Humboldt State University ® Department of Chemistry

Richard A. Paselk

Chem 431
Biochemistry

Laboratory Records & Write-ups

Notebooks

Each individual will keep a bound, accurate, and detailed lab book where records are kept of procedures, modifications of procedures, (both planned and unplanned), your observations (in such a way that you can understand and explain to me in exacting detail!) and any difficulties encountered, things that bothered you, etc. The lab book should be a record of your work so that you could repeat it in 10 years, or, more practically, explain it to me in three or four weeks.

A variety of lab texts (e.g. Ninfa & Ballaou, Fund. Lab. Appr. Bioch. and Biotech.; Boyer, Mod. Exp. Biochem.; etc.) give a good summary of what the notebook should contain as well as basic lab practices, techniques and experiment design. In addition preliminary conclusions should be included!

This instructor requires a permanent bound research notebook with numbered pages.

• The write-up is to be kept, in permanent form (no pencil), on the right-hand pages. Any doodling you may wish to do can be done on the left-hand pages.
• Do not write pages and pages of description. The very briefest summary of what the experiment is about including reference to the source of the experiment (Lab manual, handout, etc.) will suffice. Be concise!
• All data and the results which follow from the data should be presented in a neat and logical manner.
  • Weighing data should include mass of tare, total mass, and mass of material being weighed.
  • All volumes delivered must be given with the proper units (mL, L, µL, etc.). 
• These data should be entered into the notebook (not on filter paper, paper towels, etc.) as the experiment is being done. Transferring data from somewhere else into the notebook leads to transcription errors.

When tables, plots, or flow charts are required, include them.

• Where graphical plots are required make sure the coordinates are clearly tabulated and then draw the curve directly on graph paper, clearly labeling the axes and glue the graph paper to the page.
• Do not attempt to extend the page by gluing on extra sheets.
• A good graph should fill the page as much as possible, all plotted points should be clearly visible (draw a small circle around them), and a smooth curve should be constructed. A good plot, like a chemical equation, is worth a thousand words.
• Whenever calculations are to be made, show your calculations and include the appropriate units. A number alone, without units or calculations to support it, is meaningless and invalid.
• When many similar calculations are to be made, one sample calculation will suffice.

In chromatographic experiments include Xerox copies of the chromatograms upon which the results are based. Do not include the originals—the residual solvents in them are often toxic. Gel electrophoretograms do not always copy well, so use a good hand copy or a dried gel. When copies or other materials are placed in the notebook attach them permanently!!

Notebooks will be collected at the beginning of the last class before final exam week. (For Fall 2008 the due date is December 12.)

Examples of expected Notebook contents by Experiment:

Lactabumin

Electrophoresis

• A Log MW vs. elution volume plot must be included in your notebook.
• This plot should have proper axis and units, including log scales as appropriate.
  • These plots are best accomplished with a spreadsheet or graphing program.
    • Values should be entered directly into the spreadsheet, no calculations are necessary.
    • Copies of the spreadsheets should be included with the resultant plots.
  • Some suggestions if you are using Excel:
    • Use the scatter-plot function.
    • Choose the log best fit XXXXX
    • Extend your plots under XXXX
• After the completion of the lab you should write some brief paragraphs summarizing your results and your initial impressions of their interpretation/meaning that you can refer to later when you write your papers.

Tyrosinase

• Enzyme source, instruments etc.
• HP plots for assays.
• Cornish-Bowden (direct-linear) plots must by included in the notebook for each assay series. These plots should be drawn as the data is gathered in the lab for each assay and before the next series is prepared or run!
• These plots must be drawn on graph paper with pen or pencil and ruler – computer generated plots are not acceptable.
• After the completion of the assays the data should be replotted as Lineweaver-Burke (double-reciprocal) or Eadie-Hofstee plots. Copies of these plots must also be included in your notebooks with brief discussion of the results.
• These plots are best accomplished with a spreadsheet or graphing program.
• Reciprocal calculations can be best accomplished on the spreadsheet.
• Copies of the spreadsheets should be included with the resultant plots.
• Some suggestions if you are using Excel:
• Use the scatter-plot function
• Choose the linear best fit XXXXX
• Extend your plots under XXXX
• After the completion of the lab you should write some brief paragraphs summarizing your results and your initial impressions of their interpretation/meaning that you can refer to later when you write your papers.

 

Write-ups

1.   Individual lab groups (generally pairs) will meet with me during scheduled lab hours to discuss their work and how to prepare and interpret their data for “publication”. All notebooks must be brought. Appointments are recommended.

2.   Each individual will write up each experiment independently, based on data gathered and conference discussions (2 above). These write-ups will follow proper journal form and will include literature references, etc. The table below tells you which journal you are going to “submit” it to. Failure to follow correct formatting or excessive grammatical errors may lead to rejection (grade of 0) of your submission (report).

All members of the group will be listed as authors, but the writer will be the “first author”. Thus, from a group of two I will expect two separate and different “articles”, with the order of the authors’ names reversed in the two. These “articles” will be the only lab work turned in.

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Last modified 10 November 2008