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3.1 Amino Acids β Test 1
Q1. Which one of the following is an acidic amino acid?β Aspartic acid
Q2. Generally, at a low pH amino acids have a net:β Positive charge
Q3. Match the amino acid with its side-chain property:β I-3, II-4, III-1, IV-2
Q4. The increasing order of side-chain-relevant pKa for Gly, Asp, Lys, Arg is:β Asp < Gly < Lys < Arg
Q5. The amino acid that lacks a pKR (side-chain pKa) value is:β Glycine
Q6. The average molecular weight of an amino acid residue in a protein is about:β 110
Q7. The average molecular weight of an amino acid residue in a protein is approximately:β 110
Q8. In the single-letter amino acid code, the letter B represents:β Either aspartate or asparagine
Q9. An amino acid has no ionizable side chain (R). Titrated from pH 0 to 14, which ionic state is NOT observed?β NHβ-CH(R)-COOH
Q10. At physiological pH, the carboxyl and amino groups of an amino acid are in the form:β βCOOβ»; βNHββΊ
Q11. All amino acids found in proteins, except proline, contain a free:β Amino group
Q12. What is the net charge of arginine at pH = 1?β +2
Q13. Positively charged (basic) amino acids are:β Lysine and arginine
Q14. Which amino acid acts as the blood buffer in haemoglobin?β Histidine
Q15. Which compound is a much stronger chelator of CaΒ²βΊ?β Ξ³-Carboxyglutamate
Q16. The amino acid pair that is most and least conformationally restricted in a polypeptide chain is:β Proline and Glycine
Q17. Which one of the following is an essential amino acid?β Threonine
Q18. Which of the following are essential amino acids?β Methionine and Tryptophan
Q19. Which amino acid is most soluble in water at pH 7.0?β Glutamate
Q20. Which amino acid is NOT optically active?β Glycine
Q21. In a highly acidic solution (pH β 1.3), glycine exists as:β βΊNHββCHββCOOH
Q22. Which amino acid has a pI greater than 10?β Arginine
Q23. Which amino acid has a pKa value near physiological pH?β Histidine
Q24. Which amino acid has a pKa near neutrality?β Histidine
Q25. Which one of the following amino acids has a pKa near neutrality?β Histidine
Q26. The hydropathy index of an amino acid represents its:β Hydrophobic and hydrophilic properties
3.1 Amino Acids β Test 2
Q27. If hydropathy index values of X and Y (on transfer from hydrophobic solvent to water) are +4.5 and β4.5, then:β X is more hydrophobic than Y
Q28. Which list contains only hydrophobic amino acids?β I,P,L,W,A
Q29. Which set consists of only apolar/hydrophobic side chains?β Ala, Leu, Ile, Phe
Q30. Which is the correct order of hydrophobicity?β Val > Ala > Tyr > Asp
Q31. Amino acids that contain a hydroxyl group in their side chains include:β Serine
Q32. Which of the following is an imino acid?β Proline
Q33. For aspartate, pK1(COOH)=1.88, pK2(NHββΊ)=9.6, pKR=3.65. At which pH will Asp not move in an electric field (its pI)?β 2.77
Q34. For aspartate (pK1=1.88, pK2=9.6, pK3=3.65), at which pH will Asp not move in an electric field?β 2.77
Q35. Calculate the pI of aspartic acid given pK1=1.99, pK2=9.90, pKR=3.90:β 2.945
Q36. For aspartate (pK1=1.88, pK2=9.6, pK3=3.65), the pH at which Asp will not move is:β 2.77
Q37. In lysine (side-chain pKa ~10.5, Ξ±-COOH ~2, Ξ±-NHββΊ ~9), the pI is closest to:β 9.8
Q38. In lysine (side-chain pKa ~10.5, carboxyl 2, amino 9), the pI is closest to:β 9.8
Q39. In lysine (side-chain pKa ~10.5, carboxyl 2.0, amino 9.0), the pI is closest to:β 9.8
