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EXAMINATION PAPER
Exam in:
Kje-2002 Molecular Structural Chemistry
Date:
Friday 29. November 2013
Time:
Kl 15:00 – 19:00
Place:
Åsgårdsveien 9
Approved aids:
Calculator
The exam contains 6 pages included this cover page
Contact person: Ingar Leiros
Phone: 95966895 / 77644064
Question 1.
Multiple choices. Select the correct answer to the statements.
(Answer in a form like this: 1a), 2d), etc.)
1. The three-dimensional structure of macromolecules is formed and maintained
primarily through noncovalent interactions. Which of the following is not considered a
noncovalent interaction?
a)
hydrogen bonds
b)
van der Waals interactions
c)
disulfide bonds
d) ion-pair interaction (salt bridges)
2. Which of the following amino acids is the smallest of all amino acids?
a)
Glycine
b)
Histidine
c)
Valine
d) Lysine
3. In an α-helix, the R-groups on the amino acid residues ___________.
a)
are found on the outside of the helix spiral
b)
generate the hydrogen bonds that form the helix
c)
stack the interior of the helix
d) alternate between the outside and the inside of the helix
4. Peptide bonds link _________.
a)
fats
b)
amino acids
c)
nucleic acids
d) carbohydrates
5. This stabilizes the secondary structure of proteins.
a)
peptide bonds
b)
psi bonds
c)
phi bonds
d) hydrogen bonds
6. Amino acids that an organism cannot synthesize on its own are called……
a)
essential amino acids
b)
basic amino acids
c)
acidic amino acids
d) forced amino acids
Continued on next page.
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7. The amino acids sequence of a protein is the ____________ structure.
a)
primary
b)
secondary
c)
tertiary
d) quaternary
8. Proteins are composed of monomer units. These units are called….
a)
peptide bonds
b)
functional groups
c)
amino acids
d) thiols
9. The two strands of double-stranded DNA are interconnected by
a)
peptide bonds
b)
glycosidic bonds
c)
hydrogen bonds
d) phosphodiester bonds
10. What is the main carbohydrate storage form in animals?
a)
cellulose
b)
protein
c)
starch
d) glycogen
11. Of what is a triglyceride composed?
a)
One glycerol with 3 fatty acids
b)
3 glycerides
c)
3 glycerols and one fatty acid
d) 3 fatty acids
12. In nucleic acids, the purine bases are ….
a)
uracil and thymine
b)
cytosine and guanine
c)
thymine and cytosine
d) adenine and guanine
13. What type of macromolecule carries out catalysis in biological systems?
a)
proteins called enzymes
b)
nucleic acids called DNA
c)
carbohydrates called sugars
d) lipids called steroids
Continued on next page.
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14. Glucose is a …….
a)
protein
b)
disaccharide
c)
nucleic acid
d) monosaccharide
15. Which of the following bases is found in DNA but is not found in RNA?
a)
adenine
b)
cytosine
c)
thymine
d) uracil
16. Fats and oils are composed of what two groups of molecules?
a)
starch and sugar
b)
glucose and fructose
c)
fatty acids and glycerol
d) water and cellulose
17. Viruses possess genetic material composed of __________.
a)
protein only
b)
RNA only
c)
DNA and RNA together
d) DNA or RNA
18. Viruses that infect bacteria are called ___________.
a)
bacteriophages
b)
virions
c)
polyhedral
d) hepadnaviridae
Continued on next page.
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Question 2.
A Ramachandran plot is outlined:
a)
What angles are plotted along the x-axis and y-axis?
Explain where these angles originate from.
b)
What do the framed areas in the Ramachandran plot represent?
c)
Which amino acids are generally not taken into account in the Ramachandran
plot?
Explain why.
d)
How can amino acids be classified with respect to properties?
Give examples of such properties.
e)
What functions can proteins have?
Describe briefly as many of these as possible.
Continued on next page.
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Question 3.
a)
Some important terms in Nuclear Magnetic Resonance (NMR) are:
i) spin
ii) spectrum
iii) chemical shifts
iv) internal standard.
Explain briefly each of the terms.
b)
Deuteration is commonly used in Neutron Diffraction, but can also be used in
Nuclear Magnetic Resonance (NMR).
Describe briefly two main applications for deuteration when studying proteins
with NMR.
c)
What is the difference between spin coupling and Nuclear Overhauser Effect
(NOE)?
Question 4.
a)
Give an overview of the most common method for crystallising macromolecules.
b)
Describe briefly the steps taken in order to solve the three-dimensional structure
of a protein using X-ray crystallography. Assume that you are starting with a
crystal.
c)
What is a big technical drawback of X-ray crystallography compared to NMR?
Good luck!
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