Chapter 3 review

42. The net charge on the amino acid cys in a solution at pH 7 is closest to A. -2 B. -1. C. 0. D. +1.

0

56. The net charge on the peptide abbreviated CAKE in a solution at pH 7 is closest to A. -2 B. -1. C. 0. D. +1.

0

16. Asp and Glu both have amides as side chains. A. True B. False

False

75. Which amino acid occurs only in the protein thyroglobulin? A. tryptophan B. methionine C. arginine D. thyroxine

thyroxine

17. Thr and Ser both have hydroxyls as side chains. A. True B. False

true

18. The side chain of Met is a poor hydrogen bond donor. A. True B. False

true

22. Which amino acid takes on a negative charge when the R-group loses a proton? A. Glutamic Acid B. Histidine C. Glutamine D. Tyrosine E. Glutamic Acid and Tyrosine

glutamic acid and tyrosine

35. What is the charge on the tetrapeptide lys-lys-his-glu at pH 7? A. 0 B. +1 C. +2 D. -1

+1

63. How many possible tetrapeptides can be made using all four of the amino acids D, W, F, and R? A. 4 B. 6 C. 12 D. 24

24

65. How many different tripeptides can be assembled using one molecule each of the amino acids glycine, glutamic acid, and lysine? A. 3 B. 6 C. 9 D. 27

6

64. This amino acid displays a free amino group in the peptide ALA-GLN-ARG-SER-HIS: A. ALA B. GLN C. SER D. HIS

ALA

14. Which of the following has a hydrophilic side chain? A. Asn B. Leu C. Ile D. Gly

Asn

10. Which is a correct pair of abbreviations for an amino acid? A. Gln / N B. Tyr / T C. Asn / N D. Phe / P E. Pro / Q

Asn/N

40. Which of the following correctly lists the isoelectric pH's of asp, asn, and arg from lowest to highest? A. D N R B. D R N C. R N D D. R D N E. N R D F. N D R

D N R

25. Which amino acid is often added to other molecules to increase their water solubility? A. Ala B. Asp C. Gly D. Pro E. Trp

Gly

12. Which amino acid is classified as polar? A. L B. H C. P D. I

H

67. Which is the C-terminal amino acid in the peptide ALA-GLN-ARG-SER-HIS? A. ALA B. GLN C. ARG D. SER E. HIS

HIS

15. Which of the following amino acids has a side chain that can make hydrogen bonds to other molecules? A. Leu B. Ser C. Ala D. Gly

Ser

70. The peptide bond A. is planar B. can be written as a resonance hybrid C. is the basis of protein structure. D. all of the above

all of the above

62. Which of the following correctly describes peptide bonds? A. They are special type of amide bond. B. They are a very stable bonds. C. They are formed when water is split out from an amino group and a carboxylic acid. D. They are a bond which displays resonance. E. All of these

all of these

6. The amino acids which occur in proteins A. are all of the L- form. B. are all of the D- form. C. can be either the L- or D- form. D. do not have L- and D- forms.

are all of the L- form

3. Chiral objects A. are cyclic compounds in the chair form. B. are not superimposable on their mirror images. C. never occur in nature. D. do not form crystals.

are not superimposable on their mirror images

77. Oxytocin and vasopressin A. differ from each other by a single amino acid B. do not contain sulfur C. are peptide hormones D. are tripeptides

are peptide hormones

9. Which amino acid has the three-letter symbol asn? A. aspartic acid B. asparagine C. alanine D. arginine

asparagine

19. Which group consists only of amino acids with carboxylate side chains? A. glutamate and cysteine B. aspartate and glycine C. glutamate and lysine D. aspartate and glutamate

aspartate and glutamate

34. Which amino acids would migrate furthest toward the anode (positive electrode) during electrophoresis? A. Aspartic acid. B. Arginine. C. Tyrosine. D. Histidine. E. Glutamine.

aspartic acid

74. The following molecules are all short peptides except: A. b-alanine B. Aspartame C. Met-Enkephalin D. Glutathione E. Oxytocin

b-alanine

1. The amino and carboxyl groups of amino acids are bonded to which carbon? A. Both are bonded to the a-carbon. B. Both are bonded to the b-carbon. C. The amino is bonded to the a-carbon, and the carboxyl is bonded to the b-carbon. D. The amino is bonded to the b-carbon, and the carboxyl is bonded to the a-carbon.

both are bonded to the a-carbon

55. At its isolectric pH, glycine will have A. both of its ionizable functional groups dissociated. B. neither of its ionizable functional groups dissociated. C. only its carboxyl group dissociated. D. only its amino group dissociated.

both of its ionizable functional groups dissociated

21. Which amino acids contain sulfur? A. cysteine and lysine B. cysteine and methionine C. arginine and methionine D. cysteine and isoleucine

cysteine and methionine

37. The pKa values of the side chains of the common amino acids A. are always at low pH B. are always at high pH C. depend on the chemical nature of the side chain D. are not known

depend on the chemical nature of the side chain

69. The order in which amino acids are linked in peptides is given A. from the C-terminal to the N-terminal end B. from the N-terminal to the C-terminal end C. in alphabetical order D. in order of increasing molecular weights of the amino acid residues

from the N terminal to the C terminal end

28. Which amino acid would have the greatest negative charge at pH = 7.0? A. Glutamic Acid B. Histidine C. Isoleucine D. Serine E. Tyrosine

