Bio208SampleMidtermAnswers

Bio208SampleMidtermAnswers - Biology 208 Midterm Exam Fall...

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1 Biology 208 Midterm Exam Fall 2007 Answers 1. Define the following: (2 marks each – do not write more than about 2 sentences.) a. Bioinformatics The use of computer programs to store and analyze nucleic acid and amino acid sequence information. If you say “Biology and CS” 1 mark. If you say “Third approach” 1 mark If you only mention as a database (Genbank) = 1.5; mention of amino acids or nucleic acid sequence involvement =1.5 marks b. Probe A fragment of nucleic acid used to detect a target complementary sequence within a mixture. The probe is modified so its base pairing to the target sequence can be easily detected. c. Tm - The temperature at which 50% of a DNA fragment denatures. - Each DNA molecule is half-denatured - Time for 50% to denature = 0.5 marks; - Half way to melting point = 1.5 marks d. Reverse genetics An approach to study the function of a gene of interest. The expression of the gene is reduced or silenced due to the introduction of transgenes (antisense or siRNA constructs). – Part marks: explain forward genetics in detail= 0.5 marks; fail to mention purpose (i.e. determine gene function/phenotypic changes)= 1.5 marks 2. Explain the following statements: (2 marks each) a. It is essential to wear gloves when handling gels stained with ethidium bromide.(2 marks for the concept) Ethidium bromide intercalates between the base pairs of DNA and can do so in the DNA of the scientist using it interfering with transcription and DNA replication. Thus, this compound is mutagenic and carcinogenic so one has to wear gloves and dispose of EtBr-stained gels carefully. Part marks: fail to mention health issue but explained EtBr interaction with DNA: 1.5; if you say stains your hands and makes them orange this was not a health issue. b. List 4 types of information that biochemical analysis might reveal about a purified enzyme. (2) - Kinetic parameters (Km, Vmax) - MW, - Subunit composition, - Binding partners,
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2 - Post-translational modification, - Localization, - Amino acid sequence, - Substrates 3. Explain how to do the following: (use the marks to estimate the amount of detail needed)
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This note was uploaded on 08/18/2010 for the course BIOL BIOL208 taught by Professor Chuong during the Spring '10 term at Waterloo.

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Bio208SampleMidtermAnswers - Biology 208 Midterm Exam Fall...

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