01:694:301 Lecture 14: Problem Set #11_Nucleic Acids_2020Exam
DepartmentMolecular Biology and Biochemistry
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Practice and Recitation questions for Ch. 10-11
(Recitation for Wednesday 22 April will only address questions and problems for
material already covered by Monday 20 April; questions and problems not yet addressed
by that time will be covered the following week)
Recommended problems from Garrett & Grisham (for your own practice, only to
be discussed in Recitation if something isn’t clear):
Ch. 10: #1-14 are all good problems, and 19 and 20 are good non-quantitative thought
5.The Base Sequence in the Two Polynucleotide Chains of a DNA Double Helix is
Adhering to the convention of writing nucleotide sequences in the 5’→3’ direction, what
is the nucleotide sequence of the DNA strand that is complementary to
3’ – TAGCGTTGACAGTGAT – 5’
Flip it since they want it 5’ → 3’ direction
5’ – TAGTGACAGTTCGGAT-3’
6.The relationship Between the Nucleotide Sequence of an mrNA and the DNA
Strand from Which it is Transcribed
mRNAs are synthesized by RNA polymerases that read along a DNA template strand in
the 3’→ 5’ direction, polymerizing ribonucleotides in the 5’→3’ direction (see Figure
10.20). Give the nucleotide sequence (5’→3’) of the DNA template strand from which
the following mRNA segment was transcribed: 5’-UAG UGACAGUUGC GAU-3’
3’ – ATCACTGTCAACGCTA – 5’
• Usually it would be 3’ → 5’, but reverse it since they want it 5’→ 3’
5’- ATCGCAACTGTCACTA – 3’
13. The Properties That Carbohydrates Contribute to Nucleosides, Nucleotides, and
Nucleic Acids A carbohydrate group is an integral part of a nucleoside.
a.What advantage does the carbohydrate provide? Polynucleotides are formed
through formation of a sugar–phosphate backbone.
Increases the water solubility of the base.
b.Why might ribose be preferable for this backbone instead of glucose?
Ribose has fewer OH groups, and less likely to undergo unwanted side reactions.
c.Why might 2-deoxyribose be preferable to ribose in some situations?
The absence of the OH in 2-deoxyribose leads to a backbone that is more stable because
it is more resistant to alkaline hydrolysis.
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