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Name ______________________________
Chem 451
Winter 2005
MIDTERM II
1. Answer the following questions on the glyoxylate cycle.
(3 pts)
a. Name the two unique enzymes of the glyxoylate cycle.
b. State the purpose of the glyoxylate cycle.
2. Answer the following questions on the urea cycle:
(6 pts)
a. What two waste products does the urea cycle get rid of?
b. In what organ does the cycle take place.
c. Write the reaction of glutamate dehydrogenase. What is the role of this reaction in the
urea cycle
3. For the following, describe their function:
Low density lipoprotein(LDL)
THF
(2 pts each)
4. Name two compounds derived from cholesterol.
(2 pts)
a. ____________________________________
b. ____________________________________
5. Illustrate the transamination reaction with structures between an α-keto acid and
glutamate.
(6 pts)
6. What is the function of the following enzymes/molecules:
a. ubiquitin
b. carbamyl phosphate synthetase (CPS I)
c. propionyl carboxylase
d. 2,4 dienoyl reductase
(4 pts)
Name ______________________________
7. Describe how epinephrine regulates the β-oxidation pathway and cholesterol
biosynthesis.
(4 pts)
8. For the following precursors, name an amino acid each one can form. (6 pts)
a. oxaloacetic acid
b. pyruvate
c. α-ketoglutarate
d. 3-phosphoglycerate
e. ribose 5-P
f. PEP + erythrose 4-P
9. HMG CoA lyase and HMG CoA reductase both use HMG as a substrate.
(4 pts)
Name the cellular location of each enzyme.
Identify the metabolic pathway they are used in
10. Diagram the carnitine shuttle and describe its function.
(4 pts)
11. Complete the following table comparing Fatty Acid Oxidation (FAO) and Fatty Acid
Biosynthesis (FAB) :
(10 pts)
FAB
FAO
Cellular compartment
Electron carriers
Orientation of hydroxyacyl
Group
2 carbon unit donor
direction of synthesis/
oxidation
12. A number of genetic deficiencies have been described for Acyl CoA dehydrogenase.
This deficiency presents itself early in life after a period of fasting. Symptoms include
vomiting, lethargy, and sometimes coma. Blood levels of glucose are low but starvation
ketosis is absent. Answer the following questions:
(6 pts)
a. Write out the reaction catalyzed by acyl CoA dehydrogenase.
b. Suggest a biochemical explanation for the last two observations.
13. Describe the use statins in cholesterol management.
(3 pts)