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Final Exam
Chem 103, Winter 2006
Name _________________________________
1. (11 points) Consider the monosaccharide fructose.
a) Draw the Fischer projection for L-fructose.
b) What is the isomeric relationship between D-fructose and D-glucose?
Enantiomers
Diastereomers
Constitutional Isomers
c) What is the isomeric relationship between D-fructose and L-fructose?
Enantiomers
Diastereomers
Constitutional Isomers
d) Can we metabolize L-fructose? Why, or why not?
f) Is fructose a reducing sugar? Explain why, or why not, and if yes, draw the product
for the reaction of D-fructose with Tollens’ reagent.
g) Draw the product for the reaction of -L-fructose with methanol and acid catalyst.
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2. (5 points) Sucrose is the most abundant carbohydrate in the world.
a) Draw the structure of sucrose.
b) What type of glycosidic bond does sucrose have?
c) Is sucrose a reducing sugar? Why, or why not?
3. (3 points) Cellulose and amylose both come from plants.
a) What is the main structural difference between cellulose and amylose?
b) Iodine forms a dark blue complex with amylose, but not with cellulose. Explain
why.
4. (2 points) Explain why trans fatty acids have higher melting points (are more solid at
room temp.) than fatty acids.
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5. (2 points) Explain how an NSAID, such as ibuprofen, reduces pain and swelling
from an injury.
6. (5 points) Triolein, the main triacylglycerol in olive oil, contains only one type of
fatty acid, oleic acid: CH3(CH2)7CH=CH(CH2)7CH3.
a) Draw the structure of triolein.
b) Write the products for the oxidation of triolein.
c) Write the products for the saponification of triolein.
7. (3 points) Which three types of lipids contain the steroid nucleus?
8. (2 points) What is HDL, and why is it considered “good”?
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9. (2 points) What are the roles of each of the following in cell membranes?
a) glycosphingolipids
c) cholesterol
10. (1 point) Which one of the polar (neutral) amino acids is not able to participate in
H-bonding?
11. (4 points) Draw the four forms of aspartic acid and rank them in order of
decreasing pH (most basic solution to most acidic solution). Label the zwitterion.
12. (3 points) Draw the structure for Ala-Val and label the N-term. And C-term.
13. (4 points) Consider the triple helix.
a) What level of protein structure is represented by the triple helix?
b) What is the main form of cross-linking in the triple helix?
c) What protein is made up of triple helices?
d) What are the two modified amino acids in triple helices?
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14. (3 points) What are hydrophobic interactions in a protein? Show an example.
15. (2 points) How does heat denature proteins?
16. (2 points) Give the substrate and the type of reaction catalyzed for each of the
following enzymes:
a) alcohol dehydrogenase
b) amylase
17. (3 points) If an enzyme has a maximum activity at 40C, would the activity be most
reduced at 30C or at 50C? Explain.
18. (2 points) How does irreversible inhibition work?
19. (2 points) What are zymogens?
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20. (3 points) What is an allosteric enzyme and how are they involved in feedback
control?
21. (3 points) Which vitamin is used to make each of the following coenzymes?
a) FAD
b) NAD+
c) CoA
22. (2 points) Consider vitamin K.
a) Is vitamin K water-soluble or fat-soluble?
b) What is the main function of vitamin K?
23. (3 points) Give the names of each of the nitrogenous bases in RNA and label which
ones are purines and which ones are pyrimidines.
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24. (6 points) Consider the following DNA sequence in the middle of a gene, where the
first nucleotide is the beginning of a codon:
TCACCCGGT
a) Label the 5’ and 3’ ends.
b) Write the complementary DNA sequence.
c) Write the mRNA sequence that would be transcribed from the DNA sequence.
d) Write the amino acid sequence that would be translated from the mRNA sequence.
e) Suppose a cosmic ray strikes the DNA and removes the A. Write the new amino
acid sequence that would result.
f) What is the type of mutation in part e (above) called?
25. (2 points) In which parts of the cell do transcription and translation take place?
26. (2 points) What is a plasmid?
27. (2 points) What is a retrovirus and what enzyme does it use to make viral DNA?
28. (3 points) At what location does each of the following processes occur?
a) glycolysis
b) citric acid cycle
c) fermentation
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29. (3 points) The coenzyme FAD is involved in many cellular reactions.
a) What are the three main structural components of FAD?
b) Which of the three components is reduced during conversion to FADH2?
c) In what type of reactions does FAD generally take part?
30. (2 points) Write the overall net reaction of glycolysis.
31. (3 points) Why is it important for pyruvate to be converted to lactate in muscle cells
when oxygen supplies are low?
32. (2 points) Write the overall reaction for the citric acid cycle.
33. (2 points) What are the two mobile carriers in the electron transport chain?
34. (2 points) What is the role of ATP synthase in oxidative phosphorylation?