LSM1301 Semester 2 2007‐08
Page 1 of 2
Assignment 2
Questions
The questions are based on a metabolic pathway which starts with the following reaction. CO2 + H2֖ HCOOH
1. The first reaction shown above is catalysed by Enzyme A.
(a) What type of reaction is catalysed by Enzyme A and which class should the enzyme be classified under?
[2 marks] (b) Enzyme A requires the assistance of a cofactor to catalyse the reaction. The
cofactor is an organic molecule with three phosphate groups and acts as a co- substrate. What is the most likely cofactor of Enzyme A? Explain how you had arrived at your answer.
[2 marks]
2. The carbon in HCOOH will then be transferred to another cofactor. After a series of reactions catalysed by various enzymes, the cofactor will transfer the carbon to a metalloprotein. Based on the description, what is the most likely cofactor? Explain how had arrived at your answer.
[1 mark]
3. Enzyme B would then catalyse the synthesis of acetyl-CoA from CoA, CO, and the carbon that is now carried by the metalloprotein. Enzyme B can also catalyse the formation of CO from CO2 in another section of the protein.
(a) There is a narrow channel connecting the CO producing section to the acetyl- CoA producing site. Why is it necessary to have the channel?
[2 marks] (b) What can you conclude about the structure of Enzyme B?
[2 marks]
4. An organism capable of carrying out this metabolic pathway can live on CO2 and H2
alone. How should such an organism be classified as, in terms of how it obtains its energy?
[1 mark]
Task
1. Please download the “Assignment 2 Answer Sheet.doc” file from the “Answer Sheets” folder of the “Notes, Practical Protocols, and Assignments - Semester 2 2007-08” Workbin, and answer the questions above by filling in the corresponding cells of the table.
LSM1301 Semester 2 2007‐08
Page 2 of 2
2. Name your file in the following format, “yourmatricnumberAssignment02”. If your matriculation number is U071234A, the filename should be
“U071234AAssignment02”. Marks may be deducted if your file is not renamed according to the stated format.
3. If you are using Microsoft Office 2007 or any other word processing applications, please save your file as a “Word 97-2003 Document”. It is your responsibility to correctly save the file so as to ensure that the person making your assignment would have no problems opening and reading your file.
4. Please upload your document to the “Assignment 2” folder of the “Submission of Assignments” Workbin by 1200 hours, 29 March 2008 (Saturday). There will be a 50% penalty for documents uploaded to the “Assignment 2 (Late)” folder. 5. Please ensure that your file has been successfully uploaded to the Workbin folder.
The file you have uploaded should appear listed in the Workbin folder.
6. To ensure that the correct file was successfully uploaded to the Workbin folder, please login to the IVLE website after a few minutes you have logged-out,
download the file you had uploaded to the folder, and open the downloaded file to verify that it is the correct file.
7. It is your responsibility to ensure that the correct file was uploaded successfully to the Workbin folder. You will not be given a second chance to upload another file to the Workbin folder after the deadline has passed.
8. If you decide to upload an updated version of your submission before the deadline, please delete the older file before uploading the newer file.
Notes
1. The final weightage of this assignment is 10%.
2. The deadline is 1200 hours, 29 March 2008 (Saturday).
3. The late submissions deadline is 1200 hours, 31 March 2008 (Monday). 4. There will be a 50% penalty for documents uploaded to the “Assignment 2 (Late)”
folder.
5. There will be no marks for those who missed the late submissions deadline. 6. Please note that your file will be submitted to the Turnitin website and your name
will be reported to the Dean’s Office if any of your answers is found to be similar to other students’ responses or to other sources.
