhibition
D. Activation

Answer: B

27. Reduction in enzyme synthesis due to end-product accumulation is called:
A. Enzyme induction
B. Enzyme activation
C. Enzyme repression
D. Feedback stimulation

Answer: C

28. Allosteric enzymes typically show which type of kinetic curve?
A. Linear
B. Hyperbolic
C. Sigmoidal
D. Exponential

Answer: C

29. The end product of a metabolic pathway inhibiting an early enzyme in the pathway is called:
A. Feed-forward activation
B. Feedback inhibition
C. Competitive activation
D. Enzyme induction

Answer: B

Therapeutic and Diagnostic Applications

30. Streptokinase is therapeutically used for:
A. Hypertension
B. Thrombolysis
C. Diabetes mellitus
D. Hyperlipidemia

Answer: B

31. Asparaginase is used in the treatment of:
A. Leukemia
B. Tuberculosis
C. Malaria
D. Asthma

Answer: A

32. Elevated serum amylase is commonly associated with:
A. Hepatitis
B. Pancreatitis
C. Myocardial infarction
D. Anemia

Answer: B

33. Which isoenzyme is most specific for myocardial infarction?
A. LDH1
B. LDH5
C. CK-MM
D. ALP

Answer: A

34. Creatine kinase-MB (CK-MB) is mainly associated with:
A. Liver disease
B. Skeletal muscle disease
C. Cardiac muscle injury
D. Kidney disease

Answer: C

Factors Affecting Enzyme Activity

35. The optimum temperature for most human enzymes is:
A. 25°C
B. 30°C
C. 37°C
D. 45°C

Answer: C

36. Enzyme denaturation commonly occurs at:
A. Very low temperatures
B. High temperatures
C. Neutral pH only
D. Low substrate concentration

Answer: B

37. Pepsin exhibits maximum activity at pH:
A. 1.5–2.0
B. 4–5
C. 7
D. 8–9

Answer: A

38. Trypsin functions optimally at pH:
A. 2
B. 4
C. 7.8–8.5
D. 11

Answer: C

Digestion and Absorption

39. Carbohydrate digestion begins in the:
A. Stomach
B. Mouth
C. Duodenum
D. Ileum

Answer: B

40. The principal enzyme responsible for protein digestion in the stomach is:
A. Trypsin
B. Pepsin
C. Lipase
D. Maltase

Answer: B

41. Fat digestion mainly occurs in the:
A. Stomach
B. Colon
C. Small intestine
D. Mouth

Answer: C

42. Vitamin B12 is absorbed in the:
A. Duodenum
B. Jejunum
C. Ileum
D. Colon

Answer: C

43. Iron is primarily absorbed from the:
A. Stomach
B. Duodenum
C. Ileum
D. Colon

Answer: B

44. Calcium absorption is enhanced by:
A. Vitamin A
B. Vitamin D
C. Vitamin K
D. Vitamin E

Answer: B

Vitamins and Associated Diseases

45. Deficiency of vitamin C causes:
A. Rickets
B. Pellagra
C. Scurvy
D. Beriberi

Answer: C

46. Deficiency of thiamine causes:
A. Beriberi
B. Rickets
C. Scurvy
D. Osteomalacia

Answer: A

47. Pellagra is caused by deficiency of:
A. Niacin
B. Riboflavin
C. Pyridoxine
D. Biotin

Answer: A

48. Night blindness results from deficiency of:
A. Vitamin D
B. Vitamin A
C. Vitamin E
D. Vitamin K

Answer: B

49. Deficiency of vitamin D in children causes:
A. Scurvy
B. Osteoporosis
C. Rickets
D. Beriberi

Answer: C

50. Megaloblastic anemia is commonly associated with a deficiency of:
A. Vitamin A
B. Vitamin C
C. Folic acid and Vitamin B12
D. Vitamin K

Answer: C