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Chemistry 27 13 Name: ________________________
Biochemistry Student Number: _______________
Winter 2018
Midterm Exam # 3
Answer all questions on the test. Each multiple choice question has a value of two points and must be
answered in pencil on the bubble sheet provided. The value for each short answer question is given with
the questions.
The final page of the exam has equations and other relevant information. Feel free to remove this page,
but the rest of the midterm and the bubble sheet must be submitted to receive marks for all questions.
Programmable calculators are not allowed.
1 18
1
H
1.00 8
2 13 14 15 16 17
2
He
3
Li
4
Be
5
B
6
C
7
N
8
O
9
F
10
Ne
11
Na
22.9 9
12
Mg
3 4 5 6 7 8 9 10 11 12
13
Al
14
Si
15
P
16
S
17
Cl
18
Ar
19
K
20
Ca
21
Sc
22
Ti
23
V
24
Cr
25
Mn
26
Fe
27
Co
28
Ni
29
Cu
30
Zn
31
Ga
32
Ge
33
As
34
Se
35
Br
36
Kr
37
Rb
38
Sr
39
Y
40
Zr
41
Nb
42
Mo
43
Tc
(98)
44
Ru
45
Rh
46
Pd
47
Ag
48
Cd
49
In
50
Sn
51
Sb
52
Te
53
I
54
Xe
55
Cs
56
Ba
57
La
72
Hf
73
Ta
74
W
75
Re
76
Os
77
Ir
78
Pt
79
Au
80
Hg
81
Tl
82
Pb
83
Bi
84
Po
(209)
85
At
(210)
86
Rn
(222)
87
Fr
(223)
88
Ra
89
Ac
104
Rf
(265)
105
Db
(268)
106
Sg
(271)
107
Bh
(270)
108
Hs
(277)
109
Mt
(276)
110
Ds
(281)
111
Rg
(280)
112
Cn
(285)
113
Nh
(284)
114
Fl
(289)
115
Mc
(288)
116
Lv
(293)
117
Ts
(294)
118
Og
(294)
Multiple Choice / 60
Structure Drawing / 20
Bonus /
Total / 75
Question 1
Which of the following is not a function of proteins?
a. catalysis
b. energy storage
c. regulation
d. structure
e. transport
Question 2
Which of the following is not an example of a conjugated protein?
a. glycoproteins
b. lipoproteins
c. metalloproteins
d. peptoproteins
e. phosphoproteins
Question 3
Which of the following does not describe a globular protein?
a. generally function in structure and support roles
b. hemoglobin is an example
c. often function as enzymes or transport proteins
d. peptide chains folded into spherical shapes
e. water soluble
Question 4
The amino acid sequence of a polypeptide is referred to as its ________structure.
a. primary
b. secondary
c. tertiary
d. quaternary
e. peptide
Question 5
When an amino acid sequence changes due to the substitution of a chemically different amino acid
without change in the protein's function, the position is called:
a. conservative
b. consistent
c. invariant
d. steady-state
e. variable
Question 11
Which pair of amino acids can form hydrogen bonds between their side chains at physiological pH?
a. serine and valine
b. alanine and threonine
c. lysine and histidine
d. aspartate and glutamate
e. glycine and leucine
Question 12
Invariant amino acids in a protein are presumed:
a. to be unimportant in the structure and function of the protein
b. to be essential to the structure and function of the protein
c. always to occur at the beginning of the amino acid sequence of a protein
d. always to occur at the end of the amino acid sequence of a protein
e. to be part of the prosthetic group
Question 13
Reducing agents denature proteins by disrupting which of the following?
a. hydrogen bonds
b. disulfide bridges
c. hydrophobic interactions
d. salt bridges
e. water bridges
Question 14
Organic solvents denature proteins by disrupting which if the following?
a. hydrogen bonds
b. disulfide bridges
c. hydrophobic interactions
d. salt bridges
e. water bridges
Question 15
What type of process is the denaturation of egg albumin by heating?
a. equilibrium
b. exothermic
c. irreversible
d. osmotic
e. reversible
Question 16
Collagen is classified as which of the following types of protein?
a. enzyme
b. structural
c. movement
d. defence
e. regulatory
Question 17
Aldol condensation reactions occur between which of the following functional groups?
a. alcohol + alcohol
b. alcohol + aldehyde
c. alcohol + alkene
d. aldehyde + aldehyde
e. aldehyde + alkene
Question 18
Which type of chromatography can separate proteins based on enzyme-substrate binding?
a. affinity chromatography
b. ion-exchange chromatography
c. size-exclusion chromatography
d. thin-layer chromatography
e. all types of chromatography
Question 19
In gel-filtration chromatography:
a. large proteins elute first
b. negatively charged proteins elute first
c. non-polar proteins elute first
d. positively charged proteins elute first
e. small proteins elute first
Question 20
Catalysts are effective because they:
a. decrease the activation energy of a reaction
b. decrease the rate of the reverse reaction
c. increase the energy released during a reaction
d. increase the entropy (disorder) of the products
e. increase the temperature of the reaction mixture
Question 26
The steady state assumption states that if:
k 1
= the rate constant for ES formation
k 2
= the rate constant for ES dissociation
k 3
= the rate constant for product formation
a. k 2
is negligible compared to k 3
b. the rate of formation of ES is equal to the rate of its degradation over the course of
the reaction
c. the rate of formation of ES exceeds the rate of degradation over the course of the
reaction
d. k 3
is negligible compared to k 2
e. product concentration at the beginning of the reaction is low
Question 27
Consider the following diagram. What constitutes the activation energy for the forward reaction?
