Scientists share their scientific findings by publishing their work in scientific journals. These research articles are usually peer-reviewed before being accepted for publication. Having you submit your lab report in manuscript format is, therefore, good practice for writing a scientific paper. Try looking at some scientific research articles in journals to get a feel for how you should approach your lab report. It is especially important for you to look at the style of the primary reference papers handed out to you as these papers deal with the same subject matter and techniques we will use in class.
Introduction: This section should be a historical overview of the subject of the report. You should state the hypothesis tested as well as the conclusions reached from your data. Example Hypothesis: Yeast strains with different genotypes will react differently to varied experimental conditions.
Materials and Methods: State, in narrative form, using your own words, exactly what was done in the exercise. If possible, you should cite references but, do not list materials. Write this as if you were giving it to someone else to repeat. You may want to divide this section into subheadings such as culture conditions, DNA preps, etc. Try not to use pronouns and write in the past tense. Put your strain table in Materials and Methods. You do not have to include references as to where the strains came from.
Results: The results section contains 2 parts, the graphic representation of the results and the text describing the results.
I. Figures, drawings, graphs, tables, etc. should be well labelled including legends and titles. The figures may be placed within your text (cut/paste/ tape in) or may be put at the end, after your references. Never split a figure between two pages and put only one large figure per page.
II. The text should describe what the data says, but do not interpret the data.
Be objective. You can follow the same sub-heading style as in the methods, for example: Culture conditions, UV irradiation.
Discussion: Discuss the significance of the results obtained. Interpret the data. How does it relate to the literature? Cite references. Place the results of your experiment in context with other information available. Particularly because this is a techniques-driven course, you should discuss the sources of error, controls, appropriateness of methodology, etc. It is also appropriate to discuss what the next experiment might be.
References: List the literature you cited within the body of your report.
Within the text, references should be noted numerically (from 1 to whatever as they appear from beginning to end) as follows:
BMP-2 is present in pre-cartilagenous mesenchyme (1) and is also found .....
If the same reference is used more than once, the earliest number is used repeatedly so a single reference only has one number associated with it.
In the reference section following the discussion, the references are listed numerically, as they appeared in the text such as:
1. Lyons, K. M., Pelton, R. W., and Hogan, B. L. M. (1989). Patterns of expression of murine Vgr-1 and BMP-2a RNA suggest that transforming growth factor-ß-like genes coordinately regulate aspects of embryonic development. Genes Dev. 3: 1657-1668.
2. Maniatis, T., Fritsch, E. F., and Sambrook, J. (1982). Molecular Cloning. A Laboratory Manual. Cold Spring Harbor Laboratory, Cold Spring Harbor Laboratory, New York.
Grading: The methods section will be worth more than usual because this is a laboratory methods course.
Intro 20%
Methods 20%
Results 30%
Discussion (this includes references) 30%
Be sure to use correct grammar, spelling, reference formating, and citations. All reports must be typed.
Reports are due one week after the experiment is completed. Note that many experiments are 2 or more weeks long, so you should not hand in a report after every week. Late reports loose 5% per day.
Sample Lab Report for Exp. 1
Introduction (usually one page)
The budding yeast Saccharomyces cerevisiae has proven to be a very useful model organism with which to study the fundamentals of eukaryotic cell biology. In particular, the genetic approach of isolating and characterising mutant yeast strains has lead to insights in a range of biological problems ranging from amino acid biosynthesis to the execution of the cell division cycle. At the heart of this analysis is the ability to correlate the phenotype of a particular strain with its genotype. By testing a collection of mutant strains under varied growth conditions, it is possible to elucidate the function of specific genes. In this lab,...
Materials and Methods (as long as necesssary, but hopefully less than 2 pages)
Liquid media temperature shift experiments. Yeast strains (see Table 1) were grown in YPD media at 30°C until early log phase. Duplicate samples from cultures were aliquoted...
Strain viability assays on solid media. Yeast strains were innoculated onto either YPD or synthetic plates and incubated for 2 days at 36°C, 3 days at 25°C or 5 days at 17°C. Synthetic complete plates consisted of synthetic deficient plates supplemented with uracil, histidine, adenine, tryptophan, tyrosine, leucine, and lysine...
Alpha factor arrest assay. Yeast strains YMM10 and YMM28 were grown in liquid YPD media (pH4.5) to early log phase at 30°C. Two ml duplicate samples were collected from each culture and 20 ul of alpha factor (0.5 mg/ml) was added to one set....
UV irradiation sensitivity assay. Yeast strains YMM10, YMM16, YMM54 and YMM59 were grown to early log phase in liquid YPD media. Aliquots from each culture were collected, sonicated, counted and diluted to a density of 2,000 cells/ml in sterile water...
Results (about 2 pages of written text)
Figures of primary data. i.e. frog sheets, cell morphologies, plots, etc. interspersed with text describing how the results were generated, any trends they show etc. Please check the papers handed out to you for the proper form the figures should be in. It may be useful to use the same subheadings as were used in Materials and Methods (at least those that apply).
Phenotypic analysis of mutant yeast strains. One way to elucidate the role that specific genes play in the cell is to examine the phenotypes of known genetic mutants. A panel of mutant and wild type yeast strains were grown to early log phase and then tested for their ability to survive...
UV sensitivity assays. In order to determine whether specific mutations could affect a strains ability to repair DNA damage, four separate yeast strains were assayed for their sensitivity to UV irradiation... As seen in Figure 4, cell deaths occurred......
Discussion (about 2 pages)
The isolation and characterization of cell division cycle mutants has been a very useful approach for deciphering the genetics of cell proliferation. Through phenotypic analysis, it has been possible to determine the roles and functions that these genes play in cell division in vivo.....
Some common errors to avoid
Always write out completely the names of things the first time you use then. Thereafter, you can abbreviate. EX. 1 The budding yeast Saccharomyces cerevisiae.....S. cerevisiae will be ......EX. 2 The bundle sheath (BS) cells of maize......BS cells near veins exhibit........
All foreign words and species names should be in italics or underlined as above or in vitro, et al. -Note that the word al. is always followed by a period.
The first time you use a term that is not common knowledge, it should be defined. The cultures were grown at the restrictive temperature (18 0C) for.....
Do not start sentences with a numeral. You can either restructure your sentence or write out the word for the number. Six not 6 should start a sentence.