sample exam sample-exam-final.pdf - CHEM 239U Spring 1997...

CHEM 239U
Spring, 1997 FINAL EXAM Name .
Prof. Sasaki
175 points TOTAL Good Luck!
Note: Only answers in the box will be graded.
________________________________________________________________________
1. (35) The following structure is drawn in an unconventional manner.
CH
2
CH
COOH
N
H
O
CH
N
H
C
O
CH
2
NH
CH
2
CH
2
C
O
NH
2
HOOC
peptide
(a) Label the N-terminus and the C-terminus.
(b) Circle all peptide bonds.
(c) The following reaction was carried out with the above peptide 1 . Draw the structures
of the products.
C
2
1
peptide 1
F
NO
2
NO
2
6N HCl
110•C
24hrs
products

CHEM 239U page 2 Name .
2. (35) (a) Draw the full structure of a three-residue segment of DNA with the following
sequence. (3')-G-C-A-(5')
(b) Retrovirus like HIV I, the pathogen responsible for AIDS, incorporate an RNA template that is
copied into DNA during infection. The reverse transcriptase enzyme that copies RNA into DNA
is relatively nonselective and error-prone, leading a high mutation rate. Its lack of selectivity is
exploited by the anti-HIV drug AZT (3'-azido-2',3'-dideoxythymidine), which becomes