C485 Exam I Fall ‘15
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. (12 pts) (a)There are three organic molecules (proteins or small molecules) that
directly (or indirectly) regulate the Calvin cycle. What are they? How do they do this,
and explain the logic of their function given the makeup of the cycle. (b) What inorganic
factors regulate the function of the cycle? How do they do this, and explain the logic of
their function given the makeup of the cycle.
.
Mechanisms 2-5!!!!!
2. (8 pts) Draw an example of an transaldolase reaction from the pentose phosphate
pathway. Draw its mechanism. (YOU MUST USE STRUCTURES AND ARROWS).
You may assume active site general acids and bases as necessary.
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3. (10 pts) A basic carbon-carbon bond forming reaction in the Calvin cycle transfers two
carbon fragments. Give an example of this reaction and draw its mechanism. You may
assume active site general acids and bases as necessary. Please show the necessary parts
of any cofactors. (YOU MUST USE STRUCTURES AND ARROWS). Please use the
back of the exam if necessary.
4. (10 pts) Give an example of a carbon-carbon bond forming reaction in the Calvin
cycle that transfers a one carbon unit. Draw the mechanism of this reaction, showing the
active site structure and any special enzyme features that are at play here. Please use the
back of the exam if necessary.
2
5. (10 pts) An unwanted side reaction occurs during the dark reactions of photosynthesis.
What is this reaction? Draw its mechanism. Under conditions of drought this reaction
becomes much more prevalent. Why is this? Use the back of the exam if necessary.
6. (8 pts) What is structure of glutathione? Explain its role in red blood cells. How does
an important enzymopathy affects this function?
7. (8 pts) Diagram the Q cycle and explain how this accounts for the stoichiometry of
proton pumping and uptake in the relevant complex.
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8. (8 pts)Assign each function or product in the right column to the appropriate structure
or pathway in the left colum. (there may be more than one function assigned and they
may be used more than once). or pathway in the left colum. (there may be more than one
function assigned and they may be used more than once).
(a) chlorophyll _________
(b) light-harvesting complex _________
(c) photosystem1_________
(d) photosystem II_________
(1) O2 generation
(2) ATP synthesis
(3) light collection
(4) NADPH synthesis
(5) separation of charge
(6)light absorption
(7) transmembrane proton gradient
8. (8 pts) Assume that a cell only needs to synthesize ribose, but not NADPH. Please
diagram how this can be done. (structures please). You may assume that the cell has
adequate access to hexoses.
9. (12 pts) What is the overall stoichiometry of photosynthesis in chloroplasts? If eight
photons are absorbed, the net yield is _______O2, ________NADPH_________ATP
The amount of water oxidized is _______H2O, the number of protons released to the
lumen is ________H+, and the number taken up from the stroma is _________H+
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10. (12 pts) Consider the regeneration portion of the Calvin cycle and the nonoxidative
portion of the pentose phosphate pathway. From a fundamental thermodynamic
perspective, what are the major differences in these two pathways? Explain how these
differences fit into the differing goals of the two pathways.
Redox Time!!
11. (10 pts) For each reaction, say whether it is an oxidation, reduction, or neither. State
the number of electrons associated with the process.
Electrons and process ________________
Electrons and process _________________
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Point breakdown
Possible
actual
1)
12
________
2)
8
________
3)
10
________
4)
10
________
5)
10
________
6)
8
________
7)
8
________
8)
8b)
9)
8
8
12
________
10)
12
________
________
11) 10
________
TOTAL 110
___________
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