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MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Which of the following is the cyclic hemiacetal formed from 4-hydroxyheptanal?
A) I
B) II
C) III
D) IV
2) Name the following structure.
A)
B)
C)
D)
E)
1)
E) V
2)
starch
amylose
amylopectin
lactose
cellulose
1
3) Which of the following is methyl- -D-glucoside?
A) I
B) II
C) III
3)
D) IV
E) V
4) Which monosaccharides are formed in the Kiliani-Fischer synthesis starting with D-xylose?
A)
B)
C)
D)
E)
4)
D-ribose and D-arabinose
D-glucose and D-mannose
D-galactose and D-talose
D-allose and D-altrose
D-gulose and D-idose
5) An aqueous solution of glucose behaves as an aldehyde because:
A) it can be oxidized with periodic acid.
B) glucose is actually a cyclic aldehyde.
C) its cyclic hemiacetal, the predominant form, is in equilibrium with the free aldehyde form.
D) it is a ketone, but is in equilibrium with the aldehyde form.
E) it is hydrolyzed by water to the free aldehyde.
2
5)
6) Give the major product(s) for the following reaction.
A) no reaction
B)
C)
D)
3
6)
E)
7) When D-threose is treated with NaBH4 ,:
A) an optically active alditol is produced.
B) a 70:30 mixture of enantiomeric alditols results.
C) a 50:50 mixture of enantiomeric alditols results.
D) a meso alditol is produced.
E) the product mixture contains two diastereomeric alditols.
7)
8) Which of the following statements regarding methyl- -L-glucopyranoside is correct?
A) This glycoside will be hydrolyzed to the cyclic hemiacetal in dilute aqueous acid.
B) This glycoside will undergo no reaction when treated with excess CH3 I/Ag2 O.
C) This glycoside undergoes mutorotation in aqueous base.
D) This glycoside will readily undergo Kiliani-Fischer chain elongation.
E) This glycoside is a reducing sugar.
8)
9) When two aldohexoses yield the same osazone upon treatment with phenylhydrazine, then
they are ________.
A) epimeric at C-3
B) epimeric at C-2
C) both necessarily D-sugars
D) epimeric at C-5
E) enantiomeric
9)
10) Which of the following corresponds to the definition of an aldopentose?
I. It is a monosaccharide.
II. It contains a CHO group
III. It is a disaccharide.
IV. It is an oligosaccharide.
A) II and III
B) I and III
C) I and II
D) I and IV
E) I, II, and III
4
10)
11) When a monosaccharide reacts to give the pyranose form from its open-chain form, how
many distinct pyranose forms are possible?
A) 2
B) 2 n, where n is the number of carbons present
C) 4n + 2, where n is the number of carbons present
D) 1
E) 4
11)
12) Give the name for the following compound.
12)
A)
B)
C)
D)
E)
4-O-(a-D-glucopyranosyl)-a-D-glucopyranose
4-O-(b-D-glucopyranosyl)- a-D-glucopyranose
4-O-(a-D-glucopyranosyl)-b-D-glucopyranose
4-O-(b-D-galactopyranosyl)-a-D-glucopyranose
4-O-(b-D-glucopyranosyl)- b-D-glucopyranose
13) In solution, glucose exists as:
A) an equilibrium mixture of the open-chain form and cyclic hemiacetal forms.
B) the open-chain form only.
C) the cyclic acetal form only.
D) an equilibrium mixture of the open-chain form and cyclic acetal forms.
E) the cyclic hemiacetal form only.
13)
14) Which of the following pairs of monosaccharides will form the same osazone when reacted
with phenylhydrazine?
A) D-glucose and L-glucose
B) D-glucose and D-gulose
C) D-glucose and D-fructose
D) D-glucose and D-galactose
E) D-glucose and D-allose
14)
5
15) Which of the following compounds is a nonreducing sugar?
A) I
B) II
C) III
15)
D) IV
16) Anomers of D-glucopyranose differ in their stereochemistry at:
A) C2.
B) C3.
C) C4.
D) C5.
E) V
E) C1.
17) Give the name for the following compound.
A)
B)
C)
D)
E)
16)
17)
b-cellobiose
a-lactose
b-maltose
a-cellobiose
a-maltose
18) How many chirality centers are there in an aldohexose?
A) 6
B) 3
C) 5
D) 4
19) Which of the following best represents the process of photosynthesis?
A) oxidation/reduction
B) elimination
C) disproportionation
D) exergonic
E) exothermic
6
E) 2
18)
19)
20) Give the major product(s) for the following reaction.
A) no reaction
B)
C)
D)
7
20)
E)
21) Which of the following is/are the product(s) obtained from the reduction of D-fructose?
A)
B)
C)
D) A and B
E) A and C
8
21)
22) Which of the following monosaccharides will form D-glucaric acid upon oxidation with nitric
acid?
A)
B)
C)
D) A and B
9
22)
E) A and C
23) Which of the following represents the general formula of a carbohydrate?
A) CnH2n-2
B) CnH2n+2
C) CnH2n
D) Cn(HO)n
E) Cn(H2 O)n
23)
24) Give the major product(s) for the following reaction.
24)
A) no reaction
B)
C)
10
D)
E)
25) How many chirality centers are there in a 2-ketohexose?
A) 3
B) 4
C) 2
26) Give the major product(s) for the following reaction.
A)
11
D) 5
E) 6
25)
26)
B)
C)
D)
E)
12
27) Calculate the isoelectric point for the following compound.
A) 6.91
B) 5.34
C) 3.22
27)
D) 5.93
E) 9.67
28) Which of the following amino acids has an aliphatic R group?
