Chem 481 F10 HW 11-19-10-1

Chem 481 F10 HW 11-19-10-1 - Name Dr Steven Wood A few...

Info icon This preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Name ______________________ Final Assignment Chem 481 F10  Dr. Steven Wood A few years ago, on the East Coast, a truckers strike caused a shortage of Twinkies. It seems that annually, 500 million of these cream filled sponge cake snacks are consumed in the U. S. The following questions are based on a snack of a Twinkie, a diet soda and a piece of beef jerky. 1. Assume that the above diet was consumed to break a prolonged fast and that the cream filling in the Twinkie was comprised of all stearic acid (C 18) triacylglycerides. Give a structural representation of stearic acid and outline how a stearic acid travels from the digestive tract to an adipocyte for storage, and then is eventually released and travels to a mitochondrion in the liver in preparation for β -oxidation (DO NOT include the steps of β -oxidation in this problem). Be sure to mention how membranes are crossed and name any necessary carriers (cytosolic or transmembrane) or cofactors. You may just use compound names if you like. 2. Show the steps necessary to convert this stearate into one molecule of “fuel” for the citric acid cycle. Include structures, indicate any necessary cofactors and indicate what type of reaction each step is i.e. dehydrogenase, oxidase, oxidation-reduction etc. and the name of the enzyme that catalyzes the final liberation of this “fuel”. 1
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
3. If the triacylglycerides of the cream filling contained oleic acid (steric acid with a double bond at the 9 position) as well, outline any modifications to the above set of reactions necessary to convert all of the carbon atoms in this compound to citric acid cycle “fuel”. You need only show those reactions that differ from the stearate example. 4. During this fast, oxaloacetate levels in the liver have dropped. Briefly explain why they dropped. Under these conditions fatty acids would become the chief fuel source. What would happen as the acetyl- CoA levels increase as a result of the decreased levels of oxaloacetate. What are the structures of the three compounds exported from the liver to be utilized for fuel by the other tissues under these circumstances? 5. The diet soda is sweetened with aspartame (nutrasweet®) which is the methyl ester of the dipeptide, Asp-Phe. Draw out the structure of aspartame and explain why, in most individuals this sweetener would be a source of Tyr and why the diet drink carries a warning for individuals with phenylketonuria.
Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern