BIOLOGICAL MOLECULES WORKESSION 5
SUMMATIVE ASSESSMENT LAB REPORT
1. General comments: Keep the report concise and focused- rambling, excessively long reports do not necessarily collect more marks. Word-processed reports are easier to read, but hand-written is acceptable if clear and legible. If you are using a word processing package, use a minimum of 10-point size font, with 1.5 line spacing- this makes it easier to read and for your demonstrator to write in feedback comments. Note that graphs must be drawn by hand- computer-generated graphs are not acceptable. It sounds obvious, but please make sure that your name and that of your demonstrator is written at the top of page 1 of your report. Please staple all the sheets of your report together.
Other general guidelines on writing lab reports are given in the BMS-1 study guide (and reproduced on page 2 of this document).
2. The report: Give your report a logical format-
· a BRIEF ‘Introduction’ section outlining the aims of the experiment. Give some background information- what is the role of alkaline phosphatase? Is it used as a diagnostic indicator? A third to half a page is adequate here.
· Materials and Methods section- this is an outline of the methodology. An extensive, detailed reproduction of the methods in the workbook is not needed, but you should specifically mention any changes or modifications introduced by you. Explain why you introduced these changes.
· Results section- clearly state the outcome of the experiments. When giving numerical values that you have determined experimentally, make sure you give the correct units. Data should be presented on suitable graphs. Why not give each graph a figure number? It’s then easier to direct the reader of the report to the appropriate data presentation by referring to the appropriate figure number in the text. This is how it is done in scientific papers.
· Conclusion. Do not simply reiterate the results- explain what they mean. We are also looking for the ability to critically evaluate the experiment. How could you have improved the quality of the data? Where might errors have crept in? What are the key criteria that make an enzyme assay suitable as a tool to aid clinical diagnosis? Does this assay fit those criteria?
3. Clinical case questions: Keep your answers focused. There should be no need to exceed one A4 page in total for the answers of all three questions. You are expected to come up with a specific diagnosis for each case. Explain how you arrived at your diagnosis. Where relevant, outline how you were able to eliminate other potential diagnoses from each case.
APPENDIX: WRITTEN LABORATORY REPORTS
Please make sure that you read this part and the following sections very carefully so that misunderstandings do not arise later on.
During Biomedical Sciences-1 you will be required to submit written reports for some of your laboratory experiments. These must be prepared and handed in to your demonstrator for assessment by the date specified. Your marked report will contain written feedback in the form of specific comments and guidance. You should ensure that you understand all the points raised.
Assessment may be summative, where the mark will form part of your overall assessment for the course (see the previous section on ‘Assessment’), or it may be formative, where the mark will not contribute to your final assessment but the aim is primarily to help you understand how to improve your report writing skills. In 2008, Biological Molecules Work Session 5 “Alkaline Phosphatase: So what can enzymes tell us?” is a summative assessment contributing 33% of your marks for this ICU. The write-up for this practical will take the form of a short lab report and written answers to some theory questions relating to clinical cases. As practice for writing up this summative assessment, you will also prepare a short lab report for part of Biological Molecules Work Session 2 “Protein Purification”. Your demonstrator will give you feedback on this formative assessment before the deadline for handing in the summative assessment lab report (see ‘Assessment’ section earlier in this Study Guide for hand-in dates). To help you, advice and guidelines on lab report writing are provided below.
2. Advice on preparing written reports
The essence of a written report is to communicate your findings and conclusions to someone else. Therefore, it must be readily intelligible to another reader and not just to you. It must be obvious what primary observations you made, how you processed the data, and what your conclusions are.
For these reasons you will have to give considerable thought to how you organise your reports. While it is impossible to give definitive rules, each case having to be taken on its own, the following is given to assist you:
§ Your Report should be organised in sections: Introduction (a brief resumé of why the experiment was done); Methods (in general merely refer to the sections of this workbook; do not rewrite the instructions); Results and Conclusions.
§ You will save time if you have read and understood the practical notes before you do the experiment and you have recorded your data in a suitable form during the experiment.
§ Do not waste time rewriting the data you recorded in the laboratory to achieve a pristine copy.
§ Show any calculations in full so they can be checked but for repetitive calculations show only a specimen in full.
§ Remember that a numerical result usually cannot be given without units.
Tables, bar charts and graphs are good ways of displaying your results and conclusions. However, they should be as simple as possible, consistent with accuracy and conveying the necessary information. Each must have a concise informative title. The test of a good display item is that it conveys a clear message without the need for extensive reference to the text.
3. Drawing graphs
Graphs are a great visual aid and are frequently used to represent the results of experiments. Relationships between measured quantities, errors in measurements and the presence of anomalous measurements are often readily apparent. Graphs allow straightforward averaging of experimental measurements, interpolation between measurements and determination of the equation relating measured quantities.
§ Give your graph a title
§ Label both axes to show clearly what variable you are plotting, and its units.
§ Choose the axis scale to make plotting simple, e.g. let 10 small divisions equal 1, 2, 5, 10, etc. It takes longer, and you are more likely to make a mistake, if you choose a difficult scale.
§ Choose the ranges of the axes so that the points are suitably spread out on the graph paper and not all cramped into one corner - this may mean excluding zero from the axis.
§ Plot the independent variable along the horizontal axis and the dependent variable along the vertical axis.
§ Plot the experimental points clearly. Tiny dots may be confused with dirt on the graph paper and big dots give loss of precision. Either or ¤ are preferable. When you are plotting more than one set of data on a graph use different symbols.
§ When taking readings, generally spread them out evenly over the range of values of the quantity measured. The exceptions to this are when you want to measure an intercept (e.g. 1/V vs 1/S in a Lineweaver-Burk plot, see Biological Molecules Works Sessions 4 and 5), when it is desirable to have a few extra points close to the axis, or if there is a change in the shape of the graph (e.g. a peak) when extra points in this area will give greater precision.
§ Draw a straight line or a smooth curve through points plotted on the graph, rather than joining up successive points by short straight lines. If the points show wide 'scatter' due to experimental error, the best smooth curve or straight line should be drawn through the points, as illustrated by the examples below. Note that the eventual line may not actually pass through any of the experimental points. Deciding on the best line requires practice, but as a rule the points should be evenly distributed on either side of the line.
Note: All graphs must be hand drawn. Computer produced graphs are not acceptable.