PAPER REFERENCE: BIO1140 EXAMINATION NUMBER: DESK NUMBER:

UNIVERSITY OF OTTAWA DEPARTMENT OF BIOLOGY INTRO TO CELL BIOLOGY FINAL EXAM 2010-2011MODULE NO: BIO1140

MODULE TITLE: MOLECULAR BIOLOGY TIME ALLOWED: 3 HOURS (180 MINUTES)

This paper has three parts: Section A: Short answer questions (30 marks) Answer ALL questions in the spaces provided on the examination paper. The marks available for each question are indicated on the paper. Section B: Problem questions (20 marks) Answer ALL questions in the spaces provided on the examination paper. The marks available for each question are indicated on the paper. Section C: Long answer question (30 marks) Answer either question A or question B. Write your answer in the lined space provided on the examination paper. Your essay will be marked out of 100. Total marks available for this paper - 80.

For marker/office use only: 1 2 3 4 5 6 7 8 9 C Total

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SECTION A: Short answer questions Answer all questions in the spaces provided. Mark total for this section - 30 1. a) Briefly outline the series of events involved in T-DNA transfer from Agrobacterium tumefaciens to plant cells. (4 marks)

b) Explain why co-expression of the P19 protein with GFP significantly boosts GFP expression in transformed plant cells. (4 marks)

2. You want to express a therapeutic protein in sheep and decide to use the nuclear transfer technique to achieve this. a) How would you create the cells from which the donor nuclei would be derived? (2 marks)

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b) Briefly describe another technique that could be used to create a transgenic sheep. (4 marks)

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3. You need to do some biochemical experiments on a purified E. coli enzyme called TesT, which is known to contain a disulfide bond to be functional. You will try to overexpress the protein from an E. coli expression vector. What strategies would you use for the purification of the enzyme from E. coli to ensure that it was both pure and in a functional form at the end of the purification? (9 marks)

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4. Explain the mechanism and advantages of using the dihydrofolate reductase methotrexate selection systems in mammalian expression vectors. (4 marks)

5. Give three reasons why genetically modified bacteria that perform well in laboratory tests fail to increase degradation rates of pollutants in contaminated sites. (3 marks) (i)

(ii)

(iii)

The space above this line should be sufficient for your answer

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SECTION B: Problem question Mark total for this section - 20 6. You work for a small biotechnology company that specialises in metabolic engineering. You have been asked to design a bioprocess to improve the yield of compound H from the metabolic pathway shown below. Describe five strategies you would use to improve the flux from pyruvate to compound H. (20 marks) In the figure the text in italics represent the genes that encode the enzymes that convert the metabolites in the pathway (e.g. tesA encodes the protein that converts pyruvate to A). The dotted line represents feedback inhibition. Your answer can be continued onto the following page.

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1.

Outline briefly: a) The molecular basis by which bacteria regulate gene expression in response to changes in population density. (4 marks)

b) Two examples of how such a sensory mechanism is important for the lifestyle of particular bacterial species. (4 marks) (i)

(ii)

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2. Describe step by step the mechanism proposed for plasmid segregation by type III partition cassettes. (8 marks)

3.

Illustrate, using a labeled figure, the key components of the E. coli chemosensory system, indicating their biochemical activities. (8 marks)

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4.

a) What method was used by Woese and Fox in 1977 to determine that methanogens were not bacteria? (1 mark)

b) Why does the information generated by this and related techniques continue to be important? (1 mark)

5.

a)

What is anaerobic digestion? (2 marks)

b)

How do microbes contribute to anaerobic digestion? (4 marks)

The space above this line should be sufficient for your answer

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6.

Describe the mechanisms that control initiation of chromosomal DNA replication in bacteria. (8 marks)

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SECTION C: Long answer question Answer either (a) or (b) in the space provided. Please circle a) or b) to indicate the question answered. EITHER a) The commercial planting of transgenic crops has not been widely adopted in Europe. Discuss whether there is scientific evidence for any of the concerns about this technology

OR b) Why are therapeutic proteins like human DNaseI and Factor VIII currently expressed in mammalian cell culture? What is the potential to engineer a better expression system.

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