580.221_Exam 3_2016
Name: _____________________________________
1
Molecules and Cells: Exam 3
Wednesday, December 14, 2016
You are reminded that you are under an honor code at Johns Hopkins and all work on this exam
is expected to be entirely your own. You may not use any electronics other than the BME
calculators distributed during the exam. You may not use any notes.
Read the questions carefully. Most answers require only a very brief explanation. Phrases or
bullet points are fine  you do not need to use full sentences.
Show all work/calculations for any problems.
Clearly indicate the answer to each question. This is a three hour exam so you should have plenty
of time to answer each of the questions.
This exam has questions from three faculty:
Faculty
Points
Questions/pages
Dr. Haase
20
12 questions/6 pages
Dr. Yarema
40
3 multipart questions/ 10 pages
Dr. MacGabhann
40
9 questions/14 pages
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580.221_Exam 3_2016
Name: _____________________________________
2
Helpful Equations:
Assume R is 1.98 x 10
3
kcal/(K mole), T is 310 K
RT = 0.616 kcal/mol,
and F=23.06 kcal volt
1
mol
1
for all problems unless otherwise specified
𝐾𝑒𝑞 = 𝑒
−∆𝐺°/𝑅𝑇
= 10
−∆𝐺°/1.36
eq
o
K
RT
G
ln
]
tan
[
]
[
ln
ts
reac
products
RT
G
G
o
This section for grading:
Faculty
Points
Score
Dr. Haase
20
Dr. Yarema
40
Dr. MacGabhann
40




nFE
G
m

]
[
]
[
ln



in
out
c
X
X
RT
G
580.221_Exam 3_2016
Name: _____________________________________
Dr. Haase:
Multiple choice/short answer/short problem
–
20 pts total
1.
(5 pts total, 1 pt each part)
Consider the reaction:
A
i.
What is the
equilibrium constant
, Keq, for this reaction?
ii.
If the Gibbs free energy of A is less than the Gibbs free energy of B, which of the
following is true at equilibrium? (circle all that apply)
B
3
iv.
Now consider the reaction:
A
B
Start with [A]=[B] = 1M, and [C]=0.
Given that the Gibbs free energy of C is less than the Gibbs free energy of B.
Will [A] at equilibrium increase or decrease from your answer in part “ii”.
Explain:
C
iii.
Continuing with the situation from above, if [A]=[B] = 1M, which of the following
is/are true?
580.221_Exam 3_2016
Name: _____________________________________
v.
The Gibbs free energy for a reaction can become negative by:
4