Q40. What is the pI of a non-standard amino acid X with pK1=2.5, pK2=7.5, pK3=9.0?β 8.25
Q41. Which amino acid has two asymmetric (chiral) carbons?β Isoleucine
Q42. The side chain of leucine is:β (CHβ)β-CH-CHβ-
Q43. Pepsin (pI ~1) is acidic. Which amino acids must be abundant to give such a low pI?β Asp and Glu
Q44. Which amino acid is a diamino monocarboxylic acid?β Lysine
Q45. Which amino acid is a diamino monocarboxylic acid (repeat)?β Lysine
Q46. An element found in all amino acids but not in carbohydrates is:β Nitrogen
Q47. Which non-essential amino acid(s) can be synthesised in the body? 1.Threonine 2.Tryptophan 3.Tyrosine 4.Glutamineβ 3 & 4 only
Q48. Which of the following are non-essential amino acids? I.Alanine II.Histidine III.Aspartate IV.Glutamate V.Lysine VI.Tryptophanβ I, III, IV
Q49. Which set contains nonpolar, aliphatic R groups?β Gly, Ala, Leu
Q50. Which one of the following amino acids is NOT found in proteins?β Ornithine
Q51. The non-protein amino acid canavanine can be mistakenly incorporated in place of which residue?β Arginine
3.1 Amino Acids β Test 3
Q52. The peptide linkage is:β βCOβNHβ
Q53. For the peptide Lys-Arg-Gln-Asp-Cys, which statement describes its peptide bonds?β All are covalent amide bonds with partial double-bond character and trans configuration
Q54. Formation of a peptide bond between two amino acids is an example of a:β Condensation reaction
Q55. The formation of a peptide bond between two amino acids is an example of a:β Condensation reaction
Q56. A peptide associates with an amphiphile at acidic pH and dissociates at alkaline pH. This indicates the peptide is:β Anionic at alkaline pH
Q57. A tetrapeptide has four pKa values and a pI of 3.5. How many of its amino acids have an ionizable R-group?β Two
Q58. The amino acid that shows buffering capacity near the physiological pH range is:β Histidine
Q59. Which factor does NOT affect the pKa value of an amino acid?β Molecular weight
Q60. Which pair belongs to the class of polar amino acids?β Serine and asparagine
Q61. Which set consists of only polar side chains?β Ser, Asn, Gln, Thr
Q62. Using 1000 amino acids to build a polypeptide, the approximate molecular weight is:β 92018
Q63. You join 1000 amino acids into a polypeptide. The molecular weight is approximately:β 92018
Q64. The amino acids that carry a positive charge upon ionization are:β Lysine and Arginine
Q65. An amino acid that has a secondary amine and disrupts Ξ±-helix formation is:β Proline
Q66. Which residue has very restricted conformational freedom?β Proline
Q67. Which of the following does NOT form a zwitterion?β Pyruvic acid
Q68. Which pair of amino acids could form a salt bridge at pH 7.4?β Glutamate and Arginine
Q69. The amino acid sequence of the peptide 'Q-W-E-D' is:β Gln-Trp-Glu-Asp
Q70. Which are sulphur-containing amino acids?β Cysteine & Methionine
Q71. Sulphur-containing amino acids are:β Cysteine & Methionine
Q72. All of the following are sulphur-containing amino acids EXCEPT:β Threonine
Q73. All the following are sulphur-containing amino acids found in proteins EXCEPT:β Threonine
Q74. Which statement about threonine's chirality is true?β Two chiral carbons; four stereoisomers possible
Q75. Which amino acid can be estimated by the Xanthoproteic test?β Tyrosine
Q76. Which amino acid contains hydroxyl groups and can be phosphorylated?β Serine
Q77. Poly-hydroxyproline behaviour highlights that Ξ±-helix stability depends on:β Both H-bonds and side-chain nature