C485 Exam I Fall ‘13
Name___________________
Legible please!
Do not use acronyms unless instructed to do so. Use structures whenever they are asked
for, or appropriate. Your explanations should be brief. Overly lengthy answers with
irrelevant or erroneous material will receive deductions. Use the back of the page if you
need room. GOOD LUCK
1. (20 Pts) There are two general types of C-C bond-forming reactions in the pentose
phosphate pathway. Please draw an example (structures please) of each one and show
the mechanism (arrows required) of the transformation. You may assume active site
general acids and bases as necessary. Please show the necessary parts of any cofactors.
2. (12 pts) Including cyclic photophosphorylation, there are three mobile electron
carriers in the light reactions of photosynthesis. Explain what these are (name and brief
description) and say what their role is.
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3. (8 pts) What is the most common enzymopathy occurring in humans? What normal
cell function(s) is limited by this enzymopathy. Why are red blood cells particularly
affected? (Hint, they have no mitochondria)
4. (12 Pts) Schematically show proton release and uptake from the major components of
the photochemical system in plants. Make sure to show where the protons come from
and where they go (it may be helpful to use a diagram of the thylakoid to show this).
Please give accurate proton inventory for each component. Assume a complete
photochemical cycle.
5. (10 Pts) What is the energetic requirement for the synthesis of a six carbon
carbohydrate in photosynthesis? Show how you arrive at this calculation.
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6. (8 pts) Explain what accessory pigments are and what role they play in
photosynthesis.
7. (8 pts) What molecules regulate the Calvin cycle? Explain the logic of this regulation.
8. (14 Pts) Draw the mechanism of the unwanted competing side reaction catalyzed by
rubisco. What is the ultimate fate of the abberant molecules produced in this process?
Why is this process referred to as photorespiration?
9. (8 Pts) The pentose phosphate pathway is adaptable to the requirements of the cell.
Delineate what would happen if the cell required equal amounts of NADPH and ATP.
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10. Extra Credit (20 Pts) The pentose phosphate pathway contains 3 reactions that are
structural analogues of reactions that take place in either glycolysis, gluconeogenesis, or
the Krebs cycle (TCA cycle). Please outline these reactions and explain how they are
structural analogues. The Calvin cycle contains an additional three reactions that are
structural analogues of reactions in glycolysis, gluconeogenesis, or the Krebs cycle,
please outline two of these reaction and explain how they are structural analogues.
(These should NOT be the same reactions as those found in the PPP.) (Structural
analogue= same reaction type with a different or the same substrate.)
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Point breakdown
Possible
actual
1)
20
________
2)
12
________
3)
8
________
4)
12
________
5)
10
________
6)
8
________
7)
8
________
8)
14
________
9)
8
________
10)
20
________
TOTAL 120
___________
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