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CH234, Exam 4, Spring 2006
______
NameLab day (Monday or Tuesday)
This exam consists of a lot of questions. Read over each question carefully. If you do not know something, skip it, and come back to it later. If you have any questions, raise your hand, and I will come to you. I should have the final course grades posted sometime on Thursday.
KEEP YOUR EYES ON YOUR OWN PAPER!
Grading Summary
Page 2. ______(18)
Page 3. ______(8)
Page 4. ______(12)
Page 5. ______(10)
Page 6. ______(10)
Page 7. ______(9)
Bonus ______(4 maximum)
Total ______(67)
Fill in the missing structures and cofactors in the Citric Acid Cycle below.
Consider the two reactions below. Which one is endergonic?
A. / AcetylCoA + Oxaloacetate → citrate + CoASH / -8.0
B. / Acetate + CoASH → AcetylCoA + H2O / +7.5
Suppose the above two reactions were coupled. What does coupled mean?
What is the net result of these two reactions being coupled?
Would the overall coupled reaction be endergonic or exergonic? Explain.
Your book used the following diagram to discuss energy. Explain the main points the textbook author was making with this diagram.
How are the reduced coenzymes produced in the Citric Acid Cycle involved in the production of ATP in the Electron Transport Chain? Why are different amounts of ATP produced from different reduced coenzymes?
You saw in Section 16.6 that aldehydes react with reducing agents to yield primary alcohols. The Fischer projections of two D-aldotetroses are shown below. One of the two can be reduced to a chiral product, but the other yields an achiral product. Explain.
Convert the Fischer projection of the sugar below into the cyclic hemiacetal form. Draw the Haworth projection of the alpha form of the sugar. What does alpha mean in this context?
Is this sugar a D- or an L-sugar? Explain your answer.
Amylose (a form of starch) and cellulose are both polymers of glucose. What is the main structural difference between them? Draw this difference out so I can clearly see it. What are amylose and cellulose used for?
Gentiobiose has the following structure.
Does gentiobiose have an acetal functional group? If so, circle it and label it.
Does gentiobiose have a hemiacetal functional group? If so, circle it and label it.
What simple sugars would you obtain from hydrolysis of gentiobiose?
Draw D-Fructose in a Fischer projection.
Are D-Fructose and L-Fructose identical? If not, what type of isomers are D-Fructose and L-Fructose?
What generalizations can you make about D-Fructose and L-Fructose with respect to the following properties?
Melting point?
Rotation of plane-polarized light?
Solubility in water?
Relative sweetness?
Bonus!
What is the following molecule? Why is it important in metabolism? What kind of reactions does it do?