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FREE BIO CHEMISTRY MCQs

FREE BIO CHEMISTRY MCQs







    1.  All proteins contain the
        (A) Same 20 amino acids
        (B) Different amino acids
        (C) 300 Amino acids occurring in nature
        (D) Only a few amino acids
 
    2. Proteins contain
       (A) Only L- α - amino acids
       (B) Only D-amino acids
       (C) DL-Amino acids
       (D) Both (A) and (B)
 
   
       3. The optically inactive amino acid is
          (A) Glycine
          (B) Serine
          (C) Threonine
          (D) Valine
 
     4. At neutral pH, a mixture of amino acids in solution would be predominantly:
        (A) Dipolar ions
        (B) Nonpolar molecules
        (C) Positive and monovalent
        (D) Hydrophobic
 

     5. The true statement about solutions of amino acids at physiological pH is
         (A) All amino acids contain both positive and negative charges
         (B) All amino acids contain positively charged side chains
         (C) Some amino acids contain only positive charge
         (D) All amino acids contain negatively charged side chains

   

     6. pH (isoelectric pH) of alanine is 
         (A) 6.02 
(        (B) 6.6 
         (C) 6.8 
         (D) 7.2
      
      7. Since the pK values for aspartic acid are 2.0, 3.9 and 10.0, it follows that the isoelectric (pH) is 
          (A) 3.0
          (B) 3.9 
          (C) 5.9 
          (D) 6.0 


         8. Sulphur containing amino acid is 
           (A) Methionine 
           (B) Leucine 
           (C) Valine
           (D) Asparagine

        9. An example of sulphur containing amino acid is 
           (A) 2-Amino-3-mercaptopropanoic acid 
           (B) 2-Amino-3-methylbutanoic acid 
           (C) 2-Amino-3-hydroxypropanoic acid 
           (D) Amino acetic acid

        10. All the following are sulphur containing amino acids found in proteins except 
            (A) Cysteine 
            (B) Cystine 
            (C) Methionine 
            (D) Threonine 
     
     11. An aromatic amino acid is 
         (A) Lysine 
         (B) Tyrosine 
         (C) Taurine
         (D) Arginine

12. The functions of plasma albumin are
   (A) Osmosis
   (B) Transport
   (C) Immunity
   (D) both (A )and (B)


 13. Amino acid with side chain containing basic groups is
 (A) 2-Amino 5-guanidovaleric acid
 (B) 2-Pyrrolidine carboxylic acid
 (C) 2-Amino 3-mercaptopropanoic acid
 (D) 2-Amino propanoic acid

14. An example of α-amino acid not present in proteins but essential in mammalian metabolism is        (A) 3-Amino 3-hydroxypropanoic acid
  (B) 2-Amino 3-hydroxybutanoic acid
  (C) 2-Amino 4-mercaptobutanoic acid
  (D) 2-Amino 3-mercaptopropanoic acid

 15. An essential amino acid in man is
 (A) Aspartate
 (B) Tyrosine
 (C) Methionine
 (D) Serine

 16. Non essential amino acids
 (A) Are not components of tissue proteins
 (B) May be synthesized in the body from essential amino acids
 (C) Have no role in the metabolism
 (D) May be synthesized in the body in diseased states

 17. Which one of the following is semiessential amino acid for humans?
(A) Valine
(B) Arginine
(C) Lysine
(D) Tyrosine

18. An example of polar amino acid is
(A) Alanine
(B) Leucine
(C) Arginine
(D) Valine

 19. The amino acid with a nonpolar side chain is
(A) Serine
(B) Valine
(C) Asparagine
(D) Threonine

 20. A ketogenic amino acid is
(A) Valine
(B) Cysteine
(C) Leucine
(D) Threonine

 21. An amino acid that does not form an α- helix is
(A) Valine
(B) Proline
(C) Tyrosine
(D) Tryptophan

 22. An amino acid not found in proteins is
(A) β-Alanine
(B) Proline
(C) Lysine
(D) Histidine

23. In mammalian tissues serine can be a biosynthetic precursor of
(A) Methionine
(B) Glycine
(C) Tryptophan
(D) Phenylalanine

 24. A vasodilating compound is produced by the decarboxylation of the amino acid:
 (A) Arginine
 (B) Aspartic acid
 (C) Glutamine
 (D) Histidine

