Group Members: _____ _______________ ___________________________________________Date: ___________ LI ______________________ Unique __________ Day: __________ Room: _______ Lab Start Time ________ BIO206L Fall 2012 As stated in the syllabus, first answer all questions individually. Then, meet as a group to compile and submit a cohesive answer and one printed report submitted at the beginning of the next laboratory period. Include YOUR “Data & Results”, sketches, acquired digital images, etc. as directed by your laboratory instructor. Show your work for all calculations and/or print your MS Excel data sheets. When reporting YOUR values, be sure to include proper units where necessary. Adhere to UT’s Honor Code and course policies. If you use a secondary resource, cite it! Please find a balance between brevity and completeness. Exercise 4 Analysis To be completed as a group and turned in at the beginning of your next laboratory period. Include your “Data & Results”, sketches, acquired digital images, etc. as directed by your laboratory instructor. Show your work for all calculations and/or print your MS Excel data sheets. Be sure to include proper units where necessary. Adhere to University’s Honor Code and course policies. Balance between brevity and completeness. 1. Compare the two methods of counting the Vibrio natriegens cultures. For both the hemacytometer and the spectrophotometer list any advantages and disadvantages for each method. 1 point 2. Present a series of detailed drawings with observational notes and labeled features of the various bacterial slides (the prepared mount of “mixed” bacteria containing species: Bacillus megaterium (rod shaped), Micrococcus luteus (spherical-filamentous shaped), Rhodospirilium rubrum (sprial shaped)) as well as the ones you prepared using V. natriegens and E. coli . Dimensions (µm) and total magnification should be indicated. When using the hemacytometer or other microscopic observations, the cells may be stained or unstained. What would be some of the advantages or disadvantages of using each? 2 points unstained stained Fall 2012 Ex 4 Analysis Page 1 of 5
Group Members: _____ _______________ _____________________________Exercise_______Date: ___________ LI ______________________ Unique __________ Day: __________ Room: _______ Lab Start Time ________ 3. Present your data of the growth of V. natriegens as recorded indirectly by measuring optical density (O.D.) at 12-min time intervals in three different ways. A.) plot the data as x-y scatter plot of time (min) on the x-axis and O.D. measurements on the y-axis. B.) re-plot this data on a semi-logarithmic y-axis. c.) Calculate the natural logarithm of O.D. measurements and re-plot with Ln (O.D.) on the y-axis. Provide a brief description of each graph. 2 points 4. Using your graph with Ln (O.D.) on the y-axis versus time (min) on the x-axis, insert a linear trendline of the linear portion of the graph – the exponential growth phase. (Note you will have to select a subset of your data.)
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