Lab Write-ups


Elements of the Writeups

Lab writeups are due 1 week after completing (or abandoning) each experiment. Late write-ups will get a 2 point late penalty for each week or part of a week they are late. No writeups will be accepted after 1:30PM April 22nd (section 001) or April 23rd (section 002).

Each of the 7 laboratory writeups are worth 20 points, for a total of 140 points.

Each lab writeup should be composed of two elements

  1. your lab notes
  2. an Isolate Description

The only exception to this is the Plate Count Anomaly, for which no Isolate Description is required.


Lab Notes

The format for laboratory writeups is the same as used in a research laboratory. Your notes should be maintained continuously and in lab. Do not recopy or type your notes. You need to keep your notes for each experiment separate, so you can turn each one in separately when it's finished. Probably the best method is to keep looseleaf pages in a binder, so that pages can be added as needed.

Each day in lab you should make a dated entry for each of your ongoing experiments. If you didn't do anything, make a note to that effect. Then for each experiment, write down what you did (not what you were supposed to do, but what you actually did!) and what you saw. Write down any procedures, observations, calculations, dilutions, media, etc, that are relevant. Include all controls. Everything you do and everything you see needs to be written down. As you go, make diagrams, graphs, drawings or tables to enhance or organize the data. Document by photograph or detailed drawing any data you can.

Details are the key - be sure you describe colonies, cells, innocula, etc, so that a reader can clearly visualize what you saw or did. For example, saying you "put a pinch of dirt in the tube" isn't good enough. About how much dirt? What did it look like? Where did it come from? When was it collected? Likewise, describe colonies and cells seen under the microscope in detail; e.g. "rods" isn't enough to describe an organism. Was it motile? If so, what did it's motion look like? Are the cells large or small? What is the ratio of length to width? What is the consistency of the cytoplasm (e.g. granular or smooth)? Are the ends rounded or square? Are the cells all individual, or are some in pairs or chains? What fraction of each?

Before you turn in each experiment, write a short summation (a paragraph) of the results of the experiment. Indicate what the results mean - for example, did you isolate what you wanted to? What did you isolate? If it didn't work, why not?


Isolate Description

At the end, write up a brief description of the organism you isolated based on information from the literature (this is not required for the Great Plate Count Anomaly experiment). Be sure to include morphology, metabolism, habitat/ecology, life cycle, and anything else of particular interest. Think of this as a one or two page biography of the organism. In some cases, you may be able to identify the organism down to the species (for example, if you get Rhodospirillum rubrum), in other cases you may know the genus (e.g. Rhodomicrobium), or group (Bacillus & relatives) or huge phylogenetic assembly (e.g. filamentous fungi); this is OK, do the best you can with the available information, then write your description about the group at whatever level you have it identified.

In cases where an isolation is not successful, and there is no time to start over, the lab notes still should be turned in, and will be graded on the same basis as the other labs - there is no penalty! Because you will not be able to give an isolate description of the organisms you didn't isolate, instead give a description of how you would go about changing your procedure to improve the odds of getting this organism.