free bio chemistry MCQs
free bio chemistry MCQs
1. Allsoteric activator of glutamate dehydrogenase is
(A) ATP
(B) GTP
(C) ADP and GDP
(D) AMP and GMP
2. Free ammonia is
released during
(A) Oxidative deamination of glutamate
(B) Catabolism of purines
(C) Catabolism of pyrimidines
(D) All of these
3. An organ which is extremely sensitive to ammonia toxicity is
(A) Liver
(B) Brain
(C) Kidney
(D) Heart
4. Ammonia is transported from muscles to liver mainly in the form of
(A) Free ammonia
(B) Glutamine
(C) Asparagine
(C) Alanine
5. The major site of urea synthesis is
(A) Brain
(B) Kidneys
(C) Liver
(D) Muscles
6. Carbamoyl phosphate required for urea synthesis is formed in
(A) Cytosol
(B) Mitochondria
(C) Both (A) and (B)
(D) None of these
7. Cytosolic and mitochondrial carbamoyl phosphate synthetase have the following similarity:
(A) Both use ammonia as a substance
(B) Both provide carbamoyl phosphate for urea synthesis
(C) Both require N-acetylglutamate as an activator
(D) Both are allosteric enzymes
8. The following enzyme of urea cycle is present in cytosol:
(A) Argininosuccinic acid synthetase
(B) Argininosuccinase
(C) Arginase
(D) All of these
9. ATP is required in following reactions of urea cycle
: (A) Synthesis of carbamoyl phosphate and citrulline
(B) Synthesis of citrulline and argininosuccinate
(C) Synthesis of argininosuccinate and arginine
(D) Synthesis of carbamoyl phosphate and argininosuccinate
10. Daily excretion of nitrogen by an adult man is about
(A) 15–20 mg
(B) 1.5–2 gm
(C) 5–10 gm
(D) 15–20 gm
11. Maple syrup urine diseases is an inborn error of metabolism of
(A) Sulphur-containing amino acids
(B) Aromatic amino acids
(C) Branched chain amino acids
(D) Dicarboxylic amino acids
12. Cystinuria results from inability to
(A) Metabolise cysteine
(B) Convert cystine into cysteine
(C) Incorporate cysteine into proteins
(D) Reabsorb cystine in renal tubules
13. The defective enzyme in histidinemia is
(A) Histidine carboxylase
(B) Histidine decarboxylase
(C) Histidase
(D) Histidine oxidase
14. All the following statements about phenylketonuria are correct except
(A) Phenylalanine cannot be converted into tyrosine
(B) Urinary excretion of phenylpyruvate and phenyllactate is increased
(C) It can be controlled by giving a lowphenylalanine diet
(D) It leads to decreased synthesis of thyroid hormones, catecholamines and melanin
15. All the following statements about albinism are correct except
(A) Tyrosine hydroxylase (tyrosinase) is absent or deficient in melanocytes
(B) Skin is hypopigmented
(C) It results in mental retardation
(D) Eyes are hypopigmented
(A) Oxidative deamination of glutamate
(B) Catabolism of purines
(C) Catabolism of pyrimidines
(D) All of these
3. An organ which is extremely sensitive to ammonia toxicity is
(A) Liver
(B) Brain
(C) Kidney
(D) Heart
4. Ammonia is transported from muscles to liver mainly in the form of
(A) Free ammonia
(B) Glutamine
(C) Asparagine
(C) Alanine
5. The major site of urea synthesis is
(A) Brain
(B) Kidneys
(C) Liver
(D) Muscles
6. Carbamoyl phosphate required for urea synthesis is formed in
(A) Cytosol
(B) Mitochondria
(C) Both (A) and (B)
(D) None of these
7. Cytosolic and mitochondrial carbamoyl phosphate synthetase have the following similarity:
(A) Both use ammonia as a substance
(B) Both provide carbamoyl phosphate for urea synthesis
(C) Both require N-acetylglutamate as an activator
(D) Both are allosteric enzymes
8. The following enzyme of urea cycle is present in cytosol:
(A) Argininosuccinic acid synthetase
(B) Argininosuccinase
(C) Arginase
(D) All of these
9. ATP is required in following reactions of urea cycle
: (A) Synthesis of carbamoyl phosphate and citrulline
(B) Synthesis of citrulline and argininosuccinate
(C) Synthesis of argininosuccinate and arginine
(D) Synthesis of carbamoyl phosphate and argininosuccinate