 25. Biuret reaction is specific for
(A) –CONH-linkages
(B) –CSNH2 group
(C) –(NH)NH2 group
(D) All of these

 26. Sakaguchi’s reaction is specific for
(A) Tyrosine
(B) Proline
(C) Arginine
(D) Cysteine

 27. Million-Nasse’s reaction is specific for the amino acid:
(A) Tryptophan
(B) Tyrosine
(C) Phenylalanine
(D) Arginine

28. Ninhydrin with evolution of CO2 forms a blue complex with
(A) Peptide bond
(B) α-Amino acids
(C) Serotonin
(D) Histamine

 29. The most of the ultraviolet absorption of proteins above 240 nm is due to their content of
(A) Tryptophan
(B) Aspartate
(C) Glutamate
(D) Alanine

 30. Which of the following is a dipeptide?
(A) Anserine
(B) Glutathione
(C) Glucagon
(D) β -Lipoprotein

 31. Which of the following is a tripeptide?
(A) Anserine
(B) Oxytocin
(C) Glutathione
(D) Kallidin

32. A peptide which acts as potent smooth muscle hypotensive agent is
(A) Glutathione
(B) Bradykinin
(C) Tryocidine
(D) Gramicidin-s

33. A tripeptide functioning as an important reducing agent in the tissues is
(A) Bradykinin
(B) Kallidin
(C) Tyrocidin
(D) Glutathione

 34. An example of metalloprotein is
(A) Casein
(B) Ceruloplasmin
(C) Gelatin
(D) Salmine

 35. Carbonic anhydrase is an example of
(A) Lipoprotein
(B) Phosphoprotein
(C) Metalloprotein
(D) Chromoprotein

 36. An example of chromoprotein is
(A) Hemoglobin
(B) Sturine
(C) Nuclein
(D) Gliadin

 37. An example of scleroprotein is
(A) Zein
(B) Keratin
(C) Glutenin
(D) Ovoglobulin

 38. Casein, the milk protein is
(A) Nucleoprotein
(B) Chromoprotein
(C) Phosphoprotein
(D) Glycoprotein 3

9. An example of phosphoprotein present in egg yolk is
(A) Ovoalbumin
(B) Ovoglobulin
(C) Ovovitellin
(D) Avidin

40. A simple protein found in the nucleoproteins of the sperm is
(A) Prolamine
(B) Protamine
(C) Glutelin
(D) Globulin

 41. Histones are
(A) Identical to protamine
(B) Proteins rich in lysine and arginine
(C) Proteins with high molecular weight
(D) Insoluble in water and very dilute acids

42. The protein present in hair is
(A) Keratin
(B) Elastin
(C) Myosin
(D) Tropocollagen

43. The amino acid from which synthesis of the protein of hair keratin takes place is
(A) Alanine
(B) Methionine
(C) Proline
(D) Hydroxyproline

44. In one molecule of albumin the number of amino acids is
(A) 510
(B) 590
(C) 610
(D) 650

 45. Plasma proteins which contain more than 4% hexosamine are
(A) Microglobulins
(B) Glycoproteins
(C) Mucoproteins
(D) Orosomucoids

 46. After re leas ing O2 at the tissues, hemoglobin transports
(A) CO2 and protons to the lungs
(B) O2 to the lungs
(C) CO2 and protons to the tissue
(D) Nutrients

 47. Ehlers-Danlos syndrome characterized by hypermobile joints and skin abnormalities is due to (A) Abnormality in gene for procollagen
(B) Deficiency of lysyl oxidase
(C) Deficiency of prolyl hydroxylase
(D) Deficiency of lysyl hydroxylase

48. Proteins are soluble in
(A) Anhydrous acetone
(B) Aqueous alcohol
(C) Anhydrous alcohol
(D) Benzene

49. A cereal protein soluble in 70% alcohol but insoluble in water or salt solution is
(A) Glutelin
(B) Protamine
(C) Albumin
(D) Gliadin

50. Many globular proteins are stable in solution inspite they lack in
(A) Disulphide bonds
(B) Hydrogen bonds
(C) Salt bonds
(D) Non polar bonds

51. The hydrogen bonds between peptide linkages of a protein molecules are interfered by
(A) Guanidine
(B) Uric acid
(C) Oxalic acid
(D) Salicylic acid

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