C485 Final Exam Fall ‘12
Name___________________
Legible please!
Do not use acronyms. 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. GOOD LUCK
1. (10pts) Assume four electrons pass completely through the light reactions of
photosynthesis. What is the stoichiometry of the compounds produced or used.
______ O2 ______NADPH _______ATP ______H+ pumped out ______H+ taken up
What if cyclic photophosphoryation is operative?
______ O2 ______NADPH _______ATP ______H+ released ______H+ taken up
2. (10pts) Diagram the Q cycle of photosynthesis, showing where and how many
quinone/quinol molecules are used and where and how protons are taken up and given
off. Make sure you account for the stoichiometry of the cycle and show where electrons
wind up. Make sure to show where the lumen and stroma are.
3. (10pts) In one sentence or less, describe the role of each photosystem component
named below:
Cytochrome bf
Manganese Center
Carotenoids
P680
Plastocyanine
4. (10 pts) List the environmental conditions/small molecules that activate rubisco and/or
enzymes of the Calvin cycle.
a_____________________
b_____________________
c_____________________
d_____________________
e_____________________
5. (8pts) Draw a balanced equation for the overall reaction mediated by the Calvin cycle,
assuming the production of one glucose molecule from carbon dioxide. How many
turnovers are required from Rubisco for each glucose produced?
6. (10pts) Starting from GAP and F-6-P, show all the reactions of the Calvin cycle used
to regenerate RuBP. You MUST use structures. No enzyme names required. Please
note which of these reaction(s) does NOT occur in the pentose phosphate pathway. Show
how glucose is generated as a “by product”.
7. (8 pts) Outline the oxidative portion of the pentose phosphate pathway. What
provides the driving force for these reactions?
8. (8 pts) The pentose phosphate pathway operates in four modes. What are they, and
how is the pathway altered to accommodate the needs of the cell.
Mode 1
Mode 2
Mode 3
Mode 4
9. (8 pts ) The regulation of glycogen phosphorylase differs between the muscle and
liver. Diagram this regulation and show how it differs. What is the physiological
rationale for this?
10. (10 pts) Diagram the structure of glycogen, showing all glycosidic linkages and
outline the biosynthesis, including the biosynthesis of any required activated
intermediates.
11. (8 pts) What are the basic steps of signal transduction?
12. (10 pts) Outline the signaling pathway for glucagon, showing how it exerts its effect
on both glycogen breakdown and synthesis.
13. (12 pts) Consider the processing of the 11-carbon fatty acid shown below via betaoxidation.
Outline (structures please) how this molecule would be processed via beta oxidation.
(You do not need to enumerate repeated steps.) Make sure you show any products that
cannot be processed via beta-oxidation. Outline the intermediates involved in converting
this remnant into a commonly used metabolite. To the extent possible, calculate the yield
of ATP from the metabolism of this 11-carbon fatty acid. Do not consider the energy
from the remnant. Please show how you do this calculation.
14. (6 pts) Outline the process by which substrates of beta oxidation are transported into
the mitochondria. Structures please.
15. (8 pts) Outline the process by which the cytoplasm obtains Acetyl CoA for fatty acid
synthesis. (structures please). What other benefit does this provide for the cell?
16. (8 pts) List the differences between fatty acid biosynthesis and breakdown.
17. (12 pts) Give the major carbonaceous breakdown product(s) of the following amino
acids (structure please): (Must not be an amino acid)
Threonine
Proline
Leucine
Isoleucine
Arginine
Histidine
18. (8 pts) For the following reactions, list whether they are oxidations, reductions, or
neither. For oxidations and reductions, put down the number of electrons involved.
19.( 20 pts) Draw the structure required- label it and below it show where the carbons are
derived from at the beginning of the pathway moving forward. You must use structures
and labels. Ambiguities will not be counted.
Example:
Alanine
IMP (base only)
CTP (base only)
Histidine
Lysine
20. (8 pts) Describe the role of the following structures:
High-density lipoproteins-
Chylomicrons-
Leptins-
Low-density lipoproteins-
21. (10 pts) Draw the mechanism for the final step in tryptophan biosynthesis
22. (10 pts) Draw the mechanism for the conversion of S-adenosyl homocysteine to
homocysteine and adenosine.
23. (10 pts) Threonie may be degraded to glycine and acetaldehyde. Draw the
mechanism of this transformation. (Show the full transformation from start to finish.)
24. (10 pts) Outline. (structures) the biosynthesis of leucine.
25. Draw a transketolase reaction from the pentose phosphate pathway. Show the
mechanism (structures and arrows, please).
Point breakdown
Possible
actual
1)
10
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2)
10
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3)
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4)
10
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5)
8
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6)
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7)
8
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8)
8
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9)
8
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10)
10
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11)
8
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12)
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13)
12
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14)
6
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15)
8
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16)
8
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17)
12
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18)
8
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19)
20
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20)
8
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21)
10
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22) 10
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23) 10
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24) 10
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25) 10
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Total Out of 242
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