CHEM 432 Midtern exam 1, 2 and 3 with complete solutions 2025/26.
KEY
NAME: _____________________________________________
CHEM 432
Spring 2025
MIDTERM EXAM I
February 4, 2025
This exam is closed book.
You are bound by the Honor Code.
Points as indicated for a total of 100.
Confirm your answers to the space provided.
The last three pages can be used as scratch paper and will not be graded.
,1. Name the overall metabolic pathways that build and degrade materials. What must be true
about how these pathways relate to one another? (3 points)
ANABOLIC – build 1 PT EACH
CATABOLIC - degrade
Must differ by at least one step.
2. Name three ways that enzyme facilitate chemical catalysis. State also how enzymes impact
the delta-G of a reaction. (4 points)
1 PT EACH
Promixity and Orientation
Reducing activation energy
Preferential transition state binding (or stabilizing transition state)
No change in Detla-G of a reaction.
3. Draw the equilibrium between the imine and enamine of a Schiff base. (5 points)
3PTS 2 PTS
4. Draw the complete structure of FAD. (8 points)
2
,5. Draw the mechanism for the 4th step in glycolysis, naming the enzyme, the substrate(s), and
the product(s). (12 points)
O
O
O O
O
O PLUS
5115
N CIRCLES
6. Draw the reaction catalyzed by lactate dehydrogenase at the level of detail provided in
lecture. (4 points)
7. Name the amino acid(s) that can be modified by O-linked and by N-linked sites of
glycosylation. (2 points)
O-linked: Serine, Threonine (S, T or Ser, Thr OK)
N-linked: Asparagine (N or Asn OK)
3
, 8. Draw the hexokinase mechanism at the level of detail provided in lecture, naming the
substrates and products, and indicating the transition state. (8 points)
ASP
To
1110 8 O ADP
t.IE f
o aop
Glucose
H H
ASP no
1 00 Hot ADP
10 ADP ro pro
t.EE
0
8 5
10
to HO ADP F TRANSITION
H STATE
GLUCOSE 6
PHOSPHATE
9. Draw the mechanism of the 9th step of glycolysis at the level of detail provided in lecture,
naming the enzyme, substrates, and products. (6 points)
DEHYDRATION REACTION ELIMCNAMON
MECHANISM
T
LNOLA.SE
Mg2tO PO MgZ
I e O
i
ofv o H OO H
2-Phosphoglycerate Ng
r
C
I
c
i
c H
f
Mg2 C
I
C d H
t off
ok
TBH
O
NHS H o
HiiH I c o
Hoyo LYS
I
Lys l Giv
Glo
Hao
I
PEP
Mg2
Mga o
f O
C
I
C C pepo Phosphoenolpyruvate
T o H
Mg2 µg2t
NHz HO
cao HzN H
y C O
Lys giv l
1
Lys Glu
ENZYME REGERATED
10. Draw the structure of a fatty acid denoted by 20:2cD11,15 (1 point)
MAXIM
4
KEY
NAME: _____________________________________________
CHEM 432
Spring 2025
MIDTERM EXAM I
February 4, 2025
This exam is closed book.
You are bound by the Honor Code.
Points as indicated for a total of 100.
Confirm your answers to the space provided.
The last three pages can be used as scratch paper and will not be graded.
,1. Name the overall metabolic pathways that build and degrade materials. What must be true
about how these pathways relate to one another? (3 points)
ANABOLIC – build 1 PT EACH
CATABOLIC - degrade
Must differ by at least one step.
2. Name three ways that enzyme facilitate chemical catalysis. State also how enzymes impact
the delta-G of a reaction. (4 points)
1 PT EACH
Promixity and Orientation
Reducing activation energy
Preferential transition state binding (or stabilizing transition state)
No change in Detla-G of a reaction.
3. Draw the equilibrium between the imine and enamine of a Schiff base. (5 points)
3PTS 2 PTS
4. Draw the complete structure of FAD. (8 points)
2
,5. Draw the mechanism for the 4th step in glycolysis, naming the enzyme, the substrate(s), and
the product(s). (12 points)
O
O
O O
O
O PLUS
5115
N CIRCLES
6. Draw the reaction catalyzed by lactate dehydrogenase at the level of detail provided in
lecture. (4 points)
7. Name the amino acid(s) that can be modified by O-linked and by N-linked sites of
glycosylation. (2 points)
O-linked: Serine, Threonine (S, T or Ser, Thr OK)
N-linked: Asparagine (N or Asn OK)
3
, 8. Draw the hexokinase mechanism at the level of detail provided in lecture, naming the
substrates and products, and indicating the transition state. (8 points)
ASP
To
1110 8 O ADP
t.IE f
o aop
Glucose
H H
ASP no
1 00 Hot ADP
10 ADP ro pro
t.EE
0
8 5
10
to HO ADP F TRANSITION
H STATE
GLUCOSE 6
PHOSPHATE
9. Draw the mechanism of the 9th step of glycolysis at the level of detail provided in lecture,
naming the enzyme, substrates, and products. (6 points)
DEHYDRATION REACTION ELIMCNAMON
MECHANISM
T
LNOLA.SE
Mg2tO PO MgZ
I e O
i
ofv o H OO H
2-Phosphoglycerate Ng
r
C
I
c
i
c H
f
Mg2 C
I
C d H
t off
ok
TBH
O
NHS H o
HiiH I c o
Hoyo LYS
I
Lys l Giv
Glo
Hao
I
PEP
Mg2
Mga o
f O
C
I
C C pepo Phosphoenolpyruvate
T o H
Mg2 µg2t
NHz HO
cao HzN H
y C O
Lys giv l
1
Lys Glu
ENZYME REGERATED
10. Draw the structure of a fatty acid denoted by 20:2cD11,15 (1 point)
MAXIM
4
