Chem 128 – Introduction to Chemical Biology
Midterm 2
Take a deep breath. Ok. Exhale and relax.
n Put your NAME and UCI ID number on the cover page, and complete the section below for your seat
number and signature.
n For maximum credit…
i) draw structures neatly
ii) show all elementary steps of reaction mechanisms
iii) clearly indicate where arrows begin and where arrows end.
n Now, turn the exam over and count to make sure that you have a complete examination. (There are 6
pages to the examination including the coversheet.)
n No electronic devices, textbooks, or notes can be used.
n Read through the exam before you begin. It will help you to budget your time.
n You may use the back of each page as scratch paper, but clearly label what you want to have graded.
• Your signature below indicates that you agree to abide by all U.C. Irvine regulations
concerning academic honesty. Your exam will not be graded unless this section is completed
m
er as
co
Seat
eH w
Number:_______KEY_______________________
o.
rs e
Signature:______KEY_______________________
ou urc
___
o
aC s
vi y re
ed d
ar stu
is
PROBLEM POSSIBLE SCORE
Th
POINTS
1 15
2 12
sh
3 30
4 23
5 20
Bonus 5
Total 105 KEY
1
This study source was downloaded by 100000763811389 from CourseHero.com on 04-29-2021 03:56:22 GMT -05:00
https://www.coursehero.com/file/28966382/Midterm-2-2014-KEYpdf/
, Chem 128 – Introduction to Chemical Biology
1(15 pts.) 1A. Fill in the blanks with the correct word or words below. From p. 143 in the textbook.
With such a diverse portfolio of functions, random synthesis of different mRNAs would quickly
prove disastrous for the cell. Instead, transcription by _RNA polymerase_______ is a tightly regulated
event, dependent on the orchestration of __DNA sequences_________and__transcription factors________.
Transcriptional regulation is driven by (1) ___growth OR cell division OR reproduction OR
development_____ and (2) __metabolism or nutrient intake OR excretion of waste________.
1B. Answer the following question using a short, complete sentence.
Under what circumstances can one borrow language from a journal article?
The borrowed language must be offset from the main text using quotation marks or indentation, and the
source must be cited.
m
er as
co
eH w
2. (12 pts) Suggest a plausible arrow pushing reaction mechanism for the following reduction of disulfide
o.
rs e
bonds using a phosphine reagent. Hint: A phosphine (R3P) can act as a nucleophile.
Cys
ou urc
R3P + S S R3P=O + 2 Cys-SH
Cys H2O
o
aC s
vi y re
OH
H
Cys Cys
R 3P: + S S S -:
S Cys-SH
Cys R 3P + Cys
ed d
Cys-SH
ar stu
H 2O :
is
Cys Cys OH
S H
S R 3P=O
Th
:OH 2 R 3P -:
R 3P S
O+ O :OH 2 Cys
H H H
sh
2
This study source was downloaded by 100000763811389 from CourseHero.com on 04-29-2021 03:56:22 GMT -05:00
https://www.coursehero.com/file/28966382/Midterm-2-2014-KEYpdf/
Midterm 2
Take a deep breath. Ok. Exhale and relax.
n Put your NAME and UCI ID number on the cover page, and complete the section below for your seat
number and signature.
n For maximum credit…
i) draw structures neatly
ii) show all elementary steps of reaction mechanisms
iii) clearly indicate where arrows begin and where arrows end.
n Now, turn the exam over and count to make sure that you have a complete examination. (There are 6
pages to the examination including the coversheet.)
n No electronic devices, textbooks, or notes can be used.
n Read through the exam before you begin. It will help you to budget your time.
n You may use the back of each page as scratch paper, but clearly label what you want to have graded.
• Your signature below indicates that you agree to abide by all U.C. Irvine regulations
concerning academic honesty. Your exam will not be graded unless this section is completed
m
er as
co
Seat
eH w
Number:_______KEY_______________________
o.
rs e
Signature:______KEY_______________________
ou urc
___
o
aC s
vi y re
ed d
ar stu
is
PROBLEM POSSIBLE SCORE
Th
POINTS
1 15
2 12
sh
3 30
4 23
5 20
Bonus 5
Total 105 KEY
1
This study source was downloaded by 100000763811389 from CourseHero.com on 04-29-2021 03:56:22 GMT -05:00
https://www.coursehero.com/file/28966382/Midterm-2-2014-KEYpdf/
, Chem 128 – Introduction to Chemical Biology
1(15 pts.) 1A. Fill in the blanks with the correct word or words below. From p. 143 in the textbook.
With such a diverse portfolio of functions, random synthesis of different mRNAs would quickly
prove disastrous for the cell. Instead, transcription by _RNA polymerase_______ is a tightly regulated
event, dependent on the orchestration of __DNA sequences_________and__transcription factors________.
Transcriptional regulation is driven by (1) ___growth OR cell division OR reproduction OR
development_____ and (2) __metabolism or nutrient intake OR excretion of waste________.
1B. Answer the following question using a short, complete sentence.
Under what circumstances can one borrow language from a journal article?
The borrowed language must be offset from the main text using quotation marks or indentation, and the
source must be cited.
m
er as
co
eH w
2. (12 pts) Suggest a plausible arrow pushing reaction mechanism for the following reduction of disulfide
o.
rs e
bonds using a phosphine reagent. Hint: A phosphine (R3P) can act as a nucleophile.
Cys
ou urc
R3P + S S R3P=O + 2 Cys-SH
Cys H2O
o
aC s
vi y re
OH
H
Cys Cys
R 3P: + S S S -:
S Cys-SH
Cys R 3P + Cys
ed d
Cys-SH
ar stu
H 2O :
is
Cys Cys OH
S H
S R 3P=O
Th
:OH 2 R 3P -:
R 3P S
O+ O :OH 2 Cys
H H H
sh
2
This study source was downloaded by 100000763811389 from CourseHero.com on 04-29-2021 03:56:22 GMT -05:00
https://www.coursehero.com/file/28966382/Midterm-2-2014-KEYpdf/
