C483 Exam 3 2014
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Name
Instructions: Please read all questions carefully. Use structures if they are called for. Unless noted otherwise, please draw them in the correct protonation state for pH 7.4. Do not use acronyms unless specifically directed. If you need more space, use the back of your paper. No calculators or electronic devices. Answers should be short and to the point. If you have extra material that is incorrect, points will be deducted. This is a one hour exam, but you have two hours to complete it. Good luck.
1) 10pts What are the main purposes of the citrate/pyruvate shuttle? Please draw the reactions of this shuttle.
2) 20pts totalStarting with butanoic acid (C-4) diagram the reactions of its breakdown via beta-oxidation (structures please). How many ATP’s may be generated by complete conversion of this molecule to carbon dioxide (details please)? Consider pentanoic acid. After one cycle of oxidation, there is a remnant that is converted into a Krebs cycle intermediate. Please diagram this conversion (structures please) and draw the mechanism of both reactions involved.
3) 6pts Whatare the major differences between fatty acid oxidation and synthesis?
4) 8pts Draw the mechanism for the transaldolase reaction in the pentose phosphate pathway.
5) 8pts Draw the mechanism for a transketolase reaction in the pentose phosphate pathway.
6) 8pts What is meant by reciprocal regulation? Give an example of this from glycolysis and gluconeogenesis and from glycogen breakdown and synthesis.
7) 4ptsGluconeogenesis requires four enzymes that are not enzymes of the glycolytic pathway. These four enzymes are: (If you don’t know the enzymes, just draw the complete reactions using structures.)
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8) (2 pts each, 12pts total) Answer the following short answer questions (acronyms okay)
a) The protein attached to the glycogen primer required for glycogen synthesis is called: ______
b) In mammals, the hormone ______activates glycogen degradation in the muscles while ______activates glycogen synthesis.
c) The oxidation of succinate uses the enzyme-bound conenzyme ______due to the need for a stronger oxidizing agent than NAD+
d) Ceretain citric acid cycle intermediates serve as bioxynthetic precursors of other materials. Two such intermediates are ______and ______
e) The two mobile electron carriers in oxidative phosphorylation are ______and ______
f) In the biosphere, the two major sources of nitrogen ultimately used for amino acid synthesis are: ______and ______
9. (2 pts each, 10 pts total)True or false
a) ______Each of the 20 common amino acids can be described as being either glucogenic or ketogenic.
b) ______Saturated fats yield more calories per gram than glucose.
c) ______Synthesis of fatty acids occurs by addition of 3 carbons per cycle to the growing fatty acyl group since all three carbons of malonyl CoA are added.
d) ______The carbon atoms of the ring structure of cholesterol are all derived from acetyl CoA.
e) ______Protons are pumped across the inner mitochondrial membrane by complexes I, II and IV during electron transport.
10. (2pts each, 10 pts total) Fill in the blank (acronyms okay)
a) A transaminase enzyme would convert alanine to ______while converting ______to glutamate
b) One of the nitrogen atoms and the carbon atom of urea enter the urea cycle as a single molecule, namely______(or draw structure)
c) The molecules known as ketone bodies are______, ______, ______(or draw structures)
d) The key regulatory enzyme of fatty acid synthesis is______. Phosphorylation of this enzyme causes ______of the enzyme.
e) Phosphatidic acid is activated for conversion to a phospholipid by reaction with ______
11. 6pts Draw the mechanism of succinyl CoA synthetase (fig 13.12 in your book).
12. 5 pts Outline how the Q cycle works. Show the stoichiometry of proton pumping.
Extra credit 15 pts. Each error costs 3 pts.
State whether these reactions are oxidations, reductions, or neither. State how many electrons are involved.
a) 3pts
b)3pts
c)3pts
d)3 pts
e)
Points
Possibleearned
1)10______
2)20______
3)6______
4)8______
5)8______
6)8______
7)4______
8)12______
9)10______
10)10______
11)6______
12) 5______
EC15______
Total122------
1