10. Daily excretion of nitrogen by an adult man is about
(A) 15–20 mg
(B) 1.5–2 gm
(C) 5–10 gm
(D) 15–20 gm
11. Maple syrup urine diseases is an inborn error of metabolism of
(A) Sulphur-containing amino acids
(B) Aromatic amino acids
(C) Branched chain amino acids
(D) Dicarboxylic amino acids
12. Cystinuria results from inability to
(A) Metabolise cysteine
(B) Convert cystine into cysteine
(C) Incorporate cysteine into proteins
(D) Reabsorb cystine in renal tubules
13. The defective enzyme in histidinemia is
(A) Histidine carboxylase
(B) Histidine decarboxylase
(C) Histidase
(D) Histidine oxidase
14. All the following statements about phenylketonuria are correct except
(A) Phenylalanine cannot be converted into tyrosine
(B) Urinary excretion of phenylpyruvate and phenyllactate is increased
(C) It can be controlled by giving a lowphenylalanine diet
(D) It leads to decreased synthesis of thyroid hormones, catecholamines and melanin
15. All the following statements about albinism are correct except
(A) Tyrosine hydroxylase (tyrosinase) is absent or deficient in melanocytes
(B) Skin is hypopigmented
(C) It results in mental retardation
(D) Eyes are hypopigmented
16. Glycine is not required for the formation of
(A) Taurocholic acid
(B) Creatine
(C) Purines
(D) Pyrimidines
17. Histamine is formed from histidine by
(A) Deamination
(B) Dehydrogenation
(C) Decarboxylation
(D) Carboxylation
18. DOPA is an intermediate in the synthesis of
(A) Thyroid hormones
(B) Catecholamines
(C) Melanin
(D) Catecholamines and melanin
19. All the following statements about pepsin are correct except
(A) It is smaller than pepsinogen
(B) It is formed by the action of HCl on its precursor
(C) Its optimum pH is 1.0–2.0
(D) It hydrolyses the C-terminal and N-terminal peptide bonds of proteins
20. Pancreatic juice contains the precursors of all of the following except
(A) Trypsin
(B) Chymotrypsin
(C) Carboxypeptidase
(D) Aminopeptidase
21. The only correct statement about chymotrypsin is
(A) It is formed from trypsin
(B) Carboxypeptidase converts trypsin into chymotrypsin
(C) Its optimum pH is around 7
(D) It hydrolyses peptide bonds involving basic amino acids
22. The portion of the antigen molecule which is recognized by antibody is known as
(A) Hapten
(B) Epitope
(C) Complement
(D) Variable region
23. All the following statements about haptens are true except
(A) They have high molecular weights
(B) They cannot elicit an immune response by themselves
(C) When combined with some other large molecule, they can elicit an immune response
(D) Once an immune response develops, the free hapten can be recognized by the antibody
24. Antigens and haptens have the following similarity:
(A) They have high molecular weights
(B) They can elicit immune response by themselves
(C) They can elicit an immune response only in association with some other large molecule
(D) Once an immune response develops, free antigen and free hapten can be recognized by the antibody
25. The minimum number of polypeptide chains in an immunoglobulin is
(A) Two
(B) Four
(C) Five
(D) Six
26. Light chains of immunoglobulins are of following types:
(A) Alpha and kappa
(B) Alpha and gamma
(C) Lambda and delta
(D) Kappa and lambda
27 Immunoglobulins are classified on the basis of
(A) Type of light chains
(B) Type of heavy chains
(C) Types of light and heavy chains
(D) Molecular weight
28. The molecular weight of light chains is
(A) 10,000–15,000
(B) 20,000–25,000
(C) 25,000–50,000
(D) 50,000–75,000
29. The molecular weight of heavy chains is
(A) 20,000–25,000
(B) 25,000–50,000
(C) 50,000–70,000
(D) 70,000–1,00,000
30. Secretory component is present in
(A) IgA
(B) IgG
(C) IgM
(D) All of these
31. The variable region of light chains is the
(A) N-terminal quarter
(B) N-terminal half
(C) C-terminal quarter