glutamic acid

8. Which amino acid has the one-letter symbol E? A. lysine B. phenylalanine C. histidine D. glutamic acid

glutamic acid

5. The absolute configuration of amino acids are denoted by their relationship to the L- or D- forms of A. glyceraldehyde B. glucose C. tartaric acid D. alanine

glyceraldehyde

4. Which of the following has no L or D configuration? A. Glyceraldehyde B. Proline C. Glycine D. All of these have an L or D configuration

glycine

41. Which of the following amino acids has a net charge of +1 at pH 4 and a net charge of 0 at pH 8? A. glu B. arg C. his D. tyr

his

23. Which amino acid takes on a positive charge when the R-group gains a proton? A. Glutamic Acid B. Histidine C. Glutamine D. Tyrosine E. Glycine

histidine

32. Which amino acid has a basic R group? A. Glutamic Acid B. Histidine C. Isoleucine D. Serine E. Tyrosine

histidine

76. Aspartame A. is a peptide derivative used as an artificial sweetener B. contains phenylalanine and arginine C. is extracted from asparagus D. all of these

is a peptide derivative used as an artificial sweetener

27. Which amino acid has the least polar R-group H? A. Glutamic Acid B. Histidine C. Isoleucine D. Serine E. Tyrosine

isoleucine

29. Which amino acid would likely be least water-soluble at pH 7.0 A. Histidine B. Isoleucine C. Isoleucine or Tyrosine, you cannot tell D. Serine E. Tyrosine

isoleucine or tyrosine, you cannot tell

33. Which of the following can be considered a unique characteristic of histidine? A. Its side chain is attached to the alpha carbon B. It has a basic side chain C. It has a side chain that is chemically basic but has an acidic pKa D. It is technically an "imino" acid

it has a side chain that is chemically basic but has an acidic pKa

68. The peptide bond A. is formed by elimination of water between two amino groups in an amindo acid B. limits the possible orientations of the peptide backbone in a protein C. has acidic and basic characteristics D. all of these

limits the possible orientations of the peptide backbone in a protein

20. Which group consists only of amino acids with basic side chains? A. leucine and lysine B. arginine and leucine C. lysine and arginine D. arginine and isoleucine

lysine and arginine

73. An inhibitor of this type of enzyme will likely act as an antidepressant: A. Decarboxylases B. Hydrolases C. Monoamine Oxidases D. Exopeptidases E. Inhibiting any of these enzymes can have an antidepressant effect

monoamine oxidases

45. What is the predominant form of the amino acid abbreviated E at pH 7? A. positive B. neutral C. negative

negative

44. What is the predominant form of the amino acid abbreviated val at pH 7? A. positive B. neutral C. negative

neutral

38. The pKa values of the amino groups of common amino acids A. occur at very low pH values B. occur in a range from pH 9 to pH 11 C. all occur at pH 8 D. all occur above pH 12

occur in a range from pH 9 to pH 11

7. Which of the following is an amino acid not found in proteins? A. asparagine B. ornithine C. isoleucine D. proline

ornithine

36. The pKa values of the alpha carboxyl groups of common amino acids are around A. pH 2 B. pH 5 C. pH 7 D. pH 9

pH 2

39. The isoelectric pH of glycine is closest to A. pH 4 B. pH 6 C. pH 8 D. pH 10

pH 6

72. Which type of reaction is not important in the creation and regulation of neurotransmitters? A. Decarboxylases B. Hydroxylases C. Monoamine Oxidases D. Peptidases E. All of these are important in the metabolism of neurotransmitters.

peptidases

43. What is the predominant form of the amino acid abbreviated R at pH 7? A. positive B. neutral C. negative

positive

26. Which amino acid has a polar, non-ionic R-group A. Glutamic Acid B. Histidine C. Isoleucine D. Serine E. Tyrosine

serine

71. Which amino acid is not a precursor to a neurotransmitter? A. Glutamic Acid B. Phenylalanine C. Serine D. Tryptophan E. Tyrosine

serine

13. Which group consists only of amino acids with polar side chains? A. serine, threonine, and leucine B. serine, threonine, and cysteine C. serine, threonine, and valine D. serine, threonine, and isoleucine

serine, threonine, cysteine

2. The side chain groups of amino acids are bonded to which carbon? A. The a-carbon. B. The b-carbon. C. The carbonyl carbon. D. Different amino acids have their side chains attached to different carbons

the a-carbon

66. Which groups of a pair of amino acids must react to form a peptide bond? A. the two carboxyls B. the two aminos C. the two R-groups D. the carboxyl of one and the amino of the other

the carboxyl of one and the amino of the other

30. Which of the following is not considered an uncommon amino acid? A. thyroxine B. Hydroxylysine C. Hydroxyproline D. Tryptophan

tryptophan

31. Which statement is true about the classification of amino acids? A. Alanine and valine are basic amino acids. B. Lysine and arginine are acidic amino acids. C. Glutamic acid and asparagine are hydrophobic amino acids. D. Tryptophan and phenylalanine are aromatic amino acids. E. Methionine and cysteine are hydroxyl-containing amino acids.

tryptophan and phenylalanine are aromatic amino acids

11. Which amino acid has a benzene-like ring? A. Glutamic Acid B. Histidine C. Isoleucine D. Serine E. Tyrosine

tyrosine

24. Given the R-groups in the peptide, ALA-GLN-ARG-SER-HIS, it would likely be: A. Very water soluble B. Somewhat water soluble C. Not very water soluble D. Not soluble at all E. You cannot tell from the sequence

very water soluble