a. C – A
b. C – E
c. E – A
d. A – C
e. A – E
Question 28
In irreversible inhibition, increasing the concentration of substrate:
a. decreases the reaction rate
b. double the reaction rate
c. has no effect on the reaction rate
d. overcomes the inhibition, increasing the reaction rate up to ½V max
e. overcomes the inhibition, increasing the reaction rate up to V max
Question 29
In the Lineweaver-Burk double reciprocal plot the vertical intercept is equal to?
a. 1/[S]
b. 1/V
c. K m
/V
max
d. 1/V max
e. – 1/ K m
Question 30
Which of the following amino acids is capable of acting as a general acid or general base at
physiological pH?
a. glycine
b. histidine
c. proline
d. tyrosine
e. tryptophan
Question 31
What type of enzyme catalyzes the following reaction?
a. hydrolase
b. lyase
c. ligase
d. oxidoreductase
e. transferase
Question 32
What type of enzyme catalyzes the following reaction?
a. isomerase
b. lyase
c. ligase
d. oxidoreductase
e. transferase
Question 36
The kinetics for hydrolysis reactions in biological systems are assumed to follow:
a. zero-order reactions
b. first-order reactions
c. second-order reactions
d. pseudo-first-order reactions
e. pseudo-second-order reactions
Question 37
Which of the following amino acids cannot actively participate in a catalytic site?
a. serine
b. threonine
c. tyrosine
d. glycine
e. glutamine
Question 38
Which of the following is not an important metal in biological systems
a. Na
b. K
c. Mg
2+
d. Cu
2+
e. Al
3 +
Question 39
Consider the following reaction data for the reaction of pyruvate with ADP and phosphate (P i
Exp
Concentration (M)
Rate (M·s
Pyruvate ADP P i
1 0.1 0.1 0.1 8.0 × 10
2 0.2 0.1 0.1 1.6 × 10
3 0.2 0.2 0.1 3.2 × 10
4 0.1 0.1 0.2 3.2 × 10
The reaction is ________ overall.
a. zero-order
b. first-order
c. second-order
d. third-order
e. fourth-order
1. 6 × 10
− 3
8. 0 × 10
− 4
𝑘[ 0. 2 ]
𝑥
[ 0. 1 ]
𝑦
[ 0. 1 ]
𝑧
𝑘[ 0. 1 ]
𝑥
[ 0. 1 ]
𝑦
[ 0. 1 ]
𝑧
𝑥
𝑥
log 2
log 2
3. 2 × 10
− 3
1. 6 × 10
− 3
𝑘[ 0. 2 ]
𝑥
[ 0. 2 ]
𝑦
[ 0. 1 ]
𝑧
𝑘[ 0. 2 ]
𝑥
[ 0. 1 ]
𝑦
[ 0. 1 ]
𝑧
𝑦
𝑦
log 2
log 2
𝑖
3. 2 × 10
− 3
8. 0 × 10
− 4
𝑘[ 0. 1 ]
𝑥
[ 0. 1 ]
𝑦
[ 0. 2 ]
𝑧
𝑘[ 0. 1 ]
𝑥
[ 0. 1 ]
𝑦
[ 0. 1 ]
𝑧
𝑧
𝑧
log 4
log 2
Question 40
Medical isotopes are a Canadian innovation. Technetium-99, the most commonly used medical
radioisotope in the world, decomposes in a first-order process with a half-life of 6.01 h. How long
before 95% of the radioactive technetium has decayed in a patient?
a. 0.445 h
b. 0.498 h
c. 5.71 h
d. 2 2.8 h
e. 26.0 h
1
2
⁄
ln 2
ln 2
1
2
⁄
ln 2
− 1
[
]
𝑡
= 0. 05 ×
[
]
0
ln
[
]
𝑡
[𝑆]
0
ln
0. 05 [𝑆]
0
[𝑆]
0
= ln 0. 05 = −( 0. 1153 ℎ
− 1
ln 0. 05
− 1
Question 41 ( 1 5 points)
Draw the primary structure of the amino acid (indicated by its abbreviation) at physiological pH.
Bonus Question (6 points)
The velocity of an enzyme-catalyzed reaction that follows Michaelis-Menten kinetics was measured at
several substrate concentrations (shown below). Calculate 𝐾 𝑚
and V
𝑚𝑎𝑥
[S] (μM) 𝑣
0
(mM∙s
) 1/[S] 1/𝑣
0
𝑚
𝑚𝑎𝑥
𝑚𝑎𝑥
𝑚𝑎𝑥
− 1
𝑚
𝑚𝑎𝑥
𝑚
𝑚
OR from the 𝑥 − 𝑖𝑛𝑡𝑒𝑟𝑐𝑒𝑝𝑡
𝑚
𝑚