(D) C-terminal half
(A) Taurocholic acid
(B) Creatine
(C) Purines
(D) Pyrimidines
17. Histamine is formed from histidine by
(A) Deamination
(B) Dehydrogenation
(C) Decarboxylation
(D) Carboxylation
18. DOPA is an intermediate in the synthesis of
(A) Thyroid hormones
(B) Catecholamines
(C) Melanin
(D) Catecholamines and melanin
19. All the following statements about pepsin are correct except
(A) It is smaller than pepsinogen
(B) It is formed by the action of HCl on its precursor
(C) Its optimum pH is 1.0–2.0
(D) It hydrolyses the C-terminal and N-terminal peptide bonds of proteins
20. Pancreatic juice contains the precursors of all of the following except
(A) Trypsin
(B) Chymotrypsin
(C) Carboxypeptidase
(D) Aminopeptidase
21. The only correct statement about chymotrypsin is
(A) It is formed from trypsin
(B) Carboxypeptidase converts trypsin into chymotrypsin
(C) Its optimum pH is around 7
(D) It hydrolyses peptide bonds involving basic amino acids
22. The portion of the antigen molecule which is recognized by antibody is known as
(A) Hapten
(B) Epitope
(C) Complement
(D) Variable region
23. All the following statements about haptens are true except
(A) They have high molecular weights
(B) They cannot elicit an immune response by themselves
(C) When combined with some other large molecule, they can elicit an immune response
(D) Once an immune response develops, the free hapten can be recognized by the antibody
24. Antigens and haptens have the following similarity:
(A) They have high molecular weights
(B) They can elicit immune response by themselves
(C) They can elicit an immune response only in association with some other large molecule
(D) Once an immune response develops, free antigen and free hapten can be recognized by the antibody
25. The minimum number of polypeptide chains in an immunoglobulin is
(A) Two
(B) Four
(C) Five
(D) Six
26. Light chains of immunoglobulins are of following types:
(A) Alpha and kappa
(B) Alpha and gamma
(C) Lambda and delta
(D) Kappa and lambda
27 Immunoglobulins are classified on the basis of
(A) Type of light chains
(B) Type of heavy chains
(C) Types of light and heavy chains
(D) Molecular weight
28. The molecular weight of light chains is
(A) 10,000–15,000
(B) 20,000–25,000
(C) 25,000–50,000
(D) 50,000–75,000
29. The molecular weight of heavy chains is
(A) 20,000–25,000
(B) 25,000–50,000
(C) 50,000–70,000
(D) 70,000–1,00,000
30. Secretory component is present in
(A) IgA
(B) IgG
(C) IgM
(D) All of these
31. The variable region of light chains is the
(A) N-terminal quarter
(B) N-terminal half
(C) C-terminal quarter
(D) C-terminal half
32. The variable region of light chain is the
(A) N-terminal quarter
(B) N-terminal half
(C) C-terminal quarter
(D) C-terminal half
33. The variable region of light chains has
(A) One hypervariable region
(B) Two hypervariable regions
(C) Three hypervariable regions
(D) Four hypervariable regions
34. The variable region of heavy chains has
(A) One hypervariable region
(B) Two hypervariable regions
(C) Three hypervariable regions
(D) Four hypervariable regions
35. The most abundant immunoglobulin in plasma is
(A) IgA
(B) IgG
(C) IgM
(D) IgD
36. The largest immunoglobulin is
(A) IgA
(B) IgG
(C) IgM
(D) IgD
37. The plasma concentration of IgA is
(A) 1–5 mg/dl
(B) 40–200 mg/dl
(C) 60–500 mg/dl
(D) 700–1,500 mg/dl
38. An immunoglobulin found in exocrine secretions is
(A) IgA
(B) IgG
(C) IgM
(D) IgE
39. Allergic reactions are mediated by
(A) IgA
(B) IgG
(C) IgD
(D) IgE
40. An immunoglobulin which can cross the placental barrier is
(A) IgA
(B) IgM
(C) IgD
(D) None of these
41. IgM possesses
(A) Two light chains and two heavy chains
(B) Four light chains and four heavy chains
(C) Six light chains and six heavy chains
(D) Ten light chains and ten heavy chains
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