A) tyrosine
B) cysteine
C) serine
D) leucine
E) asparagine
28)
29) Which of the following is the first step in the determination of the primary structure of
proteins?
A) determining the number and kind of amino acids in the peptide
B) reducing the disulfide bridges in the protein
C) protecting the C-terminal of the peptide
D) hydrolyzing the protein with dilute acid
E) protecting the N-terminal of the peptide
29)
30) Give the product for the following reaction.
30)
A) valine
B) glycine
C) alanine
13
D) leucine
E) isoleucine
31) Which of the following amino acids has a side chain with an ionizable proton and can exist in
four different forms, depending on the pH of the solution?
A) I
B) II
C) III
D) IV
E) V
32) Which labeled bond in the following molecule is known as the peptide bond?
A) 1
B) 2
C) 3
D) 4
32)
E) 5
33) A decapeptide undergoes partial hydrolysis to give peptides whose amino acids are shown
below. Reaction of the decapeptide with Edman's reagent releases PTH-leu. What is the
sequence of the decapeptide?
(1) Pro, Ser
(2) Gly, Gly
(3) Met, Ala, Leu
(4) Gly, Ala
A)
B)
C)
D)
E)
(5) Glu, Ser, Val, Pro
(6) Glu, Pro, Gly
(7) Met, Leu
(8) His, Val
Leu-Met-Gly-Ala-Gly-Glu-Pro-Ser-Val-His
Leu-Met-Ala-Gly-Gly-Glu-Ser-Pro-Val-His
Leu-Met-Ala-Gly-Gly-Glu-Pro-Ser-His-Val
Leu-Ala-Met-Gly-Gly-Glu-Pro-Ser-Val-His
Leu-Met-Ala-Gly-Gly-Glu-Pro-Ser-Val-His
14
31)
33)
34) Name the following compound.
A)
B)
C)
D)
E)
34)
threonine
serine
methionine
asparagine
cysteine
35) Which of the following best represents the structure of an amino acid in basic solution (pH =
11)?
A)
35)
B)
C)
D)
E)
36) Give the product for the following reaction.
36)
15
A)
B)
C)
D)
E)
37) What is the product obtained from the mild oxidation of the thiol shown below?
37)
mild
2 R SH oxidation
A) R-S-R
B) R-S-S-R
C) R-S-OH
16
D) R-OO-R
E) R-OH
38) Which of the following amino acids will be closest to the origin when separated by thin-layer
chromatography?
A) I
B) II
C) III
D) IV
E) V
39) Which of the following is an L-amino acid?
A) I
B) II
38)
39)
C) III
D) IV
17
E) V
40) Name the peptide.
A)
B)
C)
D)
E)
40)
ala-val-leu-gln
ser-cys-phe-gly
ala-gly-phe-val
ser-cys-tyr-gly
phe-ala-val-leu
41) Which of the following is the quaternary structure of proteins concerned with?
A) sequence of amino acids in the peptide chain
B) conformation of the protein backbone
C) three-dimensional arrangement of all atoms in the protein
D) description of the way the peptide chains are arranged with respect to each other
E) location of the disulfide bridges in the peptide chain
41)
42) Which of the following protein structures does denaturation destroy?
A) secondary and tertiary structures
B) primary and secondary structures
C) tertiary and quaternary structures
D) secondary, tertiary, and quaternary structures
42)
43) Consider the two peptides shown below. Which of the following methods would be able to
distinguish between these two sequences?
43)
Ala-Met-Val-Leu-Gly-Gly-Phe-Glu-Arg-Val
and
Ala-Val-Gly-Glu-Val-Met-Leu-Gly-Arg-Phe
A)
B)
C)
D)
E)
complete hydrolysis of all peptide bonds
chymotrypsin digestion
one cycle of Edman's reagent
both A and B
none of the above
18
44) Identify the amino acid that is hydrolyzed by cyanogen bromide.
A)
B)
C)
D)
E)
44)
C-side of gly
C-side of phe
C-side of arg
C-side of met
N-side of met
45) Phenyl isothiocyanate (PITC) is commonly known as Edman's reagent. Edman's reagent is
widely used to identify which of the following?
A) the number and kind of amino acids in the protein
B) the disulfide bridges in the protein
C) the number of peptide bonds in the protein
D) C-terminal amino acid of the protein
E) N-terminal amino acid of the protein
45)
46) What is the pI of arginine? The structure and pKa values are shown below.
46)
A) 10.76
B) 5.61
C) 7.33
19
D) 7.90
E) 9.67
47) Which of the following amino acids will be retained longest in the column when separated by
cation-exchange chromatography?
A) I
B) II
C) III
D) IV
E) V
48) What is the pI of glycine? The structure and pKa values are shown below.
A) 7.26
B) 7.50
C) 3.63
D) 5.97
47)
48)
E) 11.94
49) What are enzymes?
A) saccharides that catalyze chemical reactions
B) unsaturated fats that catalyze chemical reactions
C) DNA molecules that catalyze chemical reactions
D) nucleic acids that catalyze chemical reactions
E) proteins that catalyze chemical reactions
49)
50) In peptide synthesis, give the use of dicyclohexylcarbodiimide.
A) activates the carboxyl group of an amino acid
B) activates the amino group of an amino acid
C) removes the protecting group on the N-terminal amino acid
D) protects the carboxyl group of an amino acid
E) protects the amino group of an amino acid
50)
20
51) Give the pH at which histidine exists in the following form.
A) 4
B) 12
C) 14
51)
D) 0
21
E) 8