9900 Final

Part I: Dr. Lam’s portion (30 marks total) Answer all questions (1) Sucrose translocation is a vital physiological process in higher plants. It is believed that sucrose transporters will play a major role. However, purification of such sucrose transporters using biochemical means was not successful. (a) Suppose you are the first scientist in the world attempting to clone the genes encoding sucrose transporters. A yeast strain that is not able to uptake or breakdown extracellular sucrose was made available to you. Describe how you can make use of this yeast strain to clone sucrose transporters from higher plants. (6 marks) (b) Suppose you have successfully cloned one sucrose transporter gene. Design an experiment to test if this particular sucrose transporter will play a major role in overall sucrose translocation. (4 marks) (2) Mouse embryonic stem cells (from a brown-fur mouse) containing a foreign gene A were transferred to a developing blastocyst (from a white-fur mouse). The blastocyst was then allowed to develop inside the body of a pseudo-pregnant female mouse. The resulting progenies were found to be chimeric (i.e. some cells contain gene A and some cells do not). (a) Explain what are embryonic stem cells. (1 mark) (b) To use embryonic stem cells in transgenic mice experiments, explain why it is important to prevent these cells from differentiation. Suggest some measures to help preventing the differentiation to occur. (3 marks) (c) Explain why chimeric progeny mice instead of pure lines were obtained in this experiment. (2 marks) (d) Describe how you can obtain pure lines from the chimeric mice. (2 marks) (e) After you get the pure lines, describe how you can test the stable integration of gene A in these lines. (2 marks)

(3) Protein P is believed to play an important role in light signal transduction in higher plants. To show that protein P is located in the nucleus in the absence of light, a P-GUS fusion construct was transformed into the model plant Arabidopsis thaliana. GUS is commonly used as a reporter system since its activity is relatively easy to assay. (a) Do you think the P-GUS fusion used in this experiment is an operon fusion or a protein fusion? Explain your answer. (3 marks) (b) When transforming the P-GUS fusion construct into Arabidopsis thaliana via Agrobacterium-mediate techniques, a binary vector system was used. Explain what is a binary vector system. (2 marks) (c) It was found that higher transformation efficiency was exhibited when using Agrobacterium strain X as compared to strain Y. Suggest two possible reasons. (2 marks) (d) The data of a separate experiment showed that several light induced genes express in both light and dark conditions in a plant mutant that cannot produce protein P. Combining this new observation with the P-GUS results stated above, suggest a possible function of protein P. (3 marks) Part II: Prof. Sun’s portion (22 marks total) Fill in the blank (0.5 mark each) 1. In the Human Genome Project, a) “quality” sequence, the 4As, means Accurate, Assembled, Affordable, and . b) 5% of the research project is set aside to study and address the ethical, and social implications (ELSI). 2. Modern medicines include recombinant therapeutic proteins, protein agonists and antagonists, and gene therapy. 3. In gene therapy, there are two strategies to deliver the therapeutic gene into target organ. They are in vivo strategy and strategy. 4. Subunit vaccine uses the

of a pathogen organism rather than the

whole organism in vaccine production. 5. Tissue plasminogen activator (tPA) was the first recombinant therapeutic protein to be produced by cell culture. 6. Insect cell culture has the advantages of high level expression, and post-translational modification. 7. Molecular approach for crop improvement include gene addition, gene subtraction and . 8.

is the process of using biological agents to remove toxic waste from the environment.

10. In the United States, production of genetically modified crops/foods follows the regulations and requires the approval of the United States Department of Agriculture (USDA), (EPA) and Food and Drug Administration (FDA). A. Answer all the following questions 1. What are the major goals of Human Genome Projects? (2 marks) 2. How will scientists benefit from the sequence provided by the Human Genome Project? (2 marks) 3. With the rapid progress of molecular biotechnology, in your opinion, where the future health care needs and opportunities are? (2 marks) 4. You are recruited by a biotechnology company to participate in the production of a vaccine againts a newly discovered virus that infect humans. The rod shape virus is a RNA virus and has a coat consisting of two different proteins. You are asked to develop a research and development plan for the vaccine production. Outline your plan. (3 marks) 5. As the citizens of Hong Kong are voicing their desire of labeling the genetically modified (GM) foods, a freshly graduated biology student with biotechnology background, you see the need in GM food detection and thus try to set up a small biotechnology company for this business opportunity. List the essential instruments that you may need and the kinds of detection service that you may offer. (3 marks) 6. The yields of hybrid rice are about 30% higher than the regular rice. However, the quality of the hybrid rice is not as desirable. This lower quality is largely due to the undesirable property of rice starch, which is determined by the proportion of the straight chain and branch chain starch components. Suggest how you may genetically modify the rice starch composition/property for improvement? (3 marked) 7. Opponents and people who have safety concerns about GM foods often raise the question that, despite there is currently no evidence showing GM foods are unsafe to consume, they may cause ill effect(s) 50 year later. What is your opinion of this question? (2 marks